Syntheses, crystal structures and solid state thermochromic conversion of trans-1,2-diaminocyclohexane complexes of copper(II) perchlorate

The complexes CuLn (ClO4)(2) . xH(2)O (L = 1,2-diaminocyclohexane; x = 1, n = 3; x = 0, n = 2) have been synthesized from solution. The complexes [CuL3](ClO4)(2 .) H2O (1, sky blue) and CuL2(ClO4)(2) (2, violet) have been characterized by single crystal structural analyses.n complex ii copper ion possesses distorted octahedral geometry having N-6 chromophore but in complex 2, copper ion possesses distorted (4 + 2) octahedral geometry having N4O2 chromophore. Complex 1, on heating, transforms to 2 accompanied by a sky blue to violet thermochromism, a unique example of a change followed by deaquation-deaminarion-anation reaction in the solid state. (C) 1998 Elsevier Science Ltd. All rights reserved.