Molybdenum and Tungsten Cyclopentadienone Complexes. 1. Synthesis and Characterization

Abstract

The labile complexes M(CO)3(CH3CN)3 (M = Mo, W) undergo facile oxidative addition reactions with 4-bromo-2-cyclopentenone to give M(η3-C5H5O)(CO)2(CH3CN)2Br 1a and 2. Complex 1a crystallizes in space group P21/m (No. 11) with a = 8.631 (2) A, b = 12.852 (3) A, c = 6.659 (2) A, β = 109.27 (1)°, V = 697.3 (3) A3, and Z = 2. The structure was refined to R(F) = 0.023 (F ≥ 4σF). 1 and 2 react with potassium tris(pyrazolyl)borate (K[HBpz3]), 2,2‘-bipyridyl (bipy), and bis(diphenylphosphino)methane (dppm) to give neutral η3-cyclopentenoyl complexes of types M(η3-C5H5O)(CO)2(HBpz3) 3a and 4, M(η3-C5H5O)(CO)2(bipy)Br 5 and 6, and M(η3-C5H5O)(CO)2(dppm)Br 7 and 8, respectively, in high yields. Single crystal structural studies have been carried out for complexes 3a, 4, and 8. 3a crystallizes in space group Pbca (No. 61) with a = 19.819 (3) A, b = 13.899 (3) A, c = 13.088 (2) A, V = 3605 (1) A3, and Z = 8, and the structure was refined to R(F) = 0.026 (F ≥ 4σF). 4 is isostructural with 3a and crystallizes in space g...