Note: Descriptions are shown in the official language in which they were submitted.
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CYCLIC ARYL ETHERS, THIOETHERS, AND AMINES,
AND METHOD FOR PREPARATION
The present invention relates to novel cyclic aryl compounds, particularly
ethers, thioethers, and amines, and to a method for the preparation of these
cyclic aryl
compounds.
BACKGROUND OF THE INVENTION
Interest in the development of new polyaromatic ethers, thioethers, and
amines, and routes for the synthesis of such compounds is increasing because
of the
useful chemical and physical properties they possess.
Polyaromatic ethers, thioethers and amines belong to a class of materials
known as engineering thermoplastics, which are known to have desirable
characteristics such as thermooxidative and dimensional stability, good
mechanical
properties, and resistance to high energy radiation. These materials are also
known to
be tough, creep resistant, and to exhibit good flexural, and tensile
properties.
Aromatic polymers find application in mouldings, coatings, adhesives,
membranes
and composite matrices.
Conventional cyclic polyethers are important synthetic targets owing to their
ability to selectively complex ions. Interest in these materials originates
from the size
and nature of their cavity, which dictates whether or not such materials are
capable of
binding to compounds. Although a great deal of attention has been directed
toward
the encapsulation abilities of conventional cyclic polyethers, there is a
growing
interest in the synthesis of cyclic aryl ethers (see, for example An et al.,
J. Org. Chem,
1993:58:7694; moue et al., J. Org. Chem., 1993, 58:5411; Janetka et al. J. Am.
Chem.
Soc. 1995:117:1058-10586). Cyclic aryl ethers are appealing since the rigidity
and
stability of their structures greatly reduces the compound's conformational
freedom
which may allow for chiral recognition or catalysis at high temperature or in
hostile
environments (Mullins et al., CHEMTECH August 1993:25). Mullins et al. (Polym.
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Preprints: Am. Chem. Soc. Div. Polym. Chem. 1991;32:174) reported that cyclic
aryl
ethers may be subjected to ring-opening polymerization to produce linear
polyethers
without the release of side-products.
Conventional cyclic polyether, thioether, and amine syntheses for the
formation of macrocyclic compounds require the implementation of harsh
reaction
conditions in order to obtain the desired products in low yields. For
nucleophilic
aromatic substitution reactions, the presence of a strong electron-withdrawing
group
attached to a haloarene disadvantageously requires subsequent harsh chemical
reactions to remove the electron-withdrawing group once the reaction is
complete,
which may lead to destruction of the product formed.
Known methods for preparation of aromatic polyethers include the Ullmann
ether synthesis, the Scholl reaction, nickel-catalysed homocoupling,
conventional
nucleophilic aromatic substitution, and polycondensation (for example, Cozan
et al.,
J. Macromol. Sci. Pure Appl. Chem., 1993; 30:899). These methods may employ
elevated temperatures, copper salts or oxides as catalysts, and in some cases,
electron-
withdrawing groups are bound to a reactant as required to force the reaction.
These
factors, along with the low reaction yield in some of these methods have
resulted in a
demand for a more efficient synthetic strategy.
The complexation of chloroarene to a metallic moiety in the activation of the
aromatic ring toward nucleophilic aromatic substitution is known (see Pearson
et al.,
J. Org. Chem. 1995; 60:281-284). This methodology enables preparation of a
number
of oligomeric ethers, thioethers and amines under mild reaction conditions.
Abd-El-
Aziz et al. (Organometallics 1994;13:374 and J. Chem Soc. Dalton Trans
1995:3375)
provide reports of synthetic strategies for preparing linear aryl ethers using
dichlorobenzene cyclopentadienyl iron complexes. A chain having up to 35
pendent
cyclopentadienyl iron moieties has been reported. However, these synthetic
routes are
not capable of easily forming cyclic aryl ethers, thioethers or amines.
