Silsesquioxane Chemistry. 12 [1] Preparation and Complexation of a Novel Silsesquioxanyl Phosphine Ligand

The reaction of the monofunctional closo‐silsesquioxane silanol derivative Cy7Si8O12OH (3, Cy = c‐C6H11) with tris(dimethylamino)phosphine afforded the novel silsesquioxanyl phosphine ligand Cy7Si8O12OP(NMe2)2 (4) in virtually quantitative yield. The complexes [Cy7Si8O12OP(NMe2)2]2PtCl2 (5) and [Cy7Si8O12OP(NMe2)2]2Mo(CO)4 (6) were obtained in excellent yields upon treatment of 4 with (COD)PtCl2 (COD = 1, 5‐cyclooctadiene) and (NBD)Mo(CO)4 (NBD = norbornadiene), respectively. An attempted preparation of the bis(silsesquioxanyl)phosphine (Cy7Si8O12O)2P(NMe2) led to the formation of the known disiloxane derivative (Cy7Si8O12)2O (7), instead.