253157-39-0Relevant academic research and scientific papers
Chemistry of azopyrimidines. Part II. Synthesis, spectra, electrochemistry and X-ray crystal structures of isomeric dichloro bis[2-(arylazo)pyrimidine] complexes of ruthenium(II)
Santra, Prasanta K.,Misra, Tarun K.,Das, Debasis,Sinha, Chittaranjan,Slawin, Alexandra M.Z.,Woollins, J. Derek
, p. 2869 - 2878 (1999)
2-(Arylazo)pyrimidines (aapm, 3) are new N,N′- chelating ligands in the azoimine family and were reacted with RuCl3 in ethanol under refluxing conditions. Three isomers of the composition Ru(aapm)2Cl2 have been chromatographically separated and are established as having trans-cis-cis (tcc), cis-trans-cis (ctc) and cis-cis-cis (ccc) configurations with reference to the order of coordination pairs as Cl; N(pyrimidine), N and N(azo), N′. Two of the three isomeric structures have been confirmed by X-ray crystallography. In both of these structures, the Ru-N(azo) distances are relatively shorter than those of Ru-N(pyrimidine), indicating stronger bonding in the former and the presence of a Ru-(aapm) π-interaction that is localised in the Ru-azo fragment. The isomer configuration is supported by IR and 1H NMR data. The complexes exhibit t2(Ru)→π*(aapm) MLCT transitions in the visible region. Redox studies show the Ru(III)/Ru(II) couple in the green complexes [tcc-Ru(aapm)2Cl2] at 1.1-1.2 V and in the blue complexes [ctc- and ccc-Ru(aapm)2Cl2] at 1.2-1.4 V versus saturated calomel electrode (SCE) and two successive azo reductions. The difference in the first metal and ligand redox potentials is linearly correlated with νCT [t2(Ru)→π*(aapm)]. Elsevier Science Ltd.
