Reactions of diiron nonacarbonyl with pyrrolyl-, pyridyl- and thienyl-substituted azines: N-N bond cleavage, cyclometallation and C=N sigma and pi-bonding

摘要

The reactions of 1,4-di-(N-methyl-2'-pyrrolyt)-2,3-diaza-1,3-butadiene (1), 1,4-di-(6-methyl-2-pyridyl)-2,3-diaza-1,3-butadiene (2) and 3,6-di-(2'-thienyt)-1,2,4,5-tetrazine (3) with Fe-2(CO)(9) in toluene, THF and benzene, respectively, yielded various types of hexacarbonyldiiron complexes with five different coordination modes: (1) a complex with two 2-pyrrolylmethylideneamido bridging ligands, 1a, which resulted from N-N bond cleavage of ligand 1, (2) a cyclometallated (mu-2,3-eta(1):eta(2)-pyrrolyl; eta(1):eta(1)(N)) complex 1b and a cyclometallated (mu-2,3-eta(1):eta(2)-thienyl; eta(1):eta(1)(N)) complex 3b, (3) a diaza-bridged complex 3a, (4) an imine-bridged (mu-sigma;pi-eta(1):eta(2)-(C,N); eta(1)(N-py)) complex 2a and (5) an imine-bridged (mu-pi-eta(1):eta(1)-(C, N); eta(1) (N-py); eta(1)(N'(py))) complex 2b. The molecular structures of the ligands 1 and 3 as well as of the complexes 1a, 2a and 3a have been determined by single-crystal X-ray crystallography. (C) 2006 Elsevier Ltd. All rights reserved.