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Crown ethers are an example of known cyclic aryl ethers. The preparation of
dibenzo crown compounds is achieved via the nucleophilic aromatic substitution
reactions of (o-dichlorobenzene)-Cr(CO)3 with diethylene glycol and bis(2-
mercaptoethyl) ether (Baldoli et al; J. Chem. Soc. Chem Commun. 1985:1181).
Disadvantages of this particular synthetic method are the implementation of
harsh
reaction conditions and the need for a phase-transfer catalyst in order to
obtain the
desired products in rather modest yields.
SUMMARY OF THE INVENTION
An object of the invention is to provide a method for the preparation of
cyclic
aryl compounds which obviates or mitigates one or more of the above-noted
deficiencies in prior art methods.
A further objective of the invention is to provide novel cyclic aryl compounds
and cyclic bimetallized aryl compounds, particularly cyclic aryl ethers,
thioethers and
amines.
According to the invention, there is provided a method for synthesis of a
cyclic aryl compound according to Formula II:
/ n ~ xl n ~ ~ (Formula II)
n4
n3
wherein
X1 and X3 are the same or different and are each:
(a) an aromatic structure having up to 6 conjugated rings which may be
heteroaryl having C, N or S atoms, and which may include C(CH3)2,
S02, S-S, or CO or C1_6 alkyl in the structure or as substituents;
(b) a linear or branched alkyl group having from 3 to 12 carbons which may
contain S;
(c) a cyclic alkyl having from 5 to 12 carbons; or
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(d) a heterocyclic alkyl having C, S, or N;
X2 is benzene;
nl is O, S or N, and when n1 is N it may be combined with X1;
n3 is O, S or N, and when n3 is N it may be combined with X3; and
ri4 is H or C1_6 alkyl;
comprising the steps of:
(a) reacting a first dinucleophile of the formula:
~-~nl X1 n~H
wherein X1 and nl are as defined above;
with a substituted benzene metallized electron-withdrawing complex of the
formula:
n4
n2 ~ n2
4
wherein:
X2 and n4 are as defined above;
X4 is cyclopentadienyl metal or tricarbonyl metal; and
n2 is halo or nitro;
to form a linear bimetallized aryl compound of the formula:
~nl Xi y \
n4 Xz ~ xz n4
~ n2 n2
Xa. Xa.
(b) reacting said linear bimetallized aryl compound with a second
dinucleophile of the
formula:
Hn3 X3 n3H
wherein X3 and n3 are as defined above,
to form a cyclic bimetallized aryl compound according to Formula I;
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_ ~nl Xt nt \
na
na ~ \ n / ~ Formula I
n3
Xa a
wherein X1, X2, X3, X4, ni, n3 and n4 are as defined above;
(c) removing X4 from the compound of Formula I to form the cyclic aryl
compound
of Formula II.
Further, according to the invention, there is provided a cyclic bimetallized
aryl
compound having the formula:
/nt X~ nt \
na xz \ / ~ na
n X3 n
Xa 3 3 Xa Formula (I)
and a cyclic aryl compound having the formula:
~nl Xt nt \
n4 ~\ /xz na
n3 X3 n3 Formula (II)
wherein X1, X2, X3, X4 and nl, n3 and na are as defined above.
Advantageously, the method according to the invention allows preparation of a
variety of cyclic aryl compounds under mild reaction conditions and in very
high
yields. Additionally, this method permits isolation of the intermediate
bimetallic
complex of Formula I after ring closure.
Additionally, it is possible to prepare both symmetric and asymmetric cyclic
aryl compounds depending on the structure of the second nucleophile used to
close
the cyclic compound.
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BRIEF DESCRIPTION OF THE DRAWINGS
These and other features of the invention will become more apparent from the
following description in which reference is made to the appended drawings
wherein:
FIGURE 1 is an ORTEP plot of a cyclic aryl ether according to Formula II-l,
and
FIGURE 2 is an ORTEP plot of a cyclic aryl ether according to Formula II-6.
DESCRIPTION OF PREFERRED EMBODIMENTS
The present invention relates to cyclic aryl compounds and cyclic aryl
bimetallized compounds which are ethers, thioesters or amines, and to a method
for
synthesis of these compounds.
