Structural Defects in Polyallylcarbosilane Dendrimers and Their PolyolDerivatives Characterized by NMR and MALDI-TOF Mass Spectrometry

0343150 - ÚCHP 2011 RIV US eng J - Journal Article
Krupková, Alena - Čermák, Jan - Walterová, Zuzana - Horský, Jiří
Structural Defects in Polyallylcarbosilane Dendrimers and Their PolyolDerivatives Characterized by NMR and MALDI-TOF Mass Spectrometry.
Macromolecules. Roč. 43, č. 10 (2010), s. 4511-4519. ISSN 0024-9297. E-ISSN 1520-5835
R&D Projects: GA MŠMT(CZ) LC06070
Institutional research plan: CEZ:AV0Z40720504; CEZ:AV0Z40500505
Keywords : carbosilane dendrimers * maldi-tof ms * structural defects
Subject RIV: CC - Organic Chemistry
Impact factor: 4.838, year: 2010

A series of polyallylcarbosilane dendrimers and carbosilane-based dendritic polyols up to third generation was analyzed by means of MALDI-TOF MS and multinuclear NMR to determine the character, origin, and number of structural defects. Several side reactions accompanying hydrosilylation, from which isomerization of terminal double bonds was the most abundant, were detected during the synthesis of carbosilane skeleton. Despite increased steric hindrance, internal double bonds react in subsequent addition reactions. Depending on the synthetic sequence applied, the retained reactivity of the internal double bonds can lead either to suppression of the defect in the next generation or to creation of more significant defects such as dendrimer dimers. Hydroboration of allyl groups using dicyclohexylborane proceeded with near quantitative conversion; a small amount of hydrolysis accompanying the following oxidation step producing nonreactive alkyl groups at the periphery was detected.
Permanent Link: http://hdl.handle.net/11104/0005897