Note: Descriptions are shown in the official language in which they were submitted.
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LIVING OLEFIN POLYMERIZATION PROCESSES
This application is a divisional application of copending application
2,285,964, filed April 9, 1998.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to living olefin polymerization
processes, and
more specifically to initiators for such processes that are stable under
reaction conditions in the
absence of olefin monomer such that polymers of low polydispersity can be
synthesized.
2. Discussion of the Related Art
Polymers are used in a large number of applications, and a great deal of
attention has
been paid to developing synthetic routes that result in polymers having
optimal physical and
chemical properties for a given application.
Block copolymers are one class of polymers that have broad utility. For
example, block
copolymers have been employed as melt processable rubbers, impact resistant
thermoplastics and
emulsifiers. As a result, these materials have been the focus of a
particularly large amount of
research and development both in industry and academia, and a variety of
approaches to block
copolymer synthesis have been developed.
When preparing a block copolymer, it is generally desirable to use a synthetic
technique
that allows for control over the chain length of each polymer block and the
polydispersity of the
resulting block copolymer. For some time, attempts to provide such a method
have focused on
block copolymer formation by living polymer synthesis. In living polymer
synthesis, a metal-
containing initiator having either a metal-carbon bond or a metal-hydrogen
bond is reacted with
an olefin monomer to form a polymer chain via the successive insertion of the
first olefin
monomer into a metal-carbon bond between the metal of the initiator and the
growing polymer
chain. If the initiator is a metal-hydride complex, the first metal-carbon
bond is formed when the
olefin inserts into the metal-hydride bond. When the olefin monomer is
depleted, a second olefin
monomer is added, and a second polymer block is formed by successively
inserting, into the
metal-carbon end group, the second monomer, ultimately resulting in a block
copolymer
including a first polymer block connected to a second polymer block. Since
each polymer block
is formed sequentially, the initiator and propagating species should be stable
under reaction
conditions in the absence of olefin monomer.
To provide a block copolymer having sizable polymer blocks of low
polydispersity, the
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rate of chain propagation (i.e., olefin monomer insertion into the metal-
carbon bond) should be
substantially greater than the rate of chain termination or transfer. To
prepare a block copolymer
having the lowest possible polydispersity, the rate of initiation should be at
least as great as the
rate of propagation.
Polymerization termination is typically dominated by R-hydride elimination
with the
products being a polymer chain having a terminal carbon-carbon double bond and
the initiator
having a metal-hydrogen bond. Termination of polymerization also can occur if
the initiator
decomposes in some other manner, such as transfer of the polymer chain from
the initiator to
some other element that is relatively inactive in or for olefin
polymerization. Hence, the
achievable chain length of copolymer blocks and the polydispersity of the
block copolymer are
principally determined by the relative rates of olefin insertion and R-hydride
elimination, as well
as initiator stability toward other modes of decomposition, especially in the
absence of olefin
monomer.
Attempts at synthesizing polymers using living polymer synthesis have employed
a
variety of initiators. For example, as reported in JACS 118, 10008 (1996),
McConville and co-
workers have used a diamido-titanium initiator to form polymers by
polymerizing a-olefins. In
addition, Turner and co-workers have developed a hafnium-containing
cyclopentadienyl initiator
for preparing block copolymers from a-olefin monomers (published PCT patent
application WO
91/12285). Furthermore, Horton and co-workers report diamido-group IVB metal
initiator
effective in providing homopolymer synthesis (Organometallics 15, 2672
(1996)).
Despite the commercial motivation for developing a living polymer synthetic
method for
block copolymer preparation, known methods of block copolymer synthesis can
suffer from a
variety of problems. For example, the initiators used can be unstable under
reaction conditions
in the absence of olefin monomer, resulting in an inability to form additional
homopolymer
blocks to form a block copolymer. Moreover, the efficiency of block copolymer
formation can
be reduced due to the formation of significant amounts of homopolymer. In
addition, due to the
low temperatures used, the products formed using many known initiators have
relatively low
molecular weights and are more appropriately classified as oligomers.
As seen from the foregoing discussion, it remains a challenge in the art to
provide a
method of synthesizing block copolymers that includes the use of a initiator
that is stable in the
absence of olefin monomer such that the resulting block copolymers have low
polydispersities.
Such an initiator would also offer the advantage of resulting in relatively
small amounts of
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homopolymer synthesis.
SUMMARY OF THE INVENTION
In one illustrative embodiment, the present invention provides a composition
of matter
having a structure:
[R,-X-A-Z- R2] 2-
X and Z are each group 15 atoms. R, and R2 are each a hydrogen atom or group
14 atom-
containing species. A is either
L,-Y,-L2
or
L1-Y2-L2
1
R3
Y, is a group 16 atom, and Y2 is a group 15 atom. R3 is H or a group 14 atom-
containing species.
L, and L2 are each dative interconnections including at least one group 14
atom bonded to Y, or
Y2.
In another illustrative embodiment, the present invention provides a method of
synthesizing a block copolymer. The method comprises performing a first
reaction and a second
reaction. In the first reaction, a first monomeric species containing a
terminal carbon-carbon
double bond is exposed to an initiator containing a metal, and the terminal
carbon-carbon double
bonds of the first monomeric species are allowed to insert successively into
the initiator to form a
carbon-metal bond thereby forming a first homopolymeric block of the first
monomeric species
connected to the metal of the initiator. In the second reaction, a second
monomeric species
containing a terminal carbon-carbon double bond is exposed to the initiator,
and terminal
carbon-carbon double bonds of the second monomeric species are allowed to
insert successively
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into the initiator, first inserting into the bond between the block of the
first homopolymeric block
and the metal of the initiator, thereby forming a copolymer including the
first homopolymeric
block connected to a homopolymeric block of the second monomeric species, the
copolymer
having a polydispersity of no more than about 1.4.
In yet another illustrative embodiment, the present invention provides a
method of
synthesizing a block copolymer. The method comprises: exposing a first
monomeric species
having a terminal carbon-carbon double bond to an initiator including a metal
and allowing
terminal carbon-carbon double bonds of the first species to insert
successively into the initiator to
form a metal-carbon bond thereby forming a first homopolymeric block of the
first monomeric
species having a bond to the metal of the initiator; and exposing a second
monomeric species
containing a terminal carbon-carbon double bond to the initiator and allowing
terminal
carbon-carbon double bonds of the second species to insert successively into
the initiator, first
inserting into the bond between the first homopolymeric block and the metal,
thereby forming a
copolymer including the first homopolymeric block connected to a second
homopolymeric block
of the second monomeric species, the method producing no more than about 25%
by weight of
the first homopolymer or the second homopolymer relative to a total amount of
polymer product.
In a further illustrative embodiment, the present invention provides a block
copolymer
which comprises a first homopolymer block and a second homopolymer block
connected to the
first homopolymer block. The first homopolymer block comprises a
polymerization product of
at least about ten units of a first monomeric species having a formula
HzC=CHR,. The second
homopolymer block comprises a polymerization product of at least about ten
units of a second,
different monomeric species having a formula H2C=CHR2. R, and R2 can be the
same or
different, and each are H or a linear, branched, or cyclic hydrocarbon that is
free of non-carbon
heteroatoms. The block copolymer has a polydispersity of at most about 1.4.
In still a further illustrative embodiment, the present invention provides a
method of
polymerization. The method comprises: reacting an initiator having a metal
atom with a
monomeric species having a terminal carbon-carbon double bond to allow
terminal
carbon-carbon double bonds of monomers to insert successively into the
initiator to form a
metal-capped polymer of the monomeric species connected to the metal through a
metal-carbon
bond. The metal-capped polymer is stable, in a solvent essentially free of the
monomeric species
and electron donors such as water and free oxygen at a temperature of at least
about -50 C. The
metal-capped polymer is capable of then reacting further with monomeric
species and inserting
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the monomeric species successively into a metal carbon bond.
