Reactions of the cationic complex [( η6-C 6Me 6) 2Ru 2( μ2-H) 3] + with nitrogen-containing heterocycles in aqueous solution

Abstract

The dinuclear cation [( η 6-C 6Me 6) 2Ru 2( μ 2-H) 3] +( 1) reacts in aqueous solution with pyrazole and 4-methylpyrazole to give the bispyrazolato complexes [( η 6-C 6Me 6) 2Ru 2( μ 2-H)( μ 2- η 1, η 1-N 2C 3H 2R) 2] + (R=H: 2, R=Me: 3). The reaction with 1,2,4-triazole results in the formation of the bistriazolato complex [( η 6-C 6Me 6) 2Ru 2( μ 2-H)( μ 2- η 1, η 1-N 3C 2H 2) 2] +( 4). Successive protonation of the triazolato ligands in 4 leads to the complexes [( η 6-C 6Me 6) 2Ru 2( μ 2-H)( μ 2- η 1, η 1-N 3C 2H 2)( μ 2- η 1, η 1-N 3C 2H 3)] 2+( 5) and [( η 6-C 6Me 6) 2Ru 2( μ 2-H)( μ 2- η 1, η 1-N 3C 2H 3) 2] 3+( 6). The reaction of 1 with 1,2,3-triazole gives a 1:1 mixture of the bistriazolato complexes [( η 6-C 6Me 6) 2Ru 2( μ 2-H)( μ 2- η 1, η 1-N 3C 2H 2) 2] +with parallel ( 7a) and anti-parallel ( 7b) coordination of the triazolato ligands. The single-crystal X-ray structure analyses of 2 (hexafluorophosphate salt) and 4 (tosylate salt) reveal for both complex types a ruthenium–ruthenium backbone being bridged by the two heterocyclic ligands with the N–N axis coordinated in a μ 2- η 1, η 1-fashion. A single-crystal X-ray structure analysis of title complex 1 (hexafluorophosphate salt) confirms the presence of three bridging hydrido ligands with a Ru–Ru distance of only 2.47 Å.