Studies on ruthenium(II) macrocyclic amine complexes. Synthesis and X-ray structure of the (R,S,R,R) isomer of trans-[RuII(L)(N3)(NCMe)]PF6(L = 1,4,8,11-tetramethyl-1,4,8,11-tetra-azacyclotetradecane)

Abstract

The reaction between K₂[RuCl₅(NO)] and L (L = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane) in ethanol at reflux gave an intermediate product which, on treatment with N₂H₄·H₂O in acetonitrile yielded trans-[Ru^II(L)(N₃)(NCMe)]PF₆. This azide complex crystallizes in space group P2₁/n, with a= 14.775(3), b= 18.083(2), c= 18.167(2)Å, β= 90.26(1)°, and Z= 8. One of the two independent cations has a disordered ligand L, and the methyl groups in L of the ordered cation adopt a ‘three-up, one-down’(R,S,R,R) configuration. The measured Ru–N(acetonitrile) bond lengths, 1.976(7) and 2.003(7)Å, are significantly shorter than the corresponding distance of 2.149(6)Å in the (R,S,R,R) isomer of trans-[Ru(L)O(NCMe)][PF₆]₂, attesting to a greater trans influence of the oxo ligand as compared to the azide ligand.