The invention also provides a block copolymer,
comprising: a first homopolymeric block comprising a
polymerization product of at least about ten units of a
5 first monomeric species having a formula H2C=CHR1; and a
second homopolymeric block comprising a polymerization
product of at least about ten units of a second, different
monomeric species having a formula H2C=CHR2, the second
homopolymeric block being connected to the first
homopolymeric block, wherein R1 and R2 can be the same or
different and each are H or a linear, branched, or cyclic
hydrocarbon that is free of non-carbon heteroatoms, and
wherein the block copolymer has a polydispersity of at most
about 1.4.
In one aspect, this divisional application
provides a method of synthesizing a block copolymer, the
method comprising: performing a first reaction comprising
exposing a first monomeric species containing a terminal
carbon-carbon double bond to an initiator containing a metal
and allowing terminal carbon-carbon double bonds of the
first monomeric species to insert successively into the
initiator to form a metal-carbon bond thereby forming a
first homopolymeric block of the first monomeric species
connected by a bond to the metal of the initiator; and
performing a second reaction comprising exposing a second
monomeric species containing a terminal carbon-carbon double
bond to the initiator and allowing terminal carbon-carbon
double bonds of the second monomeric species to insert
successively into the initiator, first inserting into the
bond between the block of the first homopolymeric block and
the metal of the initiator, thereby forming a copolymer
comprising the first homopolymeric block bonded to a second
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homopolymeric block of the second monomeric species, the
copolymer having a polydispersity of no more than about 1.4.
In a further aspect, this divisional application
provides a method of synthesizing a block copolymer, the
method comprising: exposing a first monomeric species having
a terminal carbon-carbon double bond to an initiator
comprising a metal and allowing terminal carbon-carbon
double bonds of the first species to insert successively
into the initiator to form a metal-carbon bond thereby
forming a first homopolymeric block of the first monomeric
species having a bond to the metal of the initiator; and
exposing a second monomeric species containing a terminal
carbon-carbon double bond to the initiator and allowing
terminal carbon-carbon double bonds of the second species to
insert successively into the initiator, first inserting into
the bond between the first homopolymeric block and the
metal, thereby forming a copolymer including the first
homopolymeric block connected to a second homopolymeric
block of the second monomeric species, the method producing
no more than about 25% by weight of the first homopolymer or
the second homopolymer relative to a total amount of polymer
product.
In a still further aspect, this divisional
application provides a method of polymerization, the method
comprising: reacting an initiator having a metal atom with a
monomeric species having a terminal carbon-carbon double
bond to allow terminal carbon-carbon double bonds of
monomers to insert successively into the initiator to form a
metal-capped polymer of the monomeric species connected to
the metal through a metal-carbon bond, the metal-capped
polymer being stable, in a solvent substantially free of the
monomeric-species and electron donors at a temperature of at
least -50 C and for then reacting further with
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monomeric species and inserting the monomeric species
successively into a metal carbon bond.
In a yet further aspect, this divisional
application provides a block copolymer, comprising: a first
homopolymeric block comprising a polymerization product of
at least about ten units of a first monomeric species having
a formula H2C=CHR1; and a second homopolymeric block
comprising a polymerization product of at least about ten
units of a second, different monomeric species having a
formula H2C=CHR2, the second homopolymeric block being
connected to the first homopolymeric block, wherein R1 and R2
can be the same or different and each are H or a linear,
branched, or cyclic hydrocarbon that is free of non-carbon
heteroatoms, and wherein the block copolymer has a
polydispersity of at most about 1.4.
DETAILED DESCRIPTION
In one aspect, the present invention relates to a
ligand (referred to herein as [LIG]) having the following
representative structures:
2
[RI-X-L1-Y1-L2-Z-8212 X-LI-Y1-L2-Z
2-
1R1-X-L1-Y2-L2-Z-R212 X-L1-Y2-L2-Z
I I
R3 R3
X and Z are group 15 atoms such as nitrogen and
phosphorous that are each selected to form an anionic or
covalent bond with a metal atom, particularly a transition
metal, while simultaneously including two substituents
(e.g. , L1 and R1 or L2 and R2) . Y1 is a group 16 atom such as
oxygen or sulfur that is selected to form a dative bond with
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Sc
another atom such as a metal atom, particularly a transition
metal, while simultaneously including two substituents
(e . g . , L1 and L2) . Y2 is a group 15 atom such as nitrogen or
phosphorus that is selected to form a dative bond with
another atom such as a metal atom, particularly a transition
metal, while simultaneously including three substituents
(e.g., L1, L2 and R3) . - represents a dative
interconnection between X and Z, such as one or more group
14 atoms. In certain embodiments, Y1 is preferably oxygen
and X and Z are the same atom, more preferably, X and Z are
each nitrogen atoms.
A "dative bond" herein refers to a bond between a
neutral atom of a ligand and a metal atom in which the
neutral atom of the ligand donates an electron pair to the
metal atom. As used herein, an "anionic bond" denotes a
bond between a negatively charged atom of a ligand and a
metal atom in which the negatively charged atom of the
ligand donates an electron pair to the metal atom.
L1 and L2 each represent a dative interconnection
between X, Y1r Y2 and/or Z, L1 and L2 each correspond to at
least one atom, preferably 1-4 atoms, and most preferably 2
atoms. The atoms that make up the interconnection most
commonly are group 14 atoms, such as carbon or
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silicon. Preferably, L, and L2 each represent a C, unit such as -(CH2)2-, -
(CF2)2-, -(o-C6H4)-, -
CH2Si(CH3)2- and the like. In certain embodiments, L, and L2 may be selected
such that X, Y1,
Y2 and/or Z are not rigidly interconnected (i.e., there is at least one
rotational degree of freedom
between these atoms).
Although- depicted in an arrangement in which X is interconnected to Y, or Y2
and Y, or
Y2 is interconnected to Z, other arrangements of X, Y, or Y2 and Z are
envisioned to be within
the scope of the present invention. For example, in certain embodiments, X may
be
interconnected to Z through L, or L2. The arrangement of X, Y, or Y2 and Z is
limited only in
that, simultaneously, X and Z should each be selected to form anionic or
covalent bonds with a
metal atom such as a transition metal while Y, or Y2 should each be selected
to form a dative
bond with a metal atom such as a transition metal. Upon reading this
disclosure, those of
ordinary skill in the art will recognize a combination of atoms X, Y1, Y, and
Z, and
interconnections L, and L2 that will provide this capability.
R,-R3 can be the same or different and preferably are H or group 14 species
such as
linear, branched, cyclic and/or aromatic hydrocarbons free of non-group 14
heteroatoms that
could bind to an activated metal center. One set of exemplary R,-R3 units
include saturated or
unsaturated straight, branched or cyclic hydrocarbons. Another example of R, -
R3 units is
trimethylsilyl groups. Still a further example of R,-R3 units is 2,6-
disubstituted phenyl rings
such as 2,6-dimethylphenyl.
In another aspect, the invention relates to metal-containing catalyst
precursors, preferably
group 4 metal-containing catalyst precursors, for use in the living
polymerization of olefin
monomers having terminal carbon-carbon double bonds. These catalyst precursors
are
particularly stable under reaction conditions in the absence of such olefin
monomer. That is,
when the reaction mixture is substantially depleted of the olefin monomer, the
catalyst precursor
remains stable in the absence of water, oxygen, basic donor ligands and the
like. As a result of
the catalyst precursor's stability, the resulting polymers (e.g.,
homopolymers, random
copolymers and/or block copolymers) have low polydispersities. Furthermore,
when used to
prepare block copolymers, the amount of homopolymer produced is relatively
low.
Substantial depletion of an olefin monomer relates to a situation in which the
olefin
monomer is present in an amount below the detection limit of standard NMR
spectrometers such
that the olefin monomer cannot be detected using such standard NMR
spectrometers. Typically,
an olefin monomer is substantially depleted when less than about 5% of the
olefin monomer
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remains as olefin monomer in solution relative to the amount of olefin monomer
initially present
in the solution.
