Synthesis of (pentamethylcyclopentadienyl)nitrosylmolybdenum complexes containing halide, methyl, or cyclopentadienyl ligands. Crystal structures of [MoMe(η-C5H5)(η-C5Me5)(NO)] and [{Mo(η-C5Me5)O(µ-O)}2]

Abstract

Treatment of the dihalogeno derivatives [{Mo(η-C₅Me₅)(NO)X(µ-X)}₂][X = Cl, (1a); Br, (1b); or I, (1c)] or [Mo(η-C₅Me₅)(NO)X₂(PPh₃)][X = Cl, (2a); Br, (2b); or I, (2c)] with Al₂Me₆ gives the halogenomethyl complexes [{MoMe(η-C₅Me₅)(NO)(µ-X)}₂](3a)–(3c) or [MoMe(η-C₅Me₅)(NO)X(PPh₃)](4a)–(4c) respectively. Dimers (3) react with PPh₃ to give monomers (4). Complex (1b) reacts with LiMe to give [MoMe₂(η-C₅Me₅)(NO)](5). Reactions of (1) or (3b) with Tl(C₅H₅) give the ‘20-electron’ mixed bis(cyclopentadienyl) complexes [Mo(η-C₅H₅)(η-C₅Me₅)(NO)Y][Y = Cl, (6a); Br, (6b); I, (6c); or Me, (7)]. The structure of complex (7)(crystal A) has been determined by X-ray diffraction methods. By accident, the structure of the first crystal examined (B) contained (7) and the oxo complex trans-[{Mo(η-C₅Me₅)O(µ-O)}₂](8) in an ordered mixture with a 2:1 molar ratio. Crystal A is orthorhombic, space group Pna2₁ with Z= 4 in a unit cell of dimensions a= 9.370(4), b= 12.322(5), and c= 13.301 (5)Å. Crystal B is monoclinic, space group P2₁/a with Z= 4, (7), and 2, (8), in a unit cell of dimensions a= 32.569(9), b= 8.535(4), c= 9.482(5)Å, and β= 93.33(3)°.