The Substituted Benzene Metallized Electron-Withdrawing, Complex
The substituted benzene metallized electron-withdrawing complex comprises
a benzene ring which is disubstituted with either halo or vitro groups, and
may
additionally be substituted with a C1_6 alkyl group. The substituted benzene
ring is
complexed to a metallized electron-withdrawing group comprising a metal ion
and
an organic group having a strong electron-withdrawing function.
The benzene ring portion of the substituted benzene metallized electron-
withdrawing complex has halo or vitro substituent groups at benzene ring
positions
i,2-; 1,3-; or 1,4-. The positioning of the substituent groups used depends on
the
type of nucleophiles used in the linkages. If the nucleophiles contain large
groups,
such as aromatic groups, the substituents are in the 1,3- or 1,4- positions.
If the
nucleophiles contains smaller groups, such as aliphatic linkages, the
substituents are
in the 1,2- or 1,3- positions. The substituent groups may be halo, for example
chlorine, fluorine, bromine, or iodine, or may be vitro. Optionally, the
benzene
ring may be additionally substituted at one of the remaining carbon positions
with a
lower alkyl group (C1_6).
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In one embodiment of the present invention the benzene ring is substituted
with two chlorines and thus the substituted benzene is either 1,2-
dichlorobenzene;
1,3-dichlorobenzene; or 1,4-dichlorobenzene.
The metallized electron-withdrawing group contains a metal which is
complexed to the substituted benzene ring, and a strong electron-withdrawing
organic group, such as cyclopentyldienyl or tricarbonyl. The metal ion can be,
for
example, Fe+, Mn+, Cr+, or Ru+.
Suitable examples of the metallized electron-withdrawing groups include but
are not limited to cyclopentadienyl metal complexes, such as cyclopentadienyl
iron
(denoted in formulae as either CpFe+ or Fe+Cp), cyclopentadienyl ruthenium,
cyclopentadienyl chromium, and cyclopentadienyl magnesium, or tricabonyl metal
complexes, such as manganese tricarbonyl, and chromium tricarbonyl.
The metal ion is complexed to the substituted benzene and can be
accompanied by a counter ion such as, for example but not limited to [PF6]-,
[BF4]-,
[B(C6H5)4] , [I3] , [Br3] , [BI4] , [OTf] , or picrate.
First Dinucleo~hile
The first dinucleophile can be any of the following:
(a) an aromatic structure having up to 6 conjugated rings which may be
heteroaryl having C, N or S atoms, and which may include C(CH3)2,
S02, S-S, or CO or C1_6 alkyl in the structure or as substituents;
(b) a linear or branched alkyl group having 3 to 12 carbons which may
contain S;
(c) a cyclic alkyl having from 5 to 12 carbons; or
(d) a heterocyclic alkyl having C, S, or N;
having OH, SH or NH at the two nucleophilic positions. When NH is present at
the nucleophilic position, the N may comprise part of a ring structure.
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Examples of the first nucleophile include, but are not limited to the
following:
HO-(C6H4)2-OH
HO-(C6Ha)C(CHs)2(C6Ha)-OH
HO-(C6Ha)SOZ(C6Ha)-OH
HO-C(C6H4)4-OH
HO-CloHB-OH
HO-C loH6-S2-C ioH6-OH
HO-(C6H4)CO(C6H4)-OH
HS-(CH2)2S(CH2)2SH
HS-(CH2)20(CH2)2SH or
(HNCSH9)(CH2)s(CsH9NH).
The Second Dinucleophile
The second dinucleophile may be the same as or different from the first
dinucleophile, and can be any of the following:
(a) an aromatic structure having up to 6 conjugated rings which may be
heteroaryl having C, N or S atoms, and which may include C(CH3)2,
S02, S-S, or CO or C1_6 alkyl in the structure or as substituents;
(b) a linear or branched alkyl group having 3 to 12 carbons which may
contain S;
(c) a cyclic alkyl having from 5 to 12 carbons; or
(d) a heterocyclic alkyl having C, S, or N;
having OH, SH or NH at the two nucleophilic positions. When NH is present at
the nucleophilic position, the N may comprise part of a ring structure.