The catalyst precursors of the present invention have the following
representative
molecular structures:
[R1 -X-L1 - Y1-L2-Z-R2]MRaRs [X-LI -Y, -L2-Z]MR4R5
Y L Z-R ]MR R [X-LI-Y2-LZ-Z]MRQR5
[R _X-L, 2 2 2 4 5
I
I R3
3
R3
That is,:
L Y1` ~ Z
- iL1~ i 1~ L2
\ Z R2 X M
R1-X I
M 1_.
R4 R5 R4 R5
R R3
3 1
---* Y2~, (L1 R1-X I: Z-R2 ` Z
`
M / M
R4 R5 R4 R5
M is a metal atom that can form a metal-carbon bond into which an olefin can
be inserted.
Those of ordinary skill in the art will recognize metals that meet this
requirement. For example,
M may be selected from metals of groups 3-6, late transition metals such as
those of group 10,
actinides and lanthanides. In one set of preferred embodiments, M is selected
from Ti, Zr or Hf.
X and Z each form an anionic or covalent bond to M while YI or Y2 each form
dative bonds to
M. Preferably, the length of the M-Y1 and M-Y2 bonds is at most about 2.5
Angstroms, more
preferably at most about 2.3 Angstroms, most preferably at most about 2.1
Angstroms,
depending upon the size of M.
R4 and R5 should be good leaving groups such that living polymerization can
occur via
the removal of R4 or R5 and the formation of an initiator, as described below.
Typically, R4 and
R5 are substantially similar to R1-R3. Preferably, R4 and R5 are linear or
branched alkyls having
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a length of from 1-10 carbon atoms. In some embodiments R4 and/or R5 can be
hydrogen.
The present invention is not limited by the particular geometrical
configuration of the
catalyst precursor. However, in certain embodiments, the catalyst precursor
may have a
nonpianar geometry, such as, for example, trigonal bipyramidal. In some
embodiments, it is
preferable that the catalyst precursor have a geometrical configuration such
that X, Y, or Y2 and
Z are interconnected in the same plane.
In a particularly preferred set of embodiments, a catalyst precursor is
provided having one
of the structures:
0Q
CH3 N,, M ,N CH3
X- / CH3 C3R4 R5C3 .CH3
[NON]M(R4)(RS)
li O li
M ~N, Si(CH
(CH3)3Si
3)3
/ IN
R4 R5
[TMSNON]M(R4)(RS)
i-Pr 0,-,) i-Pr
M/N li
i-Pr R4 R5 i-Pr
[(2,6-i-Pr2-C6H3NCH2CH2)20]M(R4)(RS)
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It is to be noted that, in certain embodiments, any or all of the isopropyl
groups of [(2,6-i-
Pr2-C6H3NCH2CH2)20]M(R4)(R5) may be replaced with H or branched or straight
chain alkyl
groups. As will be appreciated by one skilled in the art, such alkyl groups
should be selected
such that an olefin monomer's access to M during polymerization (described
below) is not
sterically hindered by these alkyl groups. Typically, such alkyl groups have
at most about 20
carbon atoms and include, for example, methyl, propyl, t-butyl and the like.
The catalyst precursors can be prepared using standard alkylation techniques.
For
example, the protanated ligand (H2[LIG]) can be reacted with M(NMe2)4 to form
[LIG]M(NMe2)2
which is then reacted with TMSCI to form [LIG]MC12. The [LIG]MC12 is reacted
with R-MgX
to provide [LIG]MR2. The appropriate reaction conditions of from about -78 C
to about 0 C in
a solvent such as ether, diethyl ether, hydrocarbons, free of oxygen and
water, can be selected by
those of skill in the art. Alternatively, [LIG]MCI, can be reacted with
aluminoxane which first
reacts to form the dimethyl compound [LIG]M(Me)2 in situ, and then removes one
Me group to
make the active cation, serving as its counterion. This reaction is known, as
described in, for
example, published PCT patent application WO 92/12162.
During living polymerization, the catalyst precursor is activated via the
removal either R4
or R5, typically in situ, to form an initiator which is cationic in nature.
Where a stable salt can be
synthesized, this salt can be provided, stored, and used directly. Counterions
for the initiator
should be weakly-coordinating anions, for example [B(C6F5)4]-. Those of
ordinary skill in the art
can select suitable counter ions.
The initiator can be reacted with monomeric olefins having a terminal carbon-
carbon
double bond (H2C=CHR6) to provide polymers, where R6 is hydrogen or a
hydrocarbon such that
the olefin can be a straight, branched, cyclic or aromatic hydrocarbon.
Furthermore, the
hydrocarbons may include additional carbon-carbon double bonds. Preferably,
any additional
carbon-carbon double bonds are internal (non-terminal). Preferably, these
monomers are
substantially devoid of any heteroatoms. Examples of such monomers include,
but are not
limited to, a-olefins such as ethylene, 1-propylene, 1-butene, 1-hexene, 1-
heptene, I -octene, 1-
nonene, 1-decene, 4-methyl- I -pentene and the like.
Initiation of the polymerization reaction occurs by insertion of the carbon-
carbon double
bond of the species H2C=CHR6 into a metal-carbon bond of the initiator. During
reaction of the
initiator and monomeric olefin, chain growth of the polymer occurs by
successive insertion of the
monomer into a bond formed between the terminal carbon atom of the polymer
chain and the
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metal atom of the initiator. It is an advantageous feature of the present
invention that, under
reaction conditions in the absence of monomer (described above), such a metal-
carbon bond
remains stable for periods of time sufficient to allow depletion of monomer
and subsequent
addition of monomer and continued chain growth. For example, the system allows
depletion of
one monomer H2C=CHR6, and addition to the system of a additional monomer
H2C=CHR7 that
can be the same monomer (for continued homopolymer growth) or a different
monomer (for
block copolymer synthesis). Preferably, a metal-carbon bond of the initiator,
such as a bond
between the metal and a polymer chain, remains stable for greater than about a
half an hour at
room temperature under reaction conditions in the absence of olefin monomer,
water, oxygen,
basic donor ligands or the like. For most known initiators used in
polymerizing these monomers,
the metal-carbon bond formed between the initiator and the polymer chain is
not stable enough
for standard analytical techniques, such as NMR, to verify the existance of
the initiator,
indicating that the initiator-polymer chain species is not stable for more
than at most about one
second at room temperature. In contrast, the initiating and propagating
species of the present
invention have been verified by NMR.
This enhanced stability of this metal-carbon bond is desirable because blocks
of polymer
may be formed in a sequential fashion by adding olefin monomer, allowing the
olefin monomer
to react until it is depleted and subsequently adding more olefin monomer.
When forming block
copolymers, a first block of the copolymer may be formed (first homopolymeric
block). Upon
depletion of the first monomeric olefin, the carbon-metal bond remains stable
and a second olefin
monomer may be added to the reaction mixture to form a second homopolymeric
block that is
connected to the first homopolymeric block. During this reaction, the second
olefin monomer
first inserts into the metal-carbon bond formed between the first
homopolymeric block and the
initiator. Subsequently, the second olefin monomer successively inserts into
the metal-carbon
bond formed between the initiator and the polymer chain of the second olefin
monomer.
As a result of the initiator's stability, polymers are formed with relatively
low
polydispersities. The "polydispersity" of a polymer as used herein refers to
the ratio of the
weight average molecular weight (Mw) to the number average molecular weight
(Mn) of the
polymer according to equation 1.
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NM2
POLYDISPERSITY = (1)
NMi
where Ni is the number of mer units having molecular weight M;.
In particular, the present invention can provide block copolymers having low
polydispersities. Known block copolymers have been synthesized using anionic
polymerization
processes, but a-olefin monomers cannot be used in these processes. In known
block
copolymers, typical minimal polydispersities are on the order of about 1.5.
According to the
present invention, block copolymers preferably have a polydispersity of at
most about 1.4, more
preferably from about 1 to about 1.3, more preferably from about 1 to about
1.2, more preferably
from about I to about 1.1, and most preferably from about 1 to 1.05. The
polydispersity of a
polymer can be measured directly by a variety of techniques including, for
example, gel
permeation chromatography or by standard tests such as the ASTM D-1238
procedure.
