Preparation of dendritic carbosilanes containing ethynyl groups and dicobalt hexacarbonyl clusters on the periphery

Abstract

Dendritic carbosilanes have been prepared by the use of 2,4,6,8-tetramethyl-2,4,6,8-tetravinyl-2,4,6,8-tetrasila-1,3,5,7-tetraoxacyclooctane (CH 2CHMeSiO) 4 and 1,2-bis(triallylsilyl)ethane ((CH 2CHCH 2) 3SiCH 2) 2 as core molecules, diallylmethylsilyl groups ((CH 2CHCH 2) 2MeSi) as building blocks and bisphenylethynylmethylsilyl groups ((PhCC) 2MeSi) as terminating groups. The phenylethynyl-group-containing terminal generation is produced by the reaction of the chlorosilylated generation with lithium phenylacethylide. The reaction of dicobalt octacarbonyl Co 2(CO) 8 with phenylethynyl groups gave the corresponding phenylethynyl hexacarbonyl complexes (2Co 2(CO) 6·(PhCC) 2MeSidendimer) on the periphery. The yields of the prepared dendrimers with phenylethynyl terminal groups and their cobalt carbonyl complexes are obtained nearly quantitatively. They are characterized by the use of spectroscopic analyses ( 1H-, and 13C-NMR, UV and IR) as well as MALDI mass spectroscopy and elemental analysis.