Abstract
Although oligosilanes containing highly coordinate silicon atoms have attracted current interests due to their novel properties, their reactivities remain unclear. We present here the syntheses, structures, and reactivities of the highly coordinate monosilane and disilanes bearing dithiocarboxylato ligands or carboxylato ligands. A disilane and a monosilane bearing dithiocarboxylato ligands were synthesized by the reaction of potassium 2,4,6-trimethyldithiobenzoate with 1,1,2,2-tetrachloro-1,2-dimethyldisilane and dichlorodiphenylsilane, respectively. X-ray crystallographic analysis of the disilane revealed some intramolecular interactions between a sulfur atom of thiocarbonyl groups and a silicon atom. Silicon atoms of the disilane were found to be in heptacoordination state. Similarly, the silicon atom of the monosilane is in hexacoordination state. Their spectral data revealed that some of these intramolecular interactions are maintained in solution. Reaction of the disilane with excess amount of elemental sulfur gave a compound with an adamantane-type framework composed of silicon and sulfur atoms in 85% yield. A disilane bearing carboxylato ligands was synthesized by the reaction of 2,4,6-trimethylbenzoic acid with 1,1,2,2-tetrachloro-1,2-dimethyldisilane and triethylamine. In the disilane, intramolecular interactions between an oxygen atom of carbonyl groups and a silicon atom was observed. Theoretical calculations on the model compounds of these highly coordinate organosilicon compounds will also be reported.