It is a further advantage of the present invention that the initiator's
stability results in
good block copolymer formation with minimal formation of polymers formed
substantially only
of individual monomeric olefin units (homopolymer). That is, relatively highly
pure block
copolymer is formed. In known systems, the amount of homopolymer formed is
typically about
30 wt% based on the total amount of polymer formed including the block
copolymer. According
to the present invention, the amount of homopolymer formed is at most about 25
wt% based on
the total amount of polymer formed including copolymer, more preferably at
most about 15 wt%,
and most preferably at most about 5 wt%. These purity levels are preferably
realized in
combination with preferred polydispersity levels discussed above. For example,
one
embodiment involves formation of block copolymer of polydispersity of less
than about 1.4 with
homopolymer formation of at most about 25 wt% based on the total amount of
polymer formed
including copolymer.
Most known block copolymer synthesis methods are conducted at temperatures of
at
most about -78 C. At these low temperatures, it is difficult to form polymers.
Instead,
oligomers having less than 50 mer units typically are formed. It is a further
advantage of the
present invention that living polymerization processes can be successfully
conducted at relatively
high temperatures. Preferably, living polymerization occurs at a temperature
of at least about -
50 C, more preferably at least about 0 C, most preferably at least about 25 C.
At these higher
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temperatures in connection with the present invention, polymer blocks having
at least about 50
mer units, preferably at least about 75 mer units, and most preferably at
least about 100 mer units
can be formed.
The initiators of the present invention can be used for polymerization of a
variety of
combinations of monomers to form homopolymers, random copolymers of any number
or ratio
of monomers, or block copolymers of any number and size of blocks, while
providing optionally
the preferred polydispersities and/or purities discussed above. For example,
two monomers A
and B (H2C=CHR6 and H2C=CHR7) in a ratio of 2:1 can first be provided in a
reaction system,
with polymerization resulting in a random copolymer with A and B being
incorporated in a ratio
of 2:1, after depletion of these monomers. Then, because of the stability of
the initiator,
additional monomers C and D can be added to the system, and further
polymerization will result
in a product having a first block of random AB and a second block of random
CD. As discussed,
blocks of relatively pure homopolymer can be provided. For example,
polymerization of A until
depletion of A, followed by addition of B and polymerization of B resulting in
a block
copolymer AB.
The following examples indicate certain embodiments of the present invention.
These
examples are illustrative only and should not be construed as limiting.
All air sensitive manipulations were conducted under a nitrogen atmosphere in
a Vacuum
Atmospheres drybox or under argon when using Schlenk techniques. Pentane was
washed with
sulfuric/nitric acid (95/5 v/v), sodium bicarbonate, and then water, stored
over calcium chloride,
and then distilled from sodium benzophenone ketyl under N2. Reagent grade
diethyl ether, 1,2-
dimethoxyethane, 1,4-dioxane, and tetrahydrofuran were distilled from sodium.
Deuterated
solvents were passed through activated alumina and vacuum transferred to
solvent storage flasks
until use. Proton and carbon spectra were referenced using the partially
deuterated solvent as an
internal reference. Fluorine spectra were referenced externally. Chemical
shifts are reported in
ppm and coupling constants are in hertz. All spectra were acquired at about 22
C unless
otherwise noted. IR spectra were recorded on a Perkin-Elmer FT-IR 16
spectrometer as Nujol
mulls between KBr plates in an airtight cell. Microanalyses (C, H, N) were
performed on a
Perkin-Elmer PE2400 microanalyzer in our laboratory. Since the elemental
analyzer measures
moles of water, the %H was calculated assuming all D present was H, but the
actual molecular
mass was employed. GPC analyses were carried out on a system equipped with two
Alltech
columns (Jordi-Gell DVB mixed bed - 250 mm x 10 mm (i.d.)). The solvent was
supplied at a
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flow rate of 1.0 mL/min. with a Knauer HPLC pump 64. HPLC grade CH2C12 was
continuously
dried and distilled from CaH2. A Wyatt Technology mini'Dawn light scattering
detector coupled
to a Knauer differential-refractometer was employed. The differential
refractive index
increment, dn/dc, was determined assuming that all polymer that was weighed
for the run
(usually about 5 mg to ::L 0.1 mg) eluted from the column. For poly(1-hexene)
polymers, to
minimize polymer weighing error the average value for dnldc (0.049 mL/g) from
18 runs (0.045
to 0.053 mL/g) was employed and the molecular weights recalculated. The yields
for poly(1-
hexene) were essentially quantitative (about 97% to about 100%).
Example 1
[NON]Ti(NMe2)2 was synthesized as follows. LiBu (1.6 M in hexane, 4.2 mL) was
added to a solution of H2[NON] (1.09 g, 3.36 mmol) in diethyl ether (30 mL) at
-35 C. The
mixture was warmed to room temperature and stirred for 4 h. A suspension of
TiCI2(NMe2)2
(696 mg, 3.36 mmol) in diethyl ether (20 mL) was added to the solution
containing the
Li2[NON] at -35 C. The mixture was warmed to room temperature and stirred for
15 h. After
TM
filtration through Celite all volatiles were removed in vacuo. The residue was
dissolved in a
minimum of methylene chloride and layered with pentane. Cooling to -35 C
afforded orange
crystalline solid; yield 864 mg (56%): 1H NMR (C6D6) S 6.92 (m, 6H), 6.63 (m,
2H), 3.13 (s,
12H, NMe2), 1.28 (s, 6H, CMe(CD3)2); 13C NMR S (C6D6) 150.93, 147.12, 124.37,
123.28,
120.29, 118.60, 60.20, 47.84, 32.43, 31.93 (m).
Example 2
[NON]TiCl2 was synthesized as follows. A Schlenk tube was charged with
[NON]Ti(NMe2)2 (379 mg, 0.83 mmol), TMSCI (270 mg, 2.49 mmol) and toluene (10
mL).
The solution was heated to 110 C for 7 days, during which time the color of
the solution turned
black-purple. The volatile components were removed in vacuo and the residue
recrystallized
from methylene chloride/pentane at -35 C; yield 286 mg (78%): 1 H NMR (C6D6)
6 6.84 (m,
4H), 6.57 (m, 4H), 1.33 (s, 6H, CMe(CD3)2); 13C NMR (C6D6) S 147.78, 142.14,
126.71,
124.41, 120.58, 118.86, 64.77, 30.57, 30.35 (m). Anal. Calcd for
C20H14D12C12N2OTi: C,
54.43; H, 5.89; N, 6.35. Found: C, 54.57; H, 5.96; N, 6.13.
Example 3
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[NON]TiMe2 was synthesized as follows. A solution of McMgCI in THE (3.0 M, 350
uL) was added to a solution of [NON]TiCl2 (230 mg, 0.52 mmol) in ether (10 mL)
at -35 C.
The color immediately changed from dark purple to orange and white solid
precipitated. The
mixture was warmed to room temperature and stirred for 15 min. All volatiles
were removed in
vacuo and the residue extracted with pentane (about 10 mL) over a period of
about 5 min. The
mixture was filtered through Celite and the pentane removed in vacuo to afford
an orange red
solid which was recrystallized from a mixture of ether and pentane at -35 C;
yield 162 mg
(78%): 1H NMR_6_6.87 (m, 6H), 6.56 (m, 2H), 1.60 (s, 6H, TiMe2) 1.42 (s, 6H,
CMe(CD3)2);
13C NMR (C6D6) 6 148.49, 143.47, 126.1, 122.05, 121.42, 119.31, 64.58, 60.15,
31.37, 30.85
(m). Anal. Calcd for C22H20D12N2OTi: C, 65.98; H, 8.05; N, 6.99. Found: C,
66.07; H, 7.94;
N, 6.84.
