Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From carboxylic acid or derivative thereof
Reexamination Certificate
1999-08-31
2001-10-16
Acquah, Samuel A. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From carboxylic acid or derivative thereof
C528S271000, C528S298000, C528S494000, C528S503000, C524S261000, C524S366000
Reexamination Certificate
active
06303740
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates generally to self-organized polymolecular structures and in particular, to helical, tubular and needle-like structures formed by the association of amphiphilic tartaric acid derivatives and bipyridine compounds.
2. Description of the Related Art
Materials of defined morphologies, such as polymolecular tubular or helical structures, have many practical uses, including as vehicles for controlled-release drug delivery, as reinforcing material for high strength composites and as components of radar absorbing materials.
Currently known materials of defined morphologies include structures formed by molecular self-assembly of single molecular components such as amphiphiles (for example, phospholipids). Amphiphiles are compounds that have a hydrophobic portion and a hydrophilic portion. In an aqueous solution, the hydrophobic portions of adjacent molecules tend to congregate, thereby creating a polymolecular structure. For example, U.S. Pat. No. 5,290,960 to Singh describes tubular microstructures formed by the self-assembly of diacetylenic phospholipids. The technical utility of diacetylenic phospholipid-derived tubules for applications such as controlled release drug delivery has been demonstrated, but the practical usefulness of these materials is limited because of their high cost and poor shelf life.
Self organized structures have also been formed by the non-covalent interactions (such as hydrogen bonding) between complementary molecular building blocks. Such structures are described, for example, in the following publications, incorporated herein by reference: J. -M. Lehn, “Supramolecular Chemistry: Concepts and Perspectives” published by Verlag Chemie, Weinheim, pp 139-197, (1995); C. P. Lillya et al., “Linear Chain Extension Through Associative Terminii”, Macromolecules, 25, 2076-2080, (1993); R. P. Sijbesma et al., “Reversible Polymers by Quadruple Hydrogen Bonding”, Science, 278, 1601-1604, (1997); T. Kato, “A Liquid Crystalline Polymer Network Built by Molecular Self-Assembly Through Intermolecular Hydrogen Bonding”, Angew. Chem. Int. Ed. Engl., 33, 1644, (1994); C. M. Paleos and D. Tsiourvas, Angew. Chem. Int. Ed. Engl., 34, 1696-1711, (1995) and G. Whitesides et al., Non-covalent Synthesis, Acc. Chem. Res., 28, 1, 1995. Intermolecular hydrogen bonding between compounds containing pyridine groups and compounds containing carboxyl groups is described in the following patents and publications, incorporated herein by reference: U.S. Pat. No. 5,037,574 to Frechet et al; U.S. Pat. No. 5,139,696 to Frechet et al; Kihara et al, “Supramolecular Liquid-Crystalline Networks Built by Self-Assembly of Multifunctional Hydrogen-Bonding Molecules”, Chem. Mater., Vol 8, No. 4 (1996), pp 961-968; Kato et al, “Cooperation of Hydrogen Bonds for Mesophase Stabilization in Supramolecular Assemblies”, Chemistry Letters 1997, pp 1143-1144; Kihara et al, “Induction of a Cholesteric Phase via Self-Assembly in Supramolecular Networks Built of Non-Mesomorphic Molecular Components” Liquid Crystals, 1998, Vol. 24, No. 3, pp. 413-418; and Mallia et al “Photochemical Phase Transition in hydrogen-Bonded Liquid Crystals,” Chem. Mater 1999, 11, pp 207-208.
SUMMARY OF THE INVENTION
It is an object of this invention to provide a method to make polymolecular structures with inexpensive molecular building blocks.
It is a further object of this invention to exploit both the ability of amphiphiles to self-assemble by hydrophobic interactions to form microstructures and the ability of compounds having complementary hydrogen-bonding functional groups to self-organize to form supramolecular systems.
It is a further object of this invention to provide stable polymolecular structures having defined morphologies.
