Mixed-valency with cyanides as terminal ligands: Diruthenium(III,II) complexes with the 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine bridge and variable co-ligands (CN- vs. bpy or NH3)

0341711 - ÚFCH JH 2011 RIV NL eng J - Journal Article
Vergara, M. M. - García Posse, M. E. - Fagalde, F. - Katz, N. E. - Fiedler, Jan - Sarkar, B. - Sieger, M. - Kaim, W.
Mixed-valency with cyanides as terminal ligands: Diruthenium(III,II) complexes with the 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine bridge and variable co-ligands (CN- vs. bpy or NH3).
Inorganica chimica acta. Roč. 363, č. 1 (2010), s. 163-167. ISSN 0020-1693. E-ISSN 1873-3255
R&D Projects: GA MŠMT OC 140; GA MŠMT OC09043
Institutional research plan: CEZ:AV0Z40400503
Keywords : cyano ligands * mixed-valency * Ruthenium complexes
Subject RIV: CG - Electrochemistry
Impact factor: 1.899, year: 2010

New diruthenium complexes (PPN)(4)[(NC)(4)Ru(mu-bptz)Ru(CN)(4)], (PPN)(4) 1, and [(bpy)(2)Ru(mu-bptz)Ru(CN)(4)], 2, (PPN+ = bis(triphenylphospine)iminium; bptz = 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine; bpy = 2,2'-bipyridine), were synthesised and characterised by spectroscopic and electrochemical techniques. The comproportionation constant K-c = 10(7.0) of the mixed-valent species [(NC)(4)Ru(mu-bptz)Ru(CN)(4)](3) as obtained by oxidation of 1(4) in CH3CN is much lower than the K-c = 10(15.0) previously detected for [(H3N)(4)Ru(bptz)-Ru(NH3)(4)](5+), reflecting the competition between CN and bptz for the p-electron density of the metals. Comparison with several other bptz-bridged diruthenium(II, III)complexes reveals an approximate correlation between K-c and the diminishing effective pi acceptor capacity of the ancillary terminal ligands.
Permanent Link: http://hdl.handle.net/11104/0184609