Example 4
[NON]Zr(NMe2)2 was synthesized as follows. H2[NON] (6.48 g, 20 mmol) and
Zr(NMe2)4 (5.34 g, 20 mmol) were dissolved in pentane (40 mL). Upon standing
at room
temperature colorless crystals precipitated. After 2 days the solid was
filtered off (6.9 g). The
supernatant was concentrated and cooled to -35 C overnight yielding a second
crop of colorless
solid (1.15 g); total yield 8.05 g (80%): 1H NMR (C6D6) S 6.97 (m, 6H), 6.55
(m, 2H), 2.94 (s,
12H, NMe2), 1.33 (s, 6H, CMe(CD3)2); 13C NMR (C6D6) 6 147.79, 145.67, 125.62,
122.39,
118.25, 117.84, 57.04, 43.60, 32.06, 31.99 (m). Anal. Calcd for
C24H26D12N4OZr: C, 57.43; H,
7.57;N,11.16. Found: C, 57.56; H, 7.76; N, 11.16.
Example 5
[NON]Zr12 was synthesized as follows. A Schlenk tube was charged with
[NON]Zr(NMe2)2 (3.5 g, 7.0 mmol), methyl iodide (15 g, 106 mmol), and toluene
(100 mL).
The pale yellow solution was heated to 50 C for two days, during which time
white Me4NI
precipitated from the reaction and the color of the solution turned bright
orange. The Me4NI was
filtered off, the solvents were removed from the filtrate in vacuo, and the
residue was washed
with pentane (10 mL) to afford a yellow solid. The crude product can be
recrystallized from
toluene layered with pentane, but was used in subsequent reactions without
further purification;
yield 4.14 g (89%): 1H NMR (C6D6) S 6.79 (m, 6H), 6.56 (m, 2H), 1.36 (br s,
6H, CMe(CD3)2);
13C NMR (C6D6, 701C) 6 146.83, 139.43, 127.90, 123.95, 123.29, 119.42, 60.21,
31.26, 30.71
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(m). Anal. Calcd for C20H14D12I2N2OZr: C, 35.98; H, 3.93; N, 4.20. Found: C,
35.71; H,
3.94; N, 3.88.
Example 6
[NON]ZrMe2 was synthesized as follows. A solution of McMgI in diethyl ether
(2.8 M,
2.3 mL) was added to a suspension of [NON]ZrI2 (2.119 mg, 3.17 mmol) in
diethyl ether (50
mL) at -35 C. The reaction mixture was allowed to warm to room temperature
and was stirred
until the yellow solid was replaced by white precipitate (30 min). All
volatile solvents were then
removed in vacuo and the off-white residue was extracted with pentane (50 mL).
The extract
was filtered and the pentane was removed in vacuo. The crude product was
recrystallized from a
mixture of pentane and ether to afford pale yellow crystals; yield 1.02 g
(72%): 1H NMR (C6D6)
S 6.90 (m, 6H), 6.53 (m, 2H), 1.36 (s, 6H, CMe(CD3)2), 0.84 (s, 6H, ZrMe2);
13C NMR (C6D6)
6 148.08, 142.87, 126.50, 122.46, 120.13, 119.28, 57.00, 45.60, 31.13, 30.59
(m). Anal. Calcd
for C22H2OD 12N2OZr: C, 59.54; H, 7.21; N, 6.31. Found: C, 59.81; H, 7.19; N,
6.39.
Example 7
{[NON]ZrMe}[MeB(C6F5)3] was synthesized as follows. A solution of B(C6F5)3 (35
mg, 67 ,umol) in pentane (5 mL) that had been cooled to -35 C was added to a
solution of
[NON]ZrMe2 (30 mg, 67 E.cmol) in pentane (5mL). The mixture immediately turned
bright
yellow. A solid precipitated when the B(C6F5)3 solution was added at -35'C,
but it dissolved
when the mixture was warmed to room temperature. The slightly cloudy bright
yellow solution
was stirred at room temperature for 5 min, filtered, and cooled to -35 C for
two days. Yellow
crystals were filtered off and briefly dried in vacuo; yield 31 mg (47%): 1 H
NMR (C6D5Br) 8
7.03-6.55 (m, 8H), 2.24 (br s, 3H, BMe), 0.98 (s, 6H, CMe(CD3)2), 0.77 (s, 3H,
ZrMe); 13C
NMR (toluene-d8, -30 uC) 8 150.24, 147.16, 141.5 (m, C6F5), 139.5 (m, C6F5),
137.77, 135.8
(m, C6F5), 123.54, 59.20, 50.90 (s, ZrMe), 29.5 (br m, tBu, B-Me); 19F NMR
(C6D6) 8 -133.14
(d, 6F, FO), -159.35 (br s, 3F, Fp), -164.27 (t, 6F, Fm).
Example 8
{[NON]ZrMe(PhNMe2)]}[B(C6F5)4] was synthesized as follows. Solid [NON]ZrMe2
(-P8 mg, 18 /2mol) was added to a suspension of [PhNMe2H][B(C6F5)4] (15 mg, 18
,umol) in
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C6D5Br (1 mL) at -35 C and the mixture was stirred for 30 min at room
temperature. 1 H NMR
(C6D5Br) 6 6.94-6.50 (m, 13H), 2.74 (s, 6H, PhNMe2), 1.17 (s, 6H, C(CD3)2Me),
0.95 (s, 3H,
ZrMe); 19F NMR (C6D5Br) -131.78 (F0), -162.11 (t, Fp), -165.94 (br m, Fm).
Example
Ethylene was polymerized using {[NON]ZrMe}[MeB(C6F5)3] as follows. A stock
solution of B(C6F5)3 (51 mg, 100 lzmol) in toluene (5 mL) was added to
[NON]ZrMe2 (44 mg,
100 ymol) dissolved in toluene (5 mL) at -35 C. The color changed to bright
yellow. The
reaction mixture was allowed to warm to room temperature. Aliquots were used
for
polymerization reactions. A solution of {[NON]ZrMe}[MeB(C6F5)3] in toluene (2
mL, 20
,umol) was added to toluene (50 mL) and the solution was stirred vigorously
under 1 atm of
ethylene. White polyethylene began to precipitate. After 120 sec the reaction
was stopped by
addition of methanol (5 mL). All solvents were removed in vacuo and the
polyethylene was
washed with methanol and dried; yield 69 mg.
Example 10
Ethylene was polymerized using { [NON]ZrMe(PhNMe2)] } [B(C6F5)4] as follows. A
stock solution of [NON]ZrMe2 (44 mg, 100 ,umol) in chlorobenzene (5 mL) was
added to
[PhNMe2H][B(C6F5)4] (80 mg, 100 imol) dissolved in chlorobenzene (5 mL) at -35
C. The
solution was allowed to warm to room temperature. Aliquots were employed for
polymerization
reactions. A solution of {[NON]ZrMe(PhNMe2)]}[B(C6F5)4] in chlorobenzene (2
mL, 20 ,umol)
was added to chlorobenzene (50 mL) and the mixture was stirred vigorously
under 1 atm of
ethylene. The reaction mixture became increasingly viscous as white
polyethylene formed and
precipitated. After two minutes the reaction was stopped by addition of
methanol (3 mL). The
volume of the mixture was reduced in vacuo and the polyethylene was
precipitated by adding a
large excess of methanol. The polymer was filtered off and dried in vacuo;
yield 540 mg.
Example 11
I -Hexene was polymerized using { [NON]ZrMe(PhNMe2)] } [B(C6F5)4] as follows.
In a
typical experiment varying amounts of hexene (0.3-3.0 mL) were added to a
solution of
{[NON]ZrMe(PhNMe2)]}[B(C6F5)4] (about 50 jcmol of [PhNMe2H][B(C6F5)4] andabout
1.1
equiv of [NON]ZrMe2) in chlorobenzene at 0 C). The carefully weighed, limiting
reagent was
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the "activator," [PhNMe2H][B(C6F5)4]. It is assumed that the amount of
catalyst precursor
formed is equal to the amount of activator when it is added to a 10% excess of
[NON]ZrMe2 in
chlorobenzene. ([NON]ZrMe2 itself is inactive.) The total volume of the
reaction mixture was
always 13.0 mL The reaction mixture was stirred for 1.5 hour and quenched by
addition of HCl
in diethyl ether (4 mL, 1.0 M). Most solvent was removed at 15 Torr (water
aspirator) at 45 C).
