Virgil Percec

Bio: Virgil Percec is an academic researcher from University of Pennsylvania. The author has contributed to research in topics: Polymerization & Radical polymerization. The author has an hindex of 101, co-authored 798 publications receiving 42465 citations. Previous affiliations of Virgil Percec include University of California, Berkeley & University of Ulm.

Synthesis and Structural Analysis of Two Constitutional Isomeric Libraries of AB2-Based Monodendrons and Supramolecular Dendrimers

Abstract: The synthesis and structural analysis of two constitutional isomeric libraries of self-assembling AB2 monodendrons based on 3,4- and 3,5-disubstituted benzyl ether internal repeat units containing four different first generation monodendrons, ie, 3,4,5-tris(n-dodecan-1-yloxy)benzyl ether, 3,4-bis(n-dodecan-1-yloxy)benzyl ether, 3,4,5-tris[p-(n-dodecan-1-yloxy)benzyloxy]benzyl ether, and 3,4-bis[p-(n-dodecan-1-yloxy)benzyloxy]benzyl ether, on their periphery are described Regardless of the repeat unit on their periphery, the first three or four generations of the 3,4-disubstituted series of monodendrons self-assemble into spherical supramolecular dendrimers that self-organize into a Pm3n 3-D cubic lattice while the same generations of the 3,5-disubstituted series of monodendrons self-assemble into cylindrical supramolecular dendrimers that self-organize into a p6mm hexagonal columnar 2-D lattice The internal repeat unit of the monodendrons determines the shape of the supramolecular dendrimers However

Arenesulfonyl Halides: A Universal Class of Functional Initiators for Metal-Catalyzed “Living” Radical Polymerization of Styrene(s), Methacrylates, and Acrylates†

Abstract: The complex Cu(I)Cl/4,4‘-dinonyl-2,2‘-bipyridine (bpy9) catalyzes via a redox process the homogeneous “living” radical polymerization of styrene(s), methacrylates, and acrylates initiated with a variety of functional phenylsulfonyl chlorides Polymers with narrow molecular weight distribution and molecular weights close to the theoretical ones are obtained from these three classes of monomers Kinetics of propagation and initiation were performed with selected substituted phenylsulfonyl chlorides and with their monoadducts to monomer Polymerizations follow first-order kinetics internally in monomer and externally in Cu(I)Cl while initiation is first order internally in initiator and in Cu(I)Cl concentrations A catalyst concentration dependence of the optimum bpy9/Cu(I)Cl ratio which yields the largest rate constant of polymerization was observed The apparent rate constants of propagation corrected for catalyst concentration are in the order: methacrylates > styrene > acrylates This inversion from the

From structure to function via complex supramolecular dendrimer systems.

Abstract: This tutorial review summarizes strategies elaborated for the discovery and prediction of programmed primary structures derived from quasi-equivalent constitutional isomeric libraries of self-assembling dendrons, dendrimers and dendronized polymers. These libraries demonstrate an 82% predictability, defined as the percentage of similar primary structures resulting in at least one conserved supramolecular shape with internal order. A combination of structural and retrostructural analysis that employs methodologies transplanted from structural biology, adapted to giant supramolecular assemblies was used for this process. A periodic table database of programmed primary structures was elaborated and used to facilitate the emergence of a diversity of functions in complex dendrimer systems via first principles. Assemblies generated by supramolecular and covalent polymer backbones were critically compared. Although by definition complex functional systems cannot be designed, this tutorial hints to a methodology based on database analysis principles to facilitate design principles that may help to mediate an accelerated emergence of chemical, physical and most probably also societal, political and economic complex systems on a shorter time scale and lower cost than by the current methods. This tutorial review is limited to the simplest, synthetically most accessible self-assembling minidendrons, minidendrimers and polymers dendronized with minidendrons that are best analyzed and elucidated at molecular, supramolecular and theoretical levels, and most used in other laboratories. These structures are all interrelated, and their principles expand in a simple way to their higher generations.