Thermally induced phase transition and X-ray crystal structure of bis(N,N′-dimethyl-1,2-ethanediamine)di-isothiocyanatonickel(II)

摘要: The complex [Ni(MeNHCH2CH2NHMe)2(NCS)2](1) has been synthesised and characterised by X-ray crystallography. It undergoes an irreversible endothermic phase transition (452.5–468.5 K, ΔH= 13.4 kJ mol–1) to species (2) which reverts (1) in a humid atmosphere. Complex crystallises the monoclinic space group C2/c with a= 13.069(2), b= 9.783(3), c= 15.074(4)A, β= 111.40(2)°, Z= 4. structure solved Patterson successive Fourier methods refined R= 0.032 for 1 240 independent observed reflections. co-ordination around nickel atom, lying on crystallographic inversion centre, is close octahedral two thiocyanate N atoms trans position. chelate rings exist δλ conformation. For (2), a=b= 8.16(3), 7.53(2)A, α=β= 107.0(2), γ= 73.6(3)°, 1. Crystallographic i.r. spectroscopic data suggest non-centrosymmetric qualitative change conformation of δδ or λλ.