The viscous oil was dried at 100 mTorr at 50-60 C for 20 hours. Yields and
molecular weight
data are shown in Table 1. The molecular weights and polydispersities were
measured by light
scattering. The average value for dn/dc (0.049 mL/g) obtained (assuming total
elution) from 18
runs (0.045 to 0.053 mL/g) was employed and Mn(found) calculated using that
basis.
Table 1
Equiv 1-hexene umol cat Mn(calcd) Mn(found) MW/Mn
49 49 4144 5139 1.14
179 45 15026 15360 1.08
229 52 19210 19320 1.04
288 56 24262 24780 1.02
343 47 28901 24590 1.05
399 52 33592 35820 1.04
408 55 34349 28030 1.03
517 43 46430 39310 1.03
Example 12
H2[TMSNON] synthesis was performed as follows. A solution of BuLi in
hexanes (33 mL, 1.6 M) was added to a solution of O(o-C6H4NH2)2 (5.04 g, 25.2
mmol) in THE
(100 mL) at -35 C. The mixture was warmed up to room temperature and stirred
for 5 h.
TMSCI (7.3 mL, 58.0 mmol) was added at -35 C. The solution was warmed up to
room
temperature and stirred for 14 h. All volatile components were removed in
vacuo and the residue
extracted with pentane (60 mL) over a period of about 15 min. A white solid
was filtered off
(2.4 g) and washed with pentane (20 mL). All solvents were removed in vacuo to
give an off-
white solid; yield 8.29 g (95%): 1H NMR (C6D6) S 6.88 (m, 6H), 6.59 (m, 2H),
4.22 (br s, 2H,
NH), 0.095 (s, 18H, SiMe3).
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Example 13
[TMSNON]ZrCI2 synthesis was performed as follows. H2[TMSNON] (1.29 g,
3.75 mmol) and Zr(NMe2)4 (1.00 g, 3.75 mmol) were dissolved in pentane (10 mL)
at 25 C.
After 18 hours all volatile components were removed in vacuo. The off-white
residue was
dissolved in diethyl ether (20 mL) and TMSCI (1.4 mL, 11.25 mmol) was added.
After a few
minutes a solid began to precipitate. After 90 min the volume of the mixture
was reduced to
about 10 mL and pentane (20 mL) was added. Copious amounts of pale yellow
powder
precipitated. All solvents were removed in vacuo ; yield 1.845 g (97%): 1H NMR
(C6D6) S 6.78
(m, 4H), 6.54 (m, 4H), 0.25 (s, 18H, SiMe3).
Example 14
[TMSNON]Zr 13 Me2 was prepared as follows. A solution of 13MeMgI in diethyl
ether (1.4 mL, 0.9 M) was added to a suspension [TMSNON]ZrC12 (310 mg, 0.615
mmol) in
diethyl ether at -35 C. The solution was warmed up to room temperature and
stirred for about
15 min during which time a brown solid precipitates. 1,4-dioxane (108 mg, 1.23
mmol) was
added and all volatile components removed in vacuo. The residue was extracted
with pentane
(10 mL) for about 5 min. The solid was filtered off and washed with more
pentane (about 5 mL)
affording a brown solid and a pale yellow filtrate. The filtrate was
evaporated to dryness and the
off-white residue recrystallized from a mixture of diethyl ether and pentane
affording colorless
crystalline product; yield 155 mg (54%): 1 H NMR (C6D6) b 6.85 (m, 6H), 6.54
(m, 2H), 0.81 (d,
JCH=114 Hz, 6H, Zr13Me2), 0.26 (s, 18H, SiMe3); 13C NMR (C6D6) 8 47.16
('3CH3).
Example 15
[TMSNON]Zr 13 Me2 was used as a polymerization initiator as follows. Inside
the
glove box a 100 mL flask was charged with Ph3C[B(C6F5)4] (49 mg, 54 ,umol) and
chlorobenzene (9 mL). [TMSNON]Zr 13 Me2 (25 mg, 54 icmol) was added as a solid
under
stirring at -35 C. The flask was capped with a rubber septum and quickly
brought outside where
it was cooled to 0 C in an ice bath. After 5 min 1-hexene (1.5 mL) was
injected with a gas tight
syringe. After 30 min the mixture was quenched with HCI in diethyl ether (3
mL, I M).
Removal of all volatile components afforded viscous material; yield 860 mg
(80%). Gel
permeation chromatography demonstrated a polydispersity of about 1.37.
Example 16
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(2,6-i-Pr2-C6H3NHCH2CH2)20 was prepared as follows. Solid (TsOCH2CH2)20
(5 g, 12.0 mmol) was added to a chilled solution of 2,6-i-Pr2-C6H3NHLi (4.53
g, 24.8 mmol) in
THE (30 ml). After stirring at RT for 24 h all volatiles were removed in
vacuo. The residue was
extracted with pentane. Removal of all volatiles gave an orange oil (4.2 g,
82%) which could be
used without further purification. The oil crystallized upon standing. 1H NMR
(C6D6) S 7.18 -
7.14 (br m, 6H, Haromat), 3.60 (t, 2H, NH), 3.48 (sep, 4H, CHMe2), 3.35 (t,
4H, OCH2), 3.07 (q,
4H, CH2N), 1.06 (d, 24 H, CHMe2).
Example 17
[(2,6-i-Pr2-C6H3NCH2CH2)20]Zr(NMe2)2 was prepared as follows. A solution
of Zr(NMe2)4 (2.5 g, 9.4 mmol) in pentane (4 ml) was added to a solution of
(2,6-i-Pr2-
C6H3NHCH2CH2)20 (4.0 g, 9.4 mmol) in pentane (14 ml). Almost instantaneous
crystallization
occurred. After standing overnight the crystals were collected and the mother
liquor was cooled
to - 30 C yielding a second crop of crystals. Total yield was 3.85 g (68%). 1H
NMR (C6D6) 8
7.15 - 7.10 (br m, 6H, Haromat), 3.71 (sep, 4H, CHMe2), 3.56 (t, 4H, OCH2),
3.33 (t, 4H, CH2N),
2.56 (s, 12H, ZrNMe2), 1.31 (d, 12 H, CHMe2), 1.28 (d, 12 H, CHMe2). 13C NMR
(C6D6) 6
150.2 (Ph), 146.2 (o-Ph), 125.2 (p-Ph), 124.2 (m-Ph), 72.8 (OCH2), 57.7
(CH2N), 42.7
(ZrNMe2) 29.0 (CHMe2), 26.9 (CHMe2), 25.4 (CHCMe2).
Example 18
[(2,6-i-Pr2-C6H3NCH2CH2)20]ZrCI2 was prepared as follows. Neat TMSCI (578
mg, 5.3 mmol) was added to a solution of [(2,6-i-Pr2-C6H3NCH2CH2)20]Zr(NMe2)2
(400 mg,
0.664 mmol) in 10 ml diethyl ether at RT. After thorough mixing by vigorous
shaking the
reaction mixture was allowed to stand overnight at RT yielding colorless
crystals (285 mg) in
73% yield. If the ethereal solution of [(2,6-i-Pr2-C6H3NCH2CH2)2O]Zr(NMe2)2 is
too
concentrated, [N2O]Zr(NMe)Cl cocrystallizes with [(2,6-i-Pr2-
C6H3NCH2CH2)20]ZrC12. 1H
NMR (C6D6) 8 7.17 (br, 4H, m-Ph), 7.15 (br, 6H, p-Ph), 3.73 (sep, 4H, CHMe2),
3.66 (t, 4H,
OCH2), 3.35 (t, 4H, CH2N), 1.51 (d, 12 H, CHMe2), 1.26 (d, 12 H, CHMe2). 13C
NMR (C6D6)
6 146.4 (Ph), 145.1 (o-Ph), 127.6 (p-Ph), 125.1 (m-Ph), 73.6 (OCH2), 59.3
(CH2N), 29.0
(CHMe2), 26.9 (CHMe2), 25.4 (CHCMe2).