Examples of the second dinucleophile include, but are not limited to the
following:
HO-(C6H4)2-OH
HO-(C6Ha)C(CH3)2(C6Ha)-OH
HO-(C6Ha)S02(C6Ha)-OH
HO-C(C6H4)4-OH
HO-CloHg-OH
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HO-C loH6-S2-C ioH6-OH
HO-(C6H4)CO(C6H4)-OH
HS-(CH2)2S(CH2)2SH
HS-(CH2)20(CH2)2SH or
(HNCSH9)(CH2)3(C5H9NH).
Preparation of a Linear Bimetallized Aryl Compound
By reacting a first dinucleophile with a substituted benzene metallized
electron-withdrawing complex, a linear bimetallized aryl compound is formed.
The ratio of the first dinucleophile to the substituted benzene metallized
electron-withdrawing complex can range from about 1:1 to about 1:5 during the
reaction. Both nucleophilic sites on the first dinucleophile react with a halo-
or
nitro-substituted site of the substituted benzene to form a bond. As a result,
two
substituted benzene metallized electron-withdrawing complexes are bound to
each
first dinucleophile by an ether, thioether or amine bond, for nucleophilic
sites
having -OH, -SH, or -NH, respectively. Thus, reactants are consumed in a ratio
of
1:2. At reactant ratios less than 1:2, the yield of product will be reduced.
At
reactant ratios above 1:2, yield will be high relative to initial quantity of
the first
dinucleophile, but unreacted substituted benzene metallized electron-
withdrawing
complex will remain.
In the reaction of the first dinucleophile with the substituted benzene
metallized electron-withdrawing complex, a counter ion to each substituted
benzene
metallized electron-withdrawing complex is present, as discussed above. The
product of this reaction is a linear bimetallized aryl compound, which may be
an
ether, thioether or amine. Reaction conditions in the formation of this
product are
discussed in the prior art, for example, Abd-El-Aziz et al. , J. Chem. Soc.
Dalton
Trans. 1995:3375 and Abd-El-Aziz et al., Organometallics 1994;13:374-384.
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The linear bimetallized aryl compound comprises the first nucleophile bound
at both nucleophilic sites to the benzene ring of the benzene ring by an
ether,
thioether or amine linkage. The linear bimetallized aryl compound now contains
the metallized electron-withdrawing group, for example a cyclopentadienyl
iron,
complexed via the metal group, in this example iron, to the benzene ring.
Preparation of a Cyclic Bimetallized Ar, l~ Compound
To prepare a cyclic bimetallized aryl compound, the linear bimetallized aryl
compound is reacted with a second dinucleophile.
Each linear bimetallized aryl compound has two substituent groups remaining
which are open to nucleophilic attack, one on each of the two benzene rings
complexed with the metals. The second dinucleophile is of an appropriate size
to
conduct concurrent nucleophilic substitution at these two remaining
substituent
groups of the benzene rings. This reaction closes the linear polymer to form a
cyclic
bimetallized aryl compound.
The ratio of second dinucleophile to linear bimetallized aryl compound can
range from about 0.5 :1 to about S :1 during the reaction. The reactants are
consumed in a ratio of 1:1, and if insufficient quantities of the second
dinucleophile
are present, the yield will be low, relative to the amount of linear
bimetallized aryl
compound used. If excess quantities of the second dinucleophile are used, the
yield
will be high and unreacted quantities of the second dinucleophile will remain.
The formation of the cyclic bimetallized aryl compound occurs in the presence
of a base, for example, but not to be construed as limiting, metal carbonates
such as
potassium carbonate, sodium carbonate, sodium hydride, sodium t-butoxide,
potassium t-butoxide.
