Synthesis and characterisation of a series of ruthenium scorpionate complexes with B-H … M agostic interactions. Crystal structure of [RuH(#kappa#~2-N,BH Tp~(Tn)(PMe_3)(cod)] (Tp~(Tn) =hydrotris[3-(2-thienyl)pyrazol-1-yl]borate)

摘要

A series of monohydrides of Ru~(II) of formula RuH(Tp~R) (cod) 1-3 have been synthesized from the reaction of [RuH(NH_2Nme_2)_3(cod)]BPh_4 with the corresponding Tp~R ligand {hydrotris(7-methylindazol-2-yl)borate, Tp~(Bo,7Me), 1; hydrotris[3-(2-thienyl)pyrazol-1-yl]borate, Tp~(Tn), 2' tris[3-(2,4-dimethoxyphenyl)pyrazol-1-yl]hydroborate, Tp~(2,4(Ome)_2Ph), 3}. In these compounds the Tp ligand is #kappa#~3 N,N', BH coordinated with a B-H …Ru agostic interaction. Reactions of 1 and 2 with two-electron donor ligands, L = Pme_3, Pme_2Ph and CN-t-Bu, led to the formation of complexes of formula RuH(Tp~R)(L)(cod) (Tp~R = Tp~(Bo,7Me), L = Pme_2Ph5 or CN-t-Bu 6; Tp~R = Tp~(Tn), L = Pme_3 7, Pme_2Ph 8 or CN-t-Bu 9). In this new series the incoming ligands repalce one of the coordinated pyrazole rings instead of the stated B-H…Ru interaction which remains and consequently the Tp~R ligands are K~2 N,BH coordinated. The molecular structure of 7 was determined by an X-ray diffraction study. The ruthenium atom has a distorted octahedral environment with the ligand Tp~(Tn) coordinated through only one pyrazole ring and an agostic B-H group. The two hyrides are in a mutually trans disposition with an angle of 166 deg . The Ru …H distance is 2.07 (5) and Ru-H_(terminal) 1.33(5) A. The molecular structure of the model complex [RuH(#kappa#~2-N,BH-Tp)(PH_3)(H_2C = CH_2)_2] has been optimised with the aid of ab initio calculations in order to compare the structural with those of the experimentally determined structure.