Zweikernige Mangan- und Rheniumkomplexe mit gemischt aliphatischen-aromatischen Kohlenwasserstoffbrücken / Dinuclear Manganese and Rhenium Complexes with Mixed Aliphatic-Aromatic Hydrocarbon Bridges

Abstract

The symmetrically hydrocarbon-bridged complexes (OC)5M-(CH2)n+1-X-(CH2)n+l-M(CO)5 [n = 1, X = 1,4-C6H4, M = Mn (2a), M = Re (3a); n = 2, X = 1,4-C6H4, M = Mn (2b), M = Re (3b); n = 1, X = 1,3-C6H4, M = Mn (5a), M = Re (6a); n = 2, X = 1,3-C6H4, M = Mn (5b), M = Re (6b); n = 1, X = 1,2-C6H4, M = Mn (8a), M = Re (9a); n = 2, X = 1,2-C6H4, M = Mn (8b), M = Re (9b)] are obtained by the reaction of the bistriflates X[(CH2)„-CH2-OSO2CF3]2 [X = 1,4-C6H4, n = 1 (la), n = 2 (lb); X = 1,3-C6H4, n = 1 (4a), n = 2 (4b); X = 1,2-C6H4, n = 1 (7a), n = 2 (7b)] with the carbonyl metalates [M(CO)5]- (M = Mn, Re) in THF and dimethyl ether, respectively. According to an X-ray structural analysis 8a crystallizes in the triclinic space group P1̅ with Ζ = 2. Depending on the solvent, the reaction of 7 a with [Mn(CO)5]~ affords also the cyclic carbene complex 10a. The behavior of the manganese compounds toward CO has been investigated exemplarily in the case of 8a and leads to the diacyl complex 1,2-C6H4[CH2CH2C(O)Mn(CO)5]2 (11). Upon reaction with Na2CO3/CH3OH 11 is converted to give the corresponding diester 1,2-C6H4[CH2CH2C(O)OCH3]2 (12).

Fluoroalkyl Radical Generation by Homolytic Bond Dissociation in Pentacarbonylmanganese Derivatives

“…In the ordered structure of complex 5 , which has three α‐F substituents, the Mn−CF 3 distance (2.067(3) Å) is ≈0.1 Å shorter than the Mn−CH 2 CF 3 distance in compound 7 (2.162(2) Å). For comparison, other distances to the sp 3 ‐hybridized C atoms without any F substituents are 2.214(3) Å in [(CO) 5 Mn(CH 2 CH=CHCOOPh)] and 2.195(6) and 2.196(8) Å in [(CO) 5 Mn(CH 2 CH 2 ‐ o ‐C 6 H 4 −CH 2 CH 2 )Mn(CO) 5 ], whereas positional disorder in the simpler reference compound [(CO) 5 Mn(CH 3 )] prevented an accurate determination of the Mn−CH 3 distance . The distance in [(CO) 5 Mn(CH 2 Cl)], which has one α‐Cl substituent, is 2.125(10) Å .…”