Thermally and photochemically induced co-ordination change in ruthenium(II) bis(2,2′-bipyridine) complexes containing pyridyltriazole ligands

A series of Ru^II(bipy)₂ complexes (bipy = 2,2′-bipyridine) containing monodentate co-ordinated pyridyltriazole ligands has been prepared and characterised. The species are obtained by either thermal or photochemical methods. The co-ordination mode of the products obtained has been investigated using spectroscopic techniques. The molecular structure of one of the products, bis(2,2′-bipyridine)chloro-[3-methyl-1-(pyridin-2-yl)-1,2,4-triazole] ruthenium(II) hexafluorophosphate, has been determined. The compound crystallises in the triclinic space group P1 with unit-cell parameters a = 8.599(12), b = 13.503(16), c = 16.526(16) Å, α = 89.88(9), β = 117.22(8), γ = 111.08(10)° and Z = 2. The pyridyltriazole is co-ordinated via the N⁴ nitrogen atom. In the compounds containing monodentate 4-methyl-3-(pyridin-2-yl)-1,2,4-triazole the ligand is most likely co-ordinated via the N¹ atom. The conversion of the photoproduct acetonitrilebis(2,2′-bipyridine)[4-methyl-3-(pyridin-2-yl)-1,2,4-triazole] ruthenium(II) into the parent complex containing the chelating pyridyltriazole ligand by thermal as well as photochemical methods is reported.