ELECTRON AND BROMINE TRANSFER-REACTIONS BETWEEN METAL-CARBONYL ANIONSAND METAL-CARBONYL BROMIDES - CRYSTAL AND MOLECULAR-STRUCTURE OF DIMERIC INDENYL MOLYBDENUM TRICARBONYL

Reactions of metal carbonyl anions with metal carbonyl halides proceed by two separate paths. When the reactant anion is a strong nucleophil e, the halogen is transferred, resulting in a new metal carbonyl halid e and a new metal carbonyl anion as intermediates. The ultimate produc ts, in this case, are the homobimetallic complexes. In cases where the reactant metal carbonyl anion is a poor nucleophile, a single electro n transfer occurs, leading to the two homobimetallic complexes and to the heterobimetallic complex. Halide effects and possible indenyl effe cts are examined. The complex [Mo(indenyl)(CO)3]2 Crystallizes in the noncentrosymmetric orthorhombic space group P2(1)2(1)2(1) (No. 19) wit h a = 7.3572(7) angstrom, b = 14.4539(12) angstrom, c = 19.983(2) angs trom, V = 2125.0(4) angstrom3, and Z = 4. Diffraction data were collec ted on a Siemens R3m/V diffractometer for 2theta = 5-45-degrees (Mo Ka lpha), and the structure was solved and refined to R = 3.21 % and R(w) = 3.23 % for all 2786 independent reflections (R = 2.26 % and R(w) = 2.81 % for those 2314 reflections with \F(o)\ > 6sigma(\F(o)\). The co mplex is held together by a Mo-Mo single bond (Mo(1)-Mo(2) = 3.251(1) angstrom), and has Mo-CO distances ranging from 1.956(6) to 1.988(7) a ngstrom, averaging 1.970 +/- 0.016 angstrom. Molybdenum-carbon distanc es to the eta5-indenyl rings range from 2.300(7) to 2.427(6) angstrom for Mo(1) and 2.306(7) to 2.430(6) angstrom for Mo(2).