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The reaction is conducted in any appropriate organic solvent, for example but
not limited to dimethylformamide, tetrahydrofuran, dimethylsulphoxide,
dimethylformamide/tetrahydrofuran, dichloromethane, acetone, etc.
The reaction temperature can range from about 15 ° C to about 70
° C, and the
reaction may be conducted for about 5 to about 30 hours. The reaction occurs
under
nitrogen or argon atmosphere.
The cyclic bimetallized aryl compound comprises the first nucleophile bound
at both nucleophilic sites to benzene rings by an ether, thioether or amine
linkage
and also contains the second nucleophile bound at both nucleophilic sites to
the
benzene rings by an ether, thioether or amine linkage, at the formerly halo-
or
nitro-substituted carbons. The cyclic bimetallized aryl compound also contains
the
electron-withdrawing group, for example a cyclopentadienyl iron, complexed via
the metal group, in this case iron, to both benzene rings.
To isolate and purify the cyclic bimetallized aryl compound, after conducting
the reaction, the resulting solution can be poured into an aqueous solution of
about 5%
to about 20% strong acid (v/v) to precipitate the cyclic bimetallized aryl
compound.
The acid can be hydrochloric or sulfuric, for example.
An aqueous solution of counter ion salt may also be used to precipitate the
cyclic bimetallized aryl compound. The counter ion may be, for example but not
limited to [PF6]-, [BF4]-, [B(C6H5)4]-, [I3]-, [Br3]-, [BI4]-, [OTf]-, or
picrate. An
appropriate salt of the counter ion, such as the ammonium salt, is used.
The precipitated cyclic bimetallized aryl compound can then be collected,
washed and dried as required or further purified according to standard
methodology.
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Preparation of a Cyclic Ar l~ Compound
To prepare the cyclic aryl compound, the metallized electron-withdrawing
group is removed from both benzene rings of the cyclic metallized aryl
compound
formed as described above. The metallic portion of the metallized electron-
withdrawing moiety is thereby de-complexed to the benzene ring.
Any acceptable means of removal of the metallized complex to the benzene
ring may be used, such as, but not limited to, photolytic demetallation,
thermolysis
or electrolysis.
In the case of photolytic demetallation, the cyclic metallic aryl compound is
dissolved in an organic solvent, for example acetonitrile, dimethylformamide,
acetone, dimethylsulphoxide, or dichloromethane/acetonitrile mixture.
The solvent mixture is then irradiated with radiation in the UV-visible range,
such as a Xenon lamp for a period of time ranging from about 2 to about 10
hours
appropriate to achieve demetallation.
Isolation and Purification of the Cyclic Aryl Compound
Subsequently, the cyclic aryl compound produced is extracted from the
solution, for example by solvent evaporation followed by further organic
solvent
extraction, such as by a chloroform/nitromethane mixture, dichloromethane,
acetone,
dimethylformamide, or dimethylsulphoxide extraction. The cyclic aryl compound
could then be washed and filtered according to standard methodology
The by-products of demetallation can be separated from the cyclic aryl
compound using standard methodology, such as column chromatography, using
hexane to elute such by-products as ferrocene, followed by chloroform or ethyl
acetate
elution of the cyclic aryl compound.
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Utility
The cyclic aryl compounds formed according to the invention are useful as
macrocycles in studies of conformational analysis. Specifically, guest-host
chemistry
involves the recognition of the "guest" molecule by the "host" molecule. The
rigidity
of the macrocyclic "host" allows for the molecular recognition of the "guest"
molecule. A given macrocycle only complexes to certain molecular
conformations.
Thus, for a guest to become complexed, it must possess the correct
conformation.
The compounds of the present invention readily undergo ring-opening
polymerization to yield a linear polymer. This is desirable because the
resulting
polymers are of high molecular weight and low polydispersity. Polydispersity
is an
indication of the amount of branching in a polymer and a low polydispersity
indicates
minimal branching. The less branching in a polymer, the stronger it is.
