Thermal Square Planar-to-octahedral Transformation of Nickel(II) Complexes Containing 1,2-Diphenyl-1,2-ethanediamine in the Solid Phase

Abstract

Abstract The following ten nickel(II) complexes with meso- or dl-1,2-diphenyl-1,2-ethanediamine (abbreviated as meso-stien and dl-stien, respectively) were prepared, and their thermal behavior was investigated in the solid phase: [Ni(meso-stien)2]X2 (X=Cl, Br, I, NO3, or ClO4), [Ni(dl-stien)2]X2 (X=I or ClO4), and [Ni(H2O)2(dl-stien)2]X2 (X=Cl, Br, or NO3). The square planar bis(dl-stien) complex chloride, bromide, and nitrate obtained by thermal dehydration of their respective octahedral diaqua complexes were found by various techniques to be transformed, upon further heating, to the octahedral diacido bis(dl-stien) complexes. The complexes containing dl-stien have a stronger tendency to show such structural transformations than those containing meso-stien. The reason for this difference is discussed.