PREPARATION PROPERTIES OF ME-CYCLOPENTANE AND DINEOPENTYL DERIVATIVES OF MO- AND W-CENE X-RAY CRYSTAL STRUCTURE OF BIS(CYCLOPENTADIENYL)MOCYCLOPENTANE

The interaction of [ M o ( ~ - C ~ H ~w)ith~ tIh~e ]a ppropriate dilithium reagents yields the metallacyclopentane derivatives [ Mo(C H2CH2CH2CH2()q - C5H5)2] (1) , [ Mo(CH2 (CD2) 2CH2)( q-C5 H5)2 1 (2), and [Mo(CH2CHMeCHMeCH2) (q-C5H5)2] (3). Structures for these compounds are proposed on the basis of elemental analysis, n.m.r. and mass spectrometry. The crystal structure of the molybdenum parent compound (1 ) has been determined from X-ray diffractometer data and refined by least squares. Crystals of (1 ) are Monoclinic, space group P2,/c, with unit-cell parameters a = 11.352(2), b = 7.665(1), c = 16.1 11 (3) A, p = 121.37(2)", and Z = 4; R = 0.047 based on 1 272 observed reflections. The structural details are discussed also in terms of their chemical significance. Carbonylation of (1 ) yields cyclopentanone ; compounds (1 )-(3) give, by thermal decomposition, the corresponding olefins as the major products in addition to small amounts of olefins derived from metallacycle fragmentation. The dineopentyl derivatives [M (CH2CMe,),(q-C5H5),] (M = Mo or W) have been prepared and their thermal decomposition has been investigated. NO isolable metallacyclobutane has been obtained.