Compounds of the present invention are also appealing due to the rigidity and
stability of the structures, which reduces conformational freedom. The
molecules
may be used in chiral recognition, by introducing a chiral center into the
molecule to
allow for identification of other chiral species through joining of the two
molecules
(complexation). Chiral recognition is beneficial for separating enantiomeric
mixtures
which cannot be separated using traditional methods, such as GC, HPLC, or
column
chromatography. Introducing a chiral center into a macrocycle of the present
invention which possesses an appropriate cavity size, would enable separation
of
enantiomeric mixtures. These macrocycles may be used in selective complexation
or
as molecular receptors.
Compounds of the present invention may be useful as catalysts at high
temperatures or in hostile environments, since the aromatic sub-units cause
the
macrocycle to be rigid and strong, thus enabling them to withstand harsh
environments. As a harsh environment catalyst, the molecule would speed up
reactions in environments in which other catalysts do not survive.
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Examples
Examples are provided which describe particular embodiments of the
invention. The examples are not to be construed as limiting. The invention
encompasses such modifications to the exemplified embodiments as would occur
to
one skilled in the art.
Example 1
A first dinucleophile, HO-(C6H4)2-OH, is combined with 1,3-
dichlorobenzene cyclopentadienyl iron (II) hexafluorophosphate in a ratio of
1:2 to
form a linear bimetallic aryl ether. The linear bimetallic aryl ether (0.5
mmol) is
combined with 0.5 mmol of HO-(C6H4)2-OH (the second dinucleophile), 2.5 mmol
of potassium carbonate (K2C03), and 10 mL of dimethylformamide (DMF) in a 25
mL round bottom flask. The solution is then reacted at room temperature or
refluxed
at 65 °C under a nitrogen atmosphere for 20 to 24 hours.
The solution is poured into 50 mL of 10% (v/v) hydrochloric acid causing the
cyclic bimetallic aryl ether to precipitate out of solution. Aqueous ammonium
hexafluorophosphate (NH4PF6) is added to further aid precipitation of the
product.
The product is then collected using a glass crucible and washed with several
portions
of distilled water. After drying for several hours the product is rinsed with
a small
amount of diethyl ether, and is allowed to dry. The cyclic bimetallic aryl
ether so
formed is illustrated below as Formula I-1.
U
Formula I-1
()
~p e* ~' Fe+~p
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In a 50 mL Pyrex photolysis tube, 0.25 mmol of the cyclic bimetallic aryl
ether is dissolved in 40 mL of a dichloromethane/acetonitrile (CH2Cl2/CH3CN)
mixture. This solution is then irradiated with a xenon lamp for 5-6 hours to
achieve
demetallation by photodecomposition. After this time, the solvent mixture is
evaporated from the product leaving a black solid, which is then extracted
with a
chloroform/nitromethane (CHCl3/CH3CN) mixture and washed with distilled water.
The organic layer is then dried with magnesium sulfate, gravity filtered into
a 250 mL
round bottom flask, and the solvent is evaporated off.
The cyclic aryl ether is then separated from the by-products of photolysis via
column chromatography. Ferrocene, one of the by-products, is eluted from the
column with hexane, followed by the elution of the cyclic aryl ether using
chloroform
(CHC13) and/or ethyl acetate (CH3COOCHZCH3). The cyclic aryl ether product of
Example 1 is illustrated below as Formula II-1.
Formula II-1
Figure 1 represents the ORTEP plot of the product formed in Example 1,
Formula II-1.
X-ray crystallography provides structural proof for the presence of the
compound of Formula (II-1). Crystal data: colourless crystals from CHC13,
crystal
dimensions 0.40 x 0.20 x 0.20 mm, monoclinic. space group P2~c.a = 6.0546(16),
h =
16.093(2), c = 13.514(4) A, V= 1314.7(6)A , Z = 4, ~. = 0.07 mm ', 1814
reflections
measured, 1736 unique, R~,, = 0.058, R = 0.050, CCDC 182/696.
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Example 2
The following products are prepared according to the method of Example 1.
