THE FIRST STRUCTURALLY CHARACTERIZED TRINICKEL CLUSTER WITH AN OPEN STRUCTURE - CRYSTAL AND MOLECULAR-STRUCTURE OF HC=C(PH)-C(PH)=CPH]NI(MU-ETA(2)ETA(2)-PHC-CPH)NICP

Reaction of nickelocene with methyllithium in the presence of diphenyl acetylene at the molar ratio of reactants 1:1:2 produces a trinickel c luster with an open structure. The cluster contains a bent arrangement of nickel atoms. Two of the alkyne units are linked via a carbon-carb on bond to produce a nickelacyclopentadienyl ring, while the third alk yne unit remains independently coordinated to the cluster via two pi-b onds, Two Cp groups are bonded to two terminal nickel atoms. The clust er crystallizes from methylene chloride with solvent molecules in a mo noclinic crystal system and P2(1)/n space group. Corresponding unit ce ll parameters were determined as: a = 12.4385(13) Angstrom; b = 24.994 (3) Angstrom; c = 13.9657(14) Angstrom; beta = 91.457(8)degrees; V = 4 340.4(8) Angstrom(3); Z = 4. (C) 1998 Elsevier Science S.A. All rights reserved.