Derivatographic Studies on Transition Metal Complexes. X. Thermal Octahedral-to-Square Planar Transformation of Ni(<i>NN</i>-deen)2X2·<i>n</i>H2O in Solid Phase

Abstract

Abstract Thermal reactions of the complexes [Ni(H2O)2(NN-deen)2]X2·nH2O (NN-deen is N,N-diethylethylene-diamine and X is Cl or Br) were investigated. It was found by derivatography and spectral and magnetic measurements that the bromide undergoes transformation from octahedral to square planar structure by “deaquation” upon heating, whereas the chloride turned to the dichloro complex by thermal “deaquation-anation” losing the coordinated water and drawing chloride ion into the coordination sphere with retention of octahedral structure around the central metal. No such transformation could be found in the corresponding iodide and nitrate, since only diamagnetic complexes, [Ni(NN-deen)2]X2 (X is I or NO3), and no paramagentic complexes were obtained.