Syntheses and structures of metal-metal triply bonded M2R6 compounds: consideration of starting materials, stability, and structural parameters

The syntheses and structures of four homoleptic metal-metal triply-bonded M 2R6 compounds [Mo-2(CH2CMe2Ph)(6), 1; Mo-2(CH2SiMe2Ph)(6), 2; W-2(CH2SiMe2P h)(6), 3; and W-2(CH2Ph)(6), 4] are reported. The synthetic effort suggests that ditungsten compounds are inherently more difficult to prepare and mor e thermally sensitive than dimolybdenum compounds, probably as a result of the larger dimetal core the ligands must protect. The structural data confi rm that dimetal hexaalkyls exhibit shorter M=M distances than do,dimetal he xaalkoxides, even in a matched pair case where steric differences are minim al. (C) 1999 Elsevier Science Ltd. All rights reserved.