Luminescence quenching of *[Ru(bpy)3]2+ by ruthenium(II) tetraphosphite complexes with different phosphite ligands

The luminescence quenching of excited Tris(2,2-bipyridine)ruthenium(II) ions by trans-[RuCl2{P(OR)3}4] complexes with different alkyl chain ligands (R=C2H5, C2H5Cl, nC4H9, iC3H7 o-tolyl and tC4H9) was investigated. None of the acceptor Ru(II) phosphite complexes were luminescent, and the rate constants of the bimolecular system were determined within the range of 1.15 and 0.28×108 M−1 s−1 for R=C2H5 and tC4H9, respectively. The results indicate a direct effect of the alkyl chains in the rate constants, showing a decrease of kq as a function of increased of the alkyl chains (R) in the ruthenium(II) tetraphosphite complexes. The greater the R group content in the phosphite ligand, the more difficult the electron transfer is.