Synthesis and Characterizations of p ‐Xylyl Bridged Dinuclear Complexes of Molybdenum and Tungsten. The Crystal Structure of μ‐ p ‐xylyl‐bis(1‐Me‐3‐SiMe3‐cyclopentadienyltricarbonylmolybdenum)

The reactions of R 1 R 2 CpM(CO) 3 − Li + (M = Mo, W) with α, α′‐dichloro‐ p ‐xylene yielded p ‐xylyl bridged dinuclear complexes of R 1 R 2 CpM(CO) 3 in high yields. All of such new complexes are very stable to air and water. Some of them are stable even in dilute acids and dilute bases. Complex 4 crystallizes in the monoclinic system, space group P 2 1 /n, with a = 6.847(5) Å, b = 9.838(2) Å, c = 25.140(10) Å, β = 96.56(5)°, Z = 2, R F =0.077, R w = 0.105 and V = 1682.4(14) Å 3 .