CRYSTAL AND MOLECULAR-STRUCTURE AND ELECTRONIC-PROPERTIES OF HEN)(2)(HL)]CENTER-DOT(PHEN)(0.5)CENTER-DOT-7H(2)O (H3L = 1,3,5-TRIAZINE-2,4,6(1H,3H,5H)-TRIONE), A NOVEL N-CYANURATE(2-) DERIVATIVE

The crystal and molecular structure of [Cu(phen)(2)(HL)].(phen)(0.5). 7H(2)O (H3L = 1,3,5-triazine-2,4,6(1H,3H,5H)-trione) has been determin ed by X-ray diffraction methods. The structure is built up of neutral [Cu(phen)2(HL)] entities (which are associated to form dinuclear units through hydrogen bonds involving the cyanurate ions), uncoordinated p henanthroline and crystallisation water molecules. The copper atom is involved in a CuN5 chromophore, with an stereochemistry near to a comp ressed trigonal bipyramid (TBP) but with a significant degree of disto rtion towards the square pyramidal (SP) topology. The EPR spectrum is indicative of a mixed d(z2)/d(x2-y2) groundstate for the copper(II) io ns in agreement with the structural data. No exchange coupling has bee n detected down to 4.2 K by means of magnetic susceptibility measureme nts. This feature is discussed on the basis of the bridging network. ( C) 1998 Elsevier Science Ltd. All rights reserved.