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We derive theoretical models for the structures of randomly hyperbranched polymers in solution, and test them against computer simulations. The models are based on the same basic approach: Building a structure by the random assembly of “simple units,” which may be monomers, linear chains, or larger branched species. Comparisons to simulation reported here show that the conformations of hyperbranched species, i.e., their radii of gyration and full density profiles, are accurately described by this approach. These stringent tests complement previous tests against experiment. We include the effects of solvent quality at the mean-field level. Our model works best for hyperbranched structures, but also reproduces very well the simulated density profiles of dendrimers. The models reported here provide a simple, but realistic, picture of the physical influences that affect the conformations of hyperbranched species. [ABSTRACT FROM AUTHOR]

The C–C bond fragmentation of carbocycles has been developed as a new method for the divergent synthesis of dendrimers. The scope of this reaction was examined with the preparation of six first generation dendrimers from structurally diverse and readily available fragmentation precursors. By pairing the fragmentation with a thio-Michael reaction, the preparation of a [G4]-ene24dendrimer has been achieved. [ABSTRACT FROM AUTHOR]

A series of two-dimensional non-traditional carbon materials employing three-membered ring or four-membered ring as building blocks were systematically investigated by theoretical calculations in searching of highly conductive metallic carbon materials. It was found all the studied two-dimensional systems have metallic nature. The three-membered ring derivatives are not kinetically stable, and present of trap-like bands. While the four-membered ring systems of C4-8 and its derivatives containing triple bonds are kinetically stable, which provide a new choice of synthesizing two-dimensional carbon materials with metallic nature towards the application in the all carbon electronic circuits. [ABSTRACT FROM AUTHOR]