Synthesis of Organosilane and Organoborane Materials

An emerging area of research is the synthesis of main group organometallic compounds and polymers with a level of atomic precision comparable to organic natural products. Two efforts in organosilicon and organoboron compounds are described. Organosilanes are desirable synthetic targets for their potential optoelectronic properties and applications but limited synthetic options have restricted opportunities for exploring structure-property relationships. Low-energy absorption bands can be accessed in anti-conformations that maximize σ-conjugation but the conformational heterogeneity of linear oligosilanes contributes to broad absorption spectra. Cyclohexasilanes are a class of compounds with reduced degrees of conformational freedom that may show promise for maximizing σ-conjugation. The synthesis and optical characterization of two stereoisomers of a novel cyclosilane are described. The formation of silyl dianions (disilanides) was key to two steps of this synthesis and minor procedural changes to remove of volatile byproducts allowed crucial improvements to yield that could be broadly applicable to comparable disilanides. These isomers also showcase novel 1H NMR spectra with the first observations of long-range 4J ‘W-coupling’ in organosilanes normally associated with rigid strained polycyclic carbon compounds. In addition, an investigation of supramolecular, noncovalent interactions with lithium ions is described. Novel copolymers were prepared by radical copolymerization of 4-bromostyrene and BN 2-vinylnaphthalene, an organoborane monomer developed in the Klausen group. C–B side chains were oxidatively converted to hydroxyl groups. The 4-bromostyrene co-monomer is incorporated for its photoinitiated crosslinking capabilities. Thin films were prepared of these copolymers and the compatibility of oxidation and crosslinking processes were investigated in tandem