I~3
t) ~ C O
CH3 Formula I-2
Q O
to GP e* e~Gp
H3
a C U
C$3 Formula II-2
O ~ ~ n
SCHEME 1
Scheme 1 outlines the reaction sequence employed for the preparation of
cyclic bimetallic aryl ethers of Formula I-1 and Formula I-2, and cyclic aryl
ethers of
Formula II-1 and Formula II-2 according to Examples 1 and 2.
/ \ ~ / \ X / \ o
HO ~ ~ X / ~ OH
CI ~ ~ _
2 X .. direct Dond ~ Ct
Fg- CI
X a C
U .. L. ~ ~ s ..l ..
t
U
~, 5 + ~
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Q / \ X / \ O
/ \ / O /'\ X ~~ \ O
/ \ / \ a I ~~ / \ / \
~~- Fe- ~ - /
__ ._ o / \ ~ \ o
CU U
6. 7
In this scheme, the initial reaction of complex 1 and dinucleophile 2 or 3 in
a
2:1 molar ratio is carried out in order to obtain the bimetallic complex (4 or
5) in high
yield. The reaction of 4 or 5 with dinucleophile 2 in an equimolar ratio leads
to the
formation of complexed cyclic aryl ethers Formulae I-1 and I-2 (denoted as 6
and 7)
in yields of 86 and 89%, respectively.
The rigid nature of these complexed macrocycles introduces both cis- and
traps-orientations of the cyclopentadienyl iron (CpFe+) moieties attached to
the arene
ring. The presence of two different cyclopentadienyl (Cp) resonances as well
as a
complex aromatic region in the 1H NMR spectra indicates a mixture of both cis
and
traps products present. Based on the integration of the respective Cp
resonances, it
was determined that for complex of Formula I-1 the ratio of cis to traps
product was
3:1 while it was 1:1 for the complex of Formula I-2. The major structure was
predicted to be traps based on previous findings.
Photolytic demetallation was implemented to allow for the recovery of the free
organic macrocycles of Formulae II-1 and II-2 (here indicated as 8 and 9) in
yields of
64 and 58%, respectively, which may be attributed to the poor solubility of
these
macrocyclic materials in most organic solvents. The ~ H NMR spectra indicated
the
symmetric nature of these materials. It was noted that a triplet was present
at a rather
high field chemical shift of 8 5.6 (8) or 6.2(9) which was attributed to the
inner-ring
protons of the benzene ring. This shift is explained by the large diamagnetic
shielding
caused by the two adjacent biphenyl rings on the inner-ring protons. This
observation
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is in accordance with similar cyclic aryl ether NMR shifts Unequivocal proof
of the
structure of 8 was obtained by an X-ray crystallographic study, as discussed
above.
Single crystals suitable for X-ray analysis were obtained by slow evaporation
of a chloroform solution of the cyclic aryl ether at room temp. Rigidity
imparted in
the structure by the biphenyl and benzene rings of the compounds formed
according
to scheme 1. The biphenyl groups of the macrocycle are separated by 5.2 A
while the
diagonal distance of oxygen atoms was found to be 10.9 A.
Example 3
The following products are prepared according to the method of Example 1 with
the
appropriate selection of X~, X3, n~ and n3.
o Q
Formula I-3
a
Fe+C
P
Formula II-3
Example 4
The following products are prepared according to the method of Example 1 with
the
appropriate selection of X1, X3, nl and n3.
CA 02259721 1999-O1-20
-19-
Formula I-4
$ ~ r _
Cp~e+ ~---~ ~----t Fe+~p
Formula II-4
15 SCHEME 2
Scheme 2 illustrates the sequence of reactions may be employed with the
(dichlorobenzene)CpFe+ complex (10) and dinucleophiles containing both
aliphatic
and aromatic bridges.
