The ditopic ligands 4′-(diphenylphosphino)-2,2′:6′,2 ″-terpyridine L1 and 4′-(oxodiphenylphosphanyl)-2,2′:6′,2 ″-terpyridine L2: co-ordination to iron(II), ruthenium(II), cobalt(II) and palladium(II); crystal structures of [RuL22][PF6]2·H 2O·MeCN and trans-[PdCl2L12]· 2.5CH2Cl2

Abstract

The new compound 4′-(diphenylphosphino)-2,2′:6′,2 ″-terpyridine L ¹ has been prepared; in solution it readily oxidises to the corresponding phosphine oxide, L ² . The reaction between L ¹ and FeCl ₂ ·4H ₂ O yielded salts containing [FeL ¹ ₂ ] ²⁺ , however, oxidation resulted in the formation of [FeL ² ₂ ] ²⁺ . The corresponding ruthenium(II) complex of L ² has also been prepared and structurally characterised as the hexafluorophosphate salt; attempts to prepare [RuL ¹ ₂ ] ²⁺ always resulted in oxidation of the ligand to L ² . The reaction of L ¹ with cobalt(II) acetate gave [CoL ¹ ₂ ] ²⁺ which has been isolated as the hexafluorophosphate salt. The complexes have been characterised by IR and NMR spectroscopies, mass spectrometry and elemental analysis. Compound L ¹ also reacts with [PdCl ₂ (NCMe) ₂ ] to give trans-[PdCl ₂ L ¹ ₂ ] which has been fully characterised; results of an X-ray diffraction study confirm the trans configuration of the complex.