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The synthesis and isolation of new RuII–acetonitrile complexes, of general formula trans,fac-[Ru(bpea)(B)(MeCN)](BF4)2(bpea = N,N-bis(2-pyridylmethyl)ethylamine; B = bpy, 2,2′-bipyridine, 4; B = dppe, 1,2-bis(diphenylphosphino)ethane, 5), together with a synthetic intermediate trans,fac-[Ru(NO3)(bpea)(dppe)](BF4), 6, are described. Ru(bpea)Cl3, 1, is used as the starting material for the synthesis of all complexes 2–6 presented in this paper, which are characterized by analytical, spectroscopic (IR, UV/Vis, 1D and 2D NMR), and electrochemical techniques (cyclic voltammetry). Furthermore, complexes 4, 5, and 6 have also been characterized in the solid state by single crystal X-ray diffraction analysis. Their structures show a distorted octahedral geometry where the bpea ligand binds in a facial mode, the bidentate ligands bpy and dppe bind in a chelate manner, and finally the MeCN or the NO3-ligand occupy the sixth position of the octahedral Ru metal centre. The kinetics of the basic hydrolysis of the coordinated MeCN ligand for complexes 4 and 5 and for the related complex [Ru(phen)(MeCN)([9]aneS3)](BF4)2, 7, which contains the 1,4,7-trithiacyclonane ligand ([9]aneS3) and 1,10-phenanthroline (phen) is also described. Second-order rate constants for acetonitrile hydrolysis measured at 25°C of k= 1.01 × 10-3M-1s-1for 4, 1.08 × 10-4M-1s-1for 5, and 6.8 × 10-3M-1s-1for 7, have been obtained through UV-vis spectroscopy. Activation parameters have also been determined over the temperature range 25.0–45.0°C and agree with a mechanism that involves an associative rate-determining step. Finally the electronic and steric influence of the auxiliary ligands on this reaction for the above and related complexes is discussed. [ABSTRACT FROM AUTHOR]

Three novel asymmetric ruthenium(ii) complexes, [Ru(bpy)2(PAIDH)]2+1, [Ru(phen)2(PAIDH)]2+2, and [Ru(dmp)2(PAIDH)]2+3 (bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline, dmp = 2,9-dimethyl-1,10-phenanthroline, PAIDH = 2-pyridyl-1H-anthra[1,2-d]imidazole-6,11-dione), have been synthesized and characterized. The structure of the deprotonated complex [Ru(dmp)2(PAID)]+4 has been determined by single-crystal X-ray diffraction techniques, and the anthraquinone moiety is approximately coplanar with the imidazole ring. The DNA binding properities of complexes 1, 2, and 3 to calf-thymus DNA (CT-DNA) were investigated. Spectroscopic studies and viscosity experiments suggest that the RuIIcomplexes intercalate into DNA base pairs by the extended anthraquinone unit, and the ancillary ligands have significant effects on the spectroscopic properties and DNA binding behaviour of the RuIIcomplexes. [ABSTRACT FROM AUTHOR]