PI-ARENE COMPLEXES .7. HETEROBIMETALLIC COMPLEXES OF CHROMIUM AND MANGANESE WITH BRIDGING SIGMA,PI-BENZENE AND SIGMA,PI-BENZOYL LIGANDS
Lotz, S; Schindehutte, M; Vanrooyen, PH
The complexes [Cr{η6-C6H4XLi}(CO)3] (X = H (a), F (b)) react with [Mn(CO)5Br] to produce novel heterobimetallic compounds with bridging. Ï,Ï-benzoyl ligands, (η6-{(CO)5Mn}C(O)C6H5X)Cr(CO)3 (1). When the reaction was executed in the presence of P(OMe)3, complexes with a bridging benzoyl, (η6-{(CO)4(P-(OMe)3)Mn}C(O)C6H5)Cr(CO)3 (1c (higher yield)), as well as a bridging phenyl ligand, (η6-{(CO)4(P-(OMe)3)Mn}C6H5)Cr(CO)3 (3c), were obtained. By the refluxing of 1c in hexane, it was converted quantitatively into 3c. Using PPh3 instead, the only product from the reaction was the unique complex (η6-{(CO)4(PPh3)Mn}C6H4X)Cr(CO)3 (3a,b). Bridging benzoyl complexes [formula omitted] were obtained with [formula omitted]. The formation of [(η6: η6-XC6H4C(O)C6H4X){Cr(CO)3}2] (2) as a minor byproduct from the reactions which generated benzoyl dimers represents an interesting carbonyl-transfer reaction. Upon isolation of la from a dichloromethane-hexane solution, the complex crystallizes in the orthorhombic space group Pna21 with a = 13.084 (2) Ã
, b = 6.089 (2) Ã
, c = 40.036 (5) Ã
, and Z = 8 with two molecules in the asymmetric unit. The structure of 1a was determined from 5306 unique data (0 ⤠h ⤠18, 0 ⤠k ⤠8, 0 ⤠l ⤠56), and refinement of 469 variables against 3521 observed (>Ï(I)) data yielded Rw = 0.059. Recrystallization of the manganese-phosphorous complex 3a from a dichloromethane-hexane solution yielded crystals that were orthorhombic, Pbca, with a = 17.217 (2) Ã
, b = 16.407 (5) Ã
, c = 20.530 (10) Ã
, and Z = 8. The structure of 3a was determined from 8996 unique data (0 ⤠h ⤠24, 0 ⤠k ⤠22, 0 ⤠l ⤠28), and refinement of 371 variables against 3465 observed (>3Ï(I)) data yielded Rw = 0.035. © 1992, American Chemical Society. All rights reserved.