Molecular orbital calculations on transition metal complexes : XX. The π-cyclopentadienyl-π-benzene complexes of chromium and manganese

• Published in: Journal of organometallic chemistry Vol. 157; no. 4; pp. 421 - 429
• Main Authors: Clack, Denis W., Warren, Keith D.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 19.09.1978
• ISSN: 0022-328X; 1872-8561
• DOI: 10.1016/S0022-328X(00)94024-5

INDO SCF MO calculations are reported for the complexes (C 5H 5)M(C 6H 6) (M = Cr and Mn) and for the corresponding cations. A 2 A 1 ground state is correctly predicted for the neutral Cr system, and other experimental quantities are satisfactorily reproduced. The dominantly metal d-levels yield the H core sequence e 2 < a 1 < e 1 and the principal interactions were found to be those between the metal e 1 level and the π-orbitals of the C 5H 5 ligand, and between the metal e 2 level and the ligand C 6H 6 π-orbitals. From the state energies of the formally 3 d 5 species estimates were made of the one-electron 3 d splittings in the ligand field model, and comparisons made with similar results for M(C 5H 5) 2, M(C 6H 6) 2, and (C 5H 5)M(C 7H 7) systems: these indicated the general validity of the bonding scheme in which the extent of the metal—ligand interaction via the e 1 and e 2 3 d levels varied systematically with the sizes of the ligand rings.