X-RAY CRYSTAL-STRUCTURE AND ELECTRONIC-PROPERTIES OF CHLOROBIS(MEPIRIZOLE)COPPER(II) TETRAFLUOROBORATE (MEPIRIZOLE EQUALS HOXY-3