Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Organic compound containing
Reexamination Certificate
2001-06-22
2004-09-21
Mullis, Jeffrey (Department: 1711)
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Organic compound containing
C502S158000, C502S172000, C502S402000
Reexamination Certificate
active
06794327
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention is generally directed toward molecular structures that are synthesized by cross-linking the peripheral surface of dendritic molecules. These cross-linked molecules are believed to be spherical in geometry or structure. The severing or cleaving of labile bonds within the dendritic molecule results in a spherical, cross-linked shell molecule that can encapsulate or entrap smaller molecules. Accordingly, the present invention is directed toward these spherical shell molecules, including those structures that contain smaller molecules within their structure, as well as a process for making the spherical shell molecules.
BACKGROUND OF THE INVENTION
Dendrimers are highly branched macromolecules formed by successive reactions of polyfunctional monomers around a core. Accordingly, as dendrimers grow from their core, their number of branches and terminal end groups increase, thereby increasing the density of these molecules at their peripheral surface.
Dendrimers are distinguishable from polymers because they are non-linear, hyper-branched structures that are synthesized in iterative fashion. The monomers from which they are constructed can generally be defined as AB
n
monomers, where n is usually 2 or 3, rather than the standard AB monomers, which produce linear polymers. Accordingly, each iteration of step-wise synthetic growth generally requires twice the number of monomers used in the previous iteration in the case of an AB
2
monomer, or three times the number of monomers in the case of an AB
3
monomer. The layer of monomers added in each iteration is called a generation. The ultimate generation, or that generation farthest from the core, produces the periphery of the molecule.
Because dendrimers are produced in iterative fashion, they can be synthesized to very high molecular weight molecules with narrow molecular weight distributions. Moreover, the nature of each generation can be controlled by controlling the type of monomer employed including the periphery or end groups.
Based on the foregoing, and the relative novelty of dendritic structures, the present invention furthers the art by making advancements in the modification of dendrimer structures, especially in their ability to act as, or produce, a shell to entrap smaller molecules.
SUMMARY OF INVENTION
It is therefore an object of the present invention to provide a core dendrimer having a cross-linked peripheral surface.
It is another object of the present invention to provide a molecule within another cross-linked shell structure, where the two molecules are not covalently or ionically bonded to each other.
It is another object of the present invention to provide a cross-linked hollow shell structure.
It is another object of the present invention to provide a supramolecular structure that allows the flow of small molecules into and out of the central core.
It is another object of the present invention to provide a supramolecular structure capable of entrapping smaller molecules.
It is another object of the present invention to provide a supramolecular structure having a cross-linked surface or peripheral porosity sufficient to entrap smaller molecules.
At least one or more of the foregoing objects, together with the advantages thereof over the known art relating to dendritic molecules and supramolecular structures, which shall become apparent from the specification that follows, are accomplished by the invention as hereinafter described and claimed.
The present invention therefore provides a supramolecular structure produced by the process comprising: reacting a multi-generation dendrimer with a monomer, where the dendrimer comprises a core molecule, a plurality of interior generations spherically disposed around the core molecule and an outermost generation comprising a plurality of dendritic branches having terminal groups sufficiently reactive to undergo addition or substitution reactions, where the monomer introduces a labile bond and at least one cross-linkable moiety to the terminal groups of each dendritic branch, and where the cross-linkable moiety is bonded to the terminal group via the labile bond; cross-linking the cross-linkable moieties of adjacent dendritic branches; and cleaving the labile bonds, thereby freeing the dendrimer and forming a molecule encapsulated within a cross-linked shell molecule.
The present invention further provides a process for producing a supramolecular structure comprising: reacting a multi-generation dendrimer with a monomer, where the dendrimer comprises a core molecule, a plurality of interior generations spherically disposed around the core molecule and an outermost generation comprising a plurality of dendritic branches having terminal groups sufficiently reactive to undergo addition or substitution reactions, where the monomer introduces a labile bond and at least one cross-linkable moiety to the terminal reactive groups, and where the cross-linkable moiety is bonded to the terminal reactive group via the labile bond; cross-linking the cross-linkable moieties of adjacent dendritic branches; and cleaving the labile bonds, thereby freeing the dendrimer and forming a molecule encapsulated within a cross-linkable shell molecule.
The present invention further provides a supramolecular structure produced by the process comprising: reacting a multi-generation dendrimer with a monomer, where the dendrimer comprises a core molecule, a plurality of interior generations spherically disposed around the core molecule and an outermost generation comprising a plurality of dendritic branches having terminal groups sufficiently reactive to undergo addition or substitution reactions, where the monomer introduces a labile bond and at least one cross-linkable moiety to the terminal groups, and where the cross-linkable moiety is bonded to the terminal group via the labile bond; crosslinking the cross-linkable moieties of adjacent dendritic branches; cleaving the labile bonds, thereby freeing the dendrimer and forming a molecule encapsulated within a cross-linked shell molecule; and degrading and removing the free dendrimer, thereby producing a intramolecularly cross-linked spherical hollow shell structure.
A process for producing a supramolecular structure comprising: reacting a multi-generation dendrimer with a monomer, where the dendrimer comprises a core molecule, a plurality of interior generations spherically disposed around the core molecule and an outermost generation comprising a plurality of dendritic branches having terminal groups sufficiently reactive to undergo addition or substitution reactions, where the monomer introduces at least one labile bond and a cross-linkable moiety to the terminal group of each dendritic branch, and where the cross-linkable moiety is bonded to the terminal group via the labile bond; cross-linking the cross-linkable moieties of adjacent dendritic branches; cleaving the labile bonds, thereby freeing the core dendrimer and forming a molecule encapsulated within a cross-linked shell molecule; and degrading and removing the free dendrimer, thereby producing a intramolecularly cross-linked spherical hollow shell structure.
The present invention also provides a supramolecular structure comprising a dendrimer having a cross-linked peripheral surface; a supramolecular structure comprising a hollow cross-linked shell molecule; and a supramolecular structure comprising a dendrimer and a cross-linked shell molecule spherically disposed about the dendrimer, wherein the dendrimer and the cross-linked shell molecule are not ionically or covalently bonded together.
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Niu Yanhui
Rinaldi Peter L.
Tessier Claire A.
Youngs Wiley J.
Mullis Jeffrey
Roetzel & Andress
The University of Akron
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