Synthesis and structural studies of copper(II) and nickel(II) complexes containing 4,5-diazafluoren-9-one and pseudohalides: Metal ion directed isomer preference

Abstract

Three new hexacoordinated compounds, trans-[Cu(dafone)2(NCS) 2] (1), trans-[Cu(dafone)2(NCO)2]⋯MeCN (2) and cis-[Ni(dafone)2(NCS)2] (3) (dafone = 4,5-diazafluoren-9-one) have been prepared and X-ray crystallographically characterized. Structural study reveals that in these complexes each metal centre adopts a distorted octahedral geometry with an MN6 choromophore coordinated by four N atoms of chelated dafone ligands and two N atoms of terminal pseudohalides. The effect of dafone with a long chelate bite to adapt to the electronic preferences of the metal ions by varying the bite distance within certain limits is described. In the crystalline states, different kinds of non-covalent interactions promote dimensionalities in the studied complexes.