Study of novel η 5-cyclopentadienyl and η 6-arene platinum group metal complexes containing a N 4-type ligand and their structural characterization

Abstract

The mononuclear η 5-cyclopentadienyl complexes [(η 5-C 5H 5)Ru(PPh 3) 2Cl], [(η 5-C 5H 5)Os(PPh 3) 2Br] and pentamethylcyclopentadienyl complex [(η 5-C 5Me 5)Ru(PPh 3) 2Cl] react in the presence of 1 eq. of the tetradentate N, N′-chelating ligand 3,5-bis(2-pyridyl)pyrazole (bpp-H) and 1 eq. of NH 4PF 6 in methanol to afford the mononuclear complexes [(η 5-C 5H 5)Ru(PPh 3)(bpp-H)]PF 6 ([ 1]PF 6), [(η 5-C 5H 5)Os(PPh 3)(bpp-H)]PF 6 ([ 2]PF 6) and [(η 5-C 5Me 5)Ru(PPh 3)(bpp-H)]PF 6 ([ 3]PF 6), respectively. The dinuclear η 5-pentamethylcyclopentadienyl complexes [(η 5-C 5Me 5)Rh(μ-Cl)Cl] 2 and [(η 5-C 5Me 5)Ir(μ-Cl)Cl] 2 as well as the dinuclear η 6-arene ruthenium complexes [(η 6-C 6H 6)Ru(μ-Cl)Cl] 2 and [(η 6- p- iPrC 6H 4Me)Ru(μ-Cl)Cl] 2 react with 2 eq. of bpp-H in the presence of NH 4PF 6 or NH 4BF 4 to afford the corresponding mononuclear complexes [(η 5-C 5Me 5)Rh(bpp-H)Cl]PF 6 ([ 4]PF 6), [(η 5-C 5Me 5)Ir(bpp-H)Cl]PF 6 ([ 5]PF 6), [(η 6-C 6H 6)Ru(bpp-H)Cl]BF 4 ([ 6]BF 4) and [(η 6- p- iPrC 6H 4Me)Ru(bpp-H)Cl]BF 4 ([ 7]BF 4). However, in the presence of 1 eq. of bpp-H and NH 4BF 4 the reaction with the same η 6-arene ruthenium complexes affords the dinuclear salts [(η 6-C 6H 6) 2Ru 2(bpp)Cl 2]BF 4 ([ 8]BF 4) and [(η 6- p- iPrC 6H 4Me) 2Ru 2(bpp)Cl 2]BF 4 ([ 9]BF 4), respectively. These compounds have been characterized by IR, NMR and mass spectrometry, as well as by elemental analysis. The molecular structures of [ 1]PF 6, [ 5]PF 6 and [ 8]BF 4 have been established by single crystal X-ray diffraction studies and some representative complexes have been studied by UV–vis spectroscopy.