Example 19
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[(2,6-i-Pr2-C6H3NCH2CH2)20]Zr(CH2CHMe2)2 was prepared as follows. A
chilled solution of BrMgCH2CHMe2 (2.51 M in ether, 28611, 0.72 mmol) was added
to a
suspension of [(2,6-i-Pr2-C6H3NCH2CH2)20]Zr(NMe2)2 (205 mg, 0.35 mmol) in
diethyl ether
(10 ml) at - 30 C. A fine precipitate slowly replaced the suspension of
crystals and after stirring
for 1.5 h at RT dioxane (63 mg, 0.72 mmol) was added. After 20 min of
additional stirring all
volatiles were removed and the residue was extracted with pentane.
Recrystallization from
pentane yielded 158 mg (72%) of colorless crystals. 1H NMR (C6D6) S 7.17 -
7.12 (br, 4H,
HAr), 3.91 (sep, 4H, CHMe2), 3.66 (br, 8H, OCH2CH2N), 1.92 (m, 2H, CH2CHMe2),
1.45 (d,
12H, CHMe2), 1.23 (d, 12H, CHMe2), 0.85 (d, 12 H, CH2CHMe2), 0.70 (d, 4H,
CH2CHMe2).
13C NMR (C6D6) 6 149.2 (C;pso), 146.0 (o-Ar), 126.2 (p-Ar), 124.6 (m-Ar), 78.1
(CH2CHMe2),
74.5 (OCH2), 58.3 (CH2N), 29.7 (CH2CHMe2), 28.9 (CHMe2), 28.4 (CH2CHMe2), 27.4
(CHMe2), 24.6 (CHMe2).
Example 20
[(2,6-i-Pr2-C6H3NCH2CH2)2O]ZrMe2 was prepared as follows. A chilled
solution of BrMgMe (4.1 M in ether, 428 ul, 1.75 mmol) was added to a
suspension of [(2,6-i-
Pr2-C6H3NCH2CH2)20]ZrC12 (500 mg, 0.85 mmol) in diethyl ether (20 ml) at - 30
iC. A fine
precipitate slowly replaced the suspension of crystals and after stirring for
2 h at RT dioxane
(154 mg, 1.75 mmol) was added. After 20 min of additional stirring all
volatiles were removed
and the residue was extracted with pentane. Recrystallization from pentane
yielded 280 mg
(61%) of colorless crystals. 1 H NMR (C6D6) S 7.15 (br, 2H, p-Ar), 7.12 (br,
4H, m-Ar), 3.84
(sep, 4H, CHMe2), 3.41 (br, 8H, OCH2CH2N), 1.38 (d, 12 H, CHMe2), 1.23 (d, 12
H, CHMe2),
).30 (s, 6H, ZrMe). 13C NMR (C6D6) 6 147.1 (C;pso), 146.5 (o-Ph), 126.5 (p-
Ph), 124.7 (m-Ph),
73.6 (OCH2), 58.6 (CH2N), 43.6 (ZrMe), 28.9 (CHMe2), 27.3 (CHMe2), 24.9
(CHCMe2).
Example 21
[NON]Hf(NMe2)2 was synthesized as follows. [NON]H2 (8.964 g, 0.027 mol)
and Hf(NMe2)4 (9.800 g, 0.027 mol) were stirred in 40 mL toluene at 115 C in a
100 mL sealed
vessel for 30 hours. Solvents were then removed in vacuo and the resulting
white
microcrystalline solid was slurried in 20 mL pentane, collected on a frit,
washed with several
portions of pentane, and dried in vacuo; yield 10.141 g (62%). 1H NMR (C6D6) 6
7.06 (m, 2,
Ar), 6.97 (m, 2, Ar), 6.90 (m, 2, Ar), 6.56 (m, 2, Ar), 3.01 (s, 12, NMe2),
1.34 (s, 6, t-Bu);
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Example 22
[NON]HfCl2 was prepared as follows. [NON]Hf(NMe2)2 (961 mg, 1.631 mmol) and
TMSCI
(1.063 g, 9.789 mmol) were stirred in 30 mL toluene at 100 C for 5 hours
during which a yellow
color developed. Solvents were removed in vacuo and the resulting yellow solid
was extracted
with Et2O/toluene (30 mL/l OmL), filtered, and solvents were removed to give
the product as a
canary yellow microcrystalline solid; yield 657 mg (70%): IH NMR (C6D6) S 6.80
(m, 6, Ar),
6.53 (m, 2, Ar), 1.31 (s, 6, t-Bu).
Example 23
[NON]HfMe2 was prepared as follows. A stirred pale yellow solution of
[NON]HfC12 (152 mg, 0.266 mmol) in 7 mL Et20 at -40 C was treated with MeMgI
(0.558
mmol, 2.8 M in Et20) whereupon MgC1I precipitated immediately. The mixture was
allowed to
warm to 25 C over 1 hour after which a few drops of 1,4-dioxane were added and
the mixture
was stirred for an additional 30 minutes. Solvents were removed in vacuo and
the product was
extracted from the white residue with 10 mL pentane, filtered through Celite,
and the filtrate
concentrated and stored at -40 C overnight. Colorless prisms were separated
from the mother
liquor and dried in vacuo: yield 91 mg, (65%). 1H NMR (C6D6) S 6.94 - 6.83 (m,
6, Ar), 6.54
(m, 2, Ar), 1.36 (s, 6, t-Bu), 0.65 (s, 6, Me) C22H2ON2D12HfO: C, 49.76; H,
8.35 N, 5.27.
Example 24
[NON]Hf(CH2CH(CH3)2)2 was prepared as follows. A stirred pale yellow
solution of [NON]HfC12 (525 mg, 0.918 mmol) in 18 mL Et20 at -40 C was treated
with
(CH3)2CHCH2MgCl (1.882 mmol, 2.5 M in Et2O) whereupon MgCl2 precipitated
immediately.
The mixture was allowed to warm to 25 C over 2 hours after which a few drops
of I,4-dioxane
were added and the mixture was stirred for an additional 30 minutes. Solvents
were removed in
vacuo and the product was extracted from the white residue with pentane,
filtered through Celite,
and the filtrate concentrated and stored at -40 C. Large colorless prisms were
separated from the
mother liquor and dried in vacuo: yield 324 mg, (57%). 1H NMR (C6D6) 8 7.02-
6.85 (m, 6,
Ar), 6.56 (m, 2, Ar), 2.43 (m, 2, CH2CHC(CH3)2), 1.37 (s, 6, t-Bu), 1.16 (d,
12,
CH2CHC(CH3)2, 1.02 (d, 4, CH2CHC(CH3)2, 3pH = 6.9); 13C(H} NMR (C6D6) 8
148.29,
142.77, 126.64, 123.73, 120.18, 119.48, 92.22, 31.57, 31.35, 30.81 (m, CD3),
29.84. Anal.
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4.55.
Example 25
{ [NON]Hflvle} [B(C6F5)4]was prepared as follows. Solid [NON]HfMe2 (15 mg,
0.028 mmol) and Ph3C[B(C6F5)4] (26 mg, 0.028 mmol) were combined and then
dissolved in
0.7 mL C6D5Br at 25 C to give an orange solution. 1H NMR (C6D5Br) 8 7.68 -
6.75 (m, Ar),
2.03 (s, 3, Ph3CMe), 1.19 (s, 6, t-Bu), 0.68 (b, 3, HfMe).
Example 26
{[NON]HfMe(2,4-lutidine)}B(C6F5)4 was prepared as follows. Solid
[NON]HfMe2 (15 mg, 0.028 mmol) and Ph3C[B(C6F5)4] (26 mg, 0.028 mmol) were
combined
and then dissolved in 0.7 mL C6D5Br in an NMR tube at 25 C to give an orange
solution. Then
2,4-lutidine (3 mg, 0.028 mmol) was syringed into the NMR tube whereupon the
solution rapidly
turned yellow. 1H NMR (C6D5Br) 6 8.39 (b, 1, 2,4-lut), 7.29 - 6.66 (m, Ar),
2.21 (b, 3, Me0rth0),
2.03 (s, 3, Ph3Me), 1.96 (s, 3, Mepara), 1.14 (s, 6, t-Bu), 0.63 (s, 3, HfMe).
Example 27
{[NON]Hf(CH2CHMe2}(2,4-lutidine)}B(C6F5)4 was prepared as follows. Solid
[NON]Hf(CH2CH(CH3)2)2 (15 mg, 0.025 mmol) and Ph3C[B(C6F5)4] (23 mg, 0.025
mmol)
were dissolved in 0.7 mL C6D5Br at 25 C followed by treatment with 2,4-
lutidine (3 mg, 0.025
mmol) whereupon the orange solution turned yellow. 1H NMR (C6D5Br) 8 8.50 (b,
1, 2,4-lut),
7.18 - 6.82 (m, Ar), 5.44 (s, 1, Ph3CH), 4.68 (s, CH2C(CH3)2, 2.42 (b, 4,
CH2CH(CH3)2) and
Meo,.t1O), 2.03 (s, 3, Mepara), 1.61 (s, CH2C(CH3)2, 1.02 (b, 6, t-Bu), 0.94
(d, 2, CH2CH(CH3)2),
0.73 (d, 6, CH2CH(CH3)2).
Example 28
Polymerization of 1-hexene by {[NON]HfMe}B(C6F5)4. A solution of
[NON]HfMe2 (15 mg, 0.028 mmol) and 1-hexene (24 mg, 0.28 mmol) in 0.5 mL
C6D5Br was
combined with a solution of Ph3C[B(C6F5)4] (26 mg, 0.028 mmol) in 0.5 mL
C6D5Br at -40 .
The resulting orange solution was transferred to an NMR tube. 1 H NMR after 10
minutes
showed the presence of Ph3CMe, no 1-hexene, and several featureless broad
resonances in 0.8 -
1.70 ppm region. An additional 10 equivalents of 1-hexene (24 mg, 0.28 mmol)
were syringed
into the NMR tube. 1 H NMR showed no remaining 1-hexene.
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Example 29
Hexene was polymerized as follows. A solution of [(2,6-i-Pr2-
C6H3NCH2CH2)20]Zr(CH2CHMe2)2 (28 mg, 44 ,umol) in PhCI (4 ml) was added to a
suspension of [PhNMe2H][B(C6F5)4] (32 mg, 40 gmol) in PhCI (8 ml) at - 30 and
the reaction
mixture stirred upon warm up to room temperature for 15 min. The reaction
mixture was cooled
to 0 and hexene (1.0 ml, 8.0 mmol) was added in one shot. The reaction was
quenched with
HCI (1.0 M in ether, 4 ml) after 80 min. All volatiles were removed in vacuo
(100 mTorr) at
1200C.
Example 30
Hexene was polymerized as follows. Neat PhNMe2 (5.1 Ml, 40 ,umol) and a
solution of [(2,6-i-Pr2-C6H3NCH2CII2)2O]Zr(CH2CHMe2)2 (28 mg, 44 pmol) in PhCI
(4 ml)
were subsequently added to a solution of Ph3C[B(C6F5)4] (37 mg, 40 ,umol) in
PhCl (8 ml) at -
30 and the reaction mixture was allowed to warm up to 0 . Hexene (1.0 ml, 8.0
mmol) was
added in one shot and after 80 min the reaction was quenched with HCI (1.0 M
in ether, 4 ml).
All volatiles were removed in vacuo (100 mTorr) at 120 C.
Example 31
Hexene was polymerized as follows. A solution of [(2,6-i-Pr2-
C6H3NCH2CH2)2O]ZrMe2 (30 mg, 55 ,umol) in PhC1(3 ml) was added to a suspension
of
[PhNMe2H][B(C6F5)4] (40 mg, 50 mol) in PhC1(9 ml) at - 30 and the reaction
mixture
stirred upon warm up to room temperature for 10 min. The reaction mixture was
cooled to 0
and hexene (1.0 ml, 8.0 mmol) was added in one shot. The reaction was quenched
with HC1 (1.0
M in ether, 4 ml) after 80 min. All volatiles were removed in vacuo (100
mTorr) at 120 C.
Example 32
Hexene was polymerized as follows. A solution of [(2,6-i-Pr2-
C6H3NCH2CH2)20]ZrMe2 (24 mg, 44 umol) in PhC1(2 ml) was added to a suspension
of
[Ph3C][B(C6F5)4] (37 mg, 40 umol) in PhC1(8 ml) at - 30 . The reaction mixture
was mixed
thoroughly by shaking and allowed to react at - 30 for 5 min. Hexene (1.0 ml,
8.0 mmol) was
added in one shot and the reaction mixture was kept at - 30 until the
reaction was quenched with
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HCl (1.0 M in ether, 4 ml) after 2 h. All volatiles were removed in vacuo (100
mTorr) at 120 C.
Example 33
A block copolymer polyhexene and polynonene was prepared as follows.
{[NON]ZrMe(PhNMe2)}1B(C6F5)4] (46 micromoles in 8.0 ml of chlorobenzene) was
generated
in situ as described in example 11. 1 -hexene (600 microliters) was added at 0
C. After 15 min
an aliquot (1.0 ml) was taken and quenched. Addition of 1-nonene (700
microliters) to the
catalyst precursor/ polyhexene mixture and workup after 30 min yielded a
polymer (756 mg)
which showed a narrow, unimodal peak in the GPC (MW/Mn 1.03). The molecular
weight (Mn)
was 23,600.
Example 34
O[o-C6H4NHC(CD3)2CH3]2 (H2[NON] was synthesized as follows. O(o-
C6H4NH2)2 (18.8 g, 94 mmol) was dissolved in acetone-d6 (120 g, 1.88 mol) and
activated 4
molecular sieves (30 g) were added. After the condensation was complete (as
judged by 1H
NMR) the molecular sieves were filtered off and the unreacted ketone was
removed in vacuo.
The imine dissolved in diethylether (60 mL) was slowly added to a precooled
solution (acetone/
dry ice) of methyllithium in diethylether (270 mL, 0.88 M). The reaction
mixture was allowed to
warm up to room temperature. After 24 h the reaction mixture was quenched by
pouring it
slowly into a beaker filled with 500 mL of a mixture of ice and water. The
product was extracted
into hexane (3x 100 mL) and the combined organic layers were filtered through
a 35 cm long and
2.5 cm wide alumina column. The solvent was evaporated in vacuo to afford 16.7
g (55%) of the
product as a viscous orange oil: 1H NMR (CDC13) 8 7.00 (m, 4H), 6.68 (m, 4H),
4.19 (br s, 2H,
NH), 1.35 (s, 6H, CMe(CD3)2); 13C (CDC13) 8145.24,138.34, 123.62, 117.76,
117.30, 115.96,
50.81, 29.81, 29.28 (m, C(CD3)2Me); MS (EI) m/e 324 (M+). Anal. Calcd for C20H
6D 12N20:
C, 74.02; H, 8.70; N, 8.63. Found: C, 74.41; H, 8.94; N, 8.30.
Having thus described certain embodiments of the present invention, various
alterations,
modifications and improvements will be apparent to those of ordinary skill in
the art. Such
alterations, modifications and improvements are intended to be within the
spirit and scope of the
present invention. For example, in the aforementioned chemical species, some
or all of the
hydrogen atoms may be replaced with deuterium atoms. Accordingly, the
foregoing description
is by way of example only. The present invention is limited only as defined by
the following
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claims and the equivalents thereto.
What is claimed is:
