Substituted metal carbonyls XV. Crystal and molecular structures of two isomorphous singly diphosphine-bridged complexes (OC)5M(μ-dppf)M(CO)5·CH2Cl2 (M = Cr, Mo; dppf = (Ph2PC5H4)2Fe)

Abstract

The crystal structures of two dinuclear compounds (OC)5M(μ-dppf)M(CO)5·CH2Cl2 (M = Cr, Mo; dppf = (Ph2PC5H4)2Fe), determined by single-crystal X-ray diffraction studies, were found to be isomorphous. (Crystal data: (OC)5Cr(μ-dppf)Cr(CO)5, space group C2/c, a 16.659(3), b 15.350(5), c 18.877(2) Å, β 112.43(2)°, Final R 0.046 for 2999 observations. (OC)5Mo(μ-dppf)Mo(CO)5, space group C2/c, a 16.705(4), b 15.545(4), c 19.091(3) Å, β 111.92(2)°, Final R 0.037 for 3332 observations). The diphosphine serves as a single bridge between two essentially unperturbed metal carbonyl spheres. The iron was located on a two-fold axis as required crystallographically. The relationship between the phosphinoferrocenyl geometry and the stability of this type of "open" complexes is described together with the solid-state decomposition data from Thermogravimetric (TG) and Differential Scanning Calorimetric (DSC) analyses. © 1990.