INOR 22-Organometallic chemistry of a guanidine-substituted tris(trimethylsilyl)methyl ligand

The organometallic chemistry of the silicon-substituted tris(trimethylsilyl)methide ('trisyl') anion, [C(SiMe3)3]–, has been enhanced through the incorporation of additional donor substituents (L) able to chelate to the metal centre. To date, such species of general formula [C(SiMe3)n(SiMe2L)3-n]–, have been restricted to those in which a four- or five-membered metallacycle are formed, illustrated for L = NMe2 (A) and 2-pyridyl (B), respectively. We anticipated that upon chelation to a metal, the guanidyl-substituted derivative, HC(SiMe3)2(SiMe2hpp) (hppH = 1,3,4,6,7,8,-hexahydro-2H-pyrimido[1,2-a]pyrimidine) would enhance the bulk of these already sterically demanding ligands through formation of a six-membered metallacycle (C), and strong donation from the imine nitrogen would stabilize otherwise highly reactive organometallics. In this presentation we report some early results of the chemistry of this new addition to the family of substituted trisyl-ligands, focusing on their structural chemistry as determined by X-ray crystallography.