Einkernige Carbonylmetall-Komplexe des Eisens und Rutheniums, M(CO) n[P(C 7H 7) 3] (M=Fe, Ru; n=4,3,2), mit dem mehrzähnigen Liganden Tri(1-cyclohepta-2,4,6-trienyl)phosphan

Abstract

A series of trigonal-bipyramidal complexes of the type M(CO) n [P(C 7H 7) 3] (M=Fe, Ru; n=4,3,2) has been investigated in which the phosphorus atom of the ligand tri(1-cyclohepta-2,4,6-trienyl)phosphane, P(C 7H 7) 3 ( 1), is coordinated in an axial position and up to two olefinic side-arms may be used for additional coordination to the metal in equatorial positions. The reaction of either Fe 2(CO) 9 or Fe 3(CO) 12 with 1 in THF solution leads to the phosphane complex Fe(CO) 4[P(C 7H 7) 3] ( 4a); the ruthenium analogue 4b is obtained from Ru 3(CO) 12 under irradiation. Stepwise photo-elimination of two equatorial CO ligands can be used to convert 4a, b through the intermediate M(CO) 3[P(C 7H 7) 2( η 2-C 7H 7)] (M=Fe ( 5a), Ru ( 5b)) into M(CO) 2[P(C 7H 7)( η 2-C 7H 7) 2] (M=Fe ( 6a), Ru ( 6b)). In C 6D 6 solution, the bis(olefinic) complexes 6a, b slowly isomerize to give the orange end-products M(CO) 2[P(C 7H 7) 2( η 4-C 7H 7)] ( 7a, b) in which only one of the three seven-membered rings is coordinated to the metal in the form of a norcaradienyl substituent. The new complexes were characterized by a consistent set of 1H-, 13C- and 31P-NMR spectra, and the molecular geometry of 6a has been determined by a single-crystal structure analysis.