Inorg. Chem. 2003, 42, 5219−5230
Binuclear Homoleptic Manganese Carbonyls: Mn2(CO)x (x ) 10, 9, 8, 7) Yaoming Xie,† Jee Hwan Jang,‡ R. Bruce King,† and Henry F. Schaefer, III*,† Center for Computational Quantum Chemistry and Department of Chemistry, UniVersity of Georgia, Athens, Georgia 30602, and Computational Science Engineering Center, Samsung AdVanced Institute of Technology, P.O. Box 111, Suwan 440-600, Korea Received April 3, 2003
The unsaturated homoleptic manganese carbonyls Mn2(CO)n (n ) 7, 8, 9) are characterized by their equilibrium geometries, thermochemistry, and vibrational frequencies using methods from density functional theory (DFT). The computed metal−metal distances for global minima range from 3.01 Å for the unbridged Mn2(CO)10 with a Mn−Mn single bond to 2.14 Å for a monobridged Mn2(CO)7 formulated with a metal−metal quadruple bond. The global minimum for Mn2(CO)9 has a four-electron bridging µ-η2-CO group and a 2.96 Å Mn−Mn distance suggestive of the single bond required for 18-electron configurations for both metal atoms. This structure is closely related to an experimentally realized structure for the isolated and structurally characterized stable phosphine complex [R2PCH2PR2]2Mn2(CO)4(µ-η2-CO). An unbridged (OC)4Mn−Mn(CO)5 structure for Mn2(CO)9 has only slightly (
