90742-45-3Relevant academic research and scientific papers
Ruthenium complexes with diazabutadienes. 3. Trans and cis isomers of dichlorobis(diazabutadiene)ruthenium, (RN=CR′-CR′=NR)2RuCl2
Dieck, Heindirk Tom,Kollvitz, Wolfgang,Kleinw?chter, Ingo
, p. 2685 - 2691 (2008/10/08)
The preparation of a series of (diazabutadiene)ruthenium complexes, (dad)2RuCl2 (dad = RN=CR′-CR′-NR (R′ = H, CH3; R = C6H5, substituted phenyl group)), is described. In a thermal reaction starting from tetrakis(benzonitrile)dichlororuthenium, blue or green trans-(dad)2RuCl2 are formed first, which isomerize above 130°C to the violet cis complexes. Electron spectroscopic, 1H NMR, and electrochemical data are discussed with respect to symmetry and conformation of the complexes formed. Cis complexes with ligands derived from biacetyl (R′ = CH3) show unusual chemical shifts for aromatic ortho protons, indicating a rigid N-phenyl conformation. Two rotational barriers for symmetry-independent aromatic substituents are detected. While the Ru(II)-Ru(III) redox process is fully reversible for both stereochemistries, the reduction is irreversible. The trans → cis isomerization can be achieved catalytically by electron transfer. The otherwise very inert chloro ligands can easily be substituted at potentials below the irreversible reduction step to give, for example, in the presence of free dad and after reoxidation complexes [Ru(dad)3]2+.