C1 ~ O
I \
~~ Ct I ~~
I I CI CI
Fe' ; HO / ~ pH -.- Fe. Fa'
~~, 11
_,
U
,o
Hx~z~xH
tsx.s.z.o
i4x.z.s
p / \ o w ~ o / \ o
w
x
r''- I U ~.rX
Fe' Fe'
?~x_s,z~o
78 X w
U
15X-S.z=O
~~Xaz~S
CA 02259721 1999-O1-20
-20-
In this scheme, cyclic bimetallic aryl ether compounds 15 and 16
(corresponding to Formulae I-3 and I-4, respectively) and cyclic aryl ether
compounds
17 and 18 (corresponding to Formulae II-3 and II-4, respectively) having both
oxygen
and sulfur bridges can be prepared. Unlike the rigid macrocycles prepared in
Scheme
1 (Examples 1 and 2), these structures have no inner ring protons and as a
result no
high field chemical shifts were observed.
Specific examples of compounds formed by this process are shown in
Examples 3 and 4. For each example, the cyclic bimetallic aryl ether and the
(organic) cyclic aryl ether are illustrated.
Example 5
The following products are prepared according to the method of Example 1 with
the
appropriate selection of X~, X3, nl and n3.
Formula I-5
~/
2s Cp+Fe Fe+Cp
CA 02259721 1999-O1-20
-21 -
0
o~ Eo,~,~,
00 0 0
Example 6
The following products are prepared according to the method of Example 1 with
the
appropriate selection of XI, X3, nl and n3. Figure 2 represent the ORTEP plot
of the
compounds shown below as Formula II-6.
o o'
Formula I-6
Cp+Fe Fe~Cp
~\ f~
~ Formula II-6
to U
Example 7
The following products are prepared according to the method of Example 1 with
the
appropriate selection of XI, X3, n~ and n3.
CA 02259721 1999-O1-20
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S S
n Q Formula I-7
p ~ O
Cp+Fe S S Fe+Cp
-
Formula II-7
W Co>
Example $
The following products are prepared according to the method of Example 1 with
the
appropriate selection of X1, X3, nl and n3.
25 '~""~ ~' N ~ Formula I-8
N CH2
CpFe+ Fe+Cp
CA 02259721 1999-O1-20
- 23 -
Formula II-8
s
Example 9 N~~~H2
3
The following products are prepared according to the method of Example 1 with
the
appropriate selection of X1, X3, nl and n3.
Q
Formula I-9
1
N CHI N
1 s C~~~t ~ F~+~~
I I
~ ~ 0 Formula II-9
N GH2 ~l
~ 3
Example 10
The following products are prepared according to the method of Example 1 with
the
appropriate selection of X1, X3, nl and n3.
CA 02259721 1999-O1-20
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N
3
Formula I-10
+~
~P a Fe+Cp
N
Formula II-10
n Co
v
Example 11
The following products are prepared according to the method of Example 1 with
the
appropriate selection of XI, X3, n~ and n3.
Q G
~H3 ( Formula I-11
~H2 3 ~ +
~p e+ Fe Cp
CA 02259721 1999-O1-20
- 2s -
CH3
s
Q C 0
CH3 Formula II-11
N CH2 N
l0 3
Example 12
The following products are prepared according to the method of Example 1 with
the
1 s appropriate selection of X~, X3, nl and n3.
O a
Formula I-12
o ~ ~ a
2s CpFe+ Fe~'Cp
CA 02259721 1999-O1-20
-26-
Formula II-12
°? o o ~°
Example 13
The following product is prepared according to the method of Example 1 with
the
appropriate selection of X1, X3, nl and n3.
Cp Fey --- ~ Fe+Cp
Formula I-13
(: ~ ,Jr-
!I:
All publications cited herein are incorporated by reference. Various
modifications may be made without departing from the invention. It is
understood
that the invention has been disclosed herein in connection with certain
examples and
embodiments. However, such changes, modifications or equivalents as can be
used
by those skilled in the art are intended to be included. Accordingly, the
disclosure is
to be construed as exemplary, rather than limiting, and such changes within
the
principles of the invention as are obvious to one skilled in the art are
intended to be
included within the scope of the claims.