It is a further object of this invention to provide polymolecular structures wherein functional groups such as chromophoric functional groups, electrically-conducting functional groups, or a metal chelating groups are incorporated into the structure.
These and other object of the invention are accomplished by a composition comprising a self-organized polymolecular association of molecules of a 2,3 di-O-substituted tartaric acid compound and molecules of a bipyridyl compound. Helical, tubular or needle-like structures can be made by combining the tartaric acid compound and bipyridyl compound and heating the mixture so that the two components are mixed on a molecular level and interact to form self-organized polymolecular structures.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
In the present invention, materials with unique defined structural and morphological properties are formed by the noncovalent association of complementary monomers, specifically, tartaric acid derivatives and bipyridine compounds.
The tartaric acid derivative of the present invention is a tartaric acid compound that has been modified to give it an amphiphilic character by replacing the middle hydroxyl groups with hydrophobic moieties such as alkoxy groups. The substituted hydrophobic groups may also incorporate functional moieties such as chromophoric functional groups, electrically-conducting functional groups, metal chelating groups or polymerizable groups.
Examples of chromophoric functional groups include, but are not limited to, substituted azobenzene, stilbene, and biphenyl groups.
Examples of electrically-conducting functional groups include, but are not limited to cyanobenzene, furan, pyrrole and thiophene groups
Examples of metal-chelating groups, but are not limited to crown ethers, N-substituted crown ethers, and amine groups.
Examples of polymerizable groups include, but are not limited to methacryloyl, vinylbenzyl, dienyl, diacetylenic, and sulfhydryl groups.
In general, the tartaric acid derivative may be represented by the formula (1):
wherein R
1
, and R
2
are the same or different and are selected from the group consisting of
—H, wherein R
1
and R
2
are not both H
—(CH
2
)
a
—CH
3
, wherein a is an integer between 0 and 20,
—(CH
2
)
b
—X, wherein b is an integer between 0 and 20 and X is a polymerizable group,
—(CH
2
)
c
—X—(CH
2
)
d
—CH
3
, wherein c and d are integers between 0 and 20, wherein the sum of c and d is not greater than 20 and wherein X is as defined above,
—(CH
2
)
e
—X—(CH
2
)
f
—Y, wherein e and f are integers between 0 and 20, wherein the sum of e and f is not greater than 20, wherein X is as defined above, and wherein Y is a functional group selected from the functional groups consisting of a chromophoric functional group, and electrically-conducting functional group, and a metal chelating group,
—(CH
2
)
g
—Y—(CH
2
)
h
—X, wherein g and h are integers between 0 and 20, wherein the sum of g and h is not greater than 20, and wherein X and Y are as defined above,
—(CH2)
i
—X—(CH
2
)
j
—Y—(CH
2
)
k
—CH
3
, wherein i, j, and k are integers between 0 and 20, wherein the sum of i, j, and k is not greater than 20, and wherein X and Y are as defined above, and
—(CH
2
)
l
—Y—(CH
2
)
m
—X—(CH
2
)
n
—CH
3
, wherein l, m, and n are integers between 0 and 20, wherein the sum of l, m, and n is not greater than 20, and wherein X and Y are as defined above.
The tartaric acid derivative used in the present invention may be derived from the L-tartaric acid, D-tartaric acid, or DL tartaric acid. Preferably, the L-form is used because, as a byproduct of the wine industry, it is relatively inexpensive. The derivative may be formed by any method known in the art such as, for example, reacting N,N,N′N′-tetramethyl-tartaramide (commercially available starting material) with a substituted bromide in the presence of thallium ethoxide or sodium hydride in dimethylformamide (DMF) (preferred) and then hydrolyzing the substituted amide. This synthesis is represented by the following reaction scheme:
Because additional and expensive synthesis steps would be required to produce a tartaric acid derivative having different substituents for R
1
and R
2
, it is preferable that R
1
and R
2
be the same.
In the present invention, the tartari
Acquah Samuel A.
Karasek John J.
Ressing Amy L.
The United States of America as represented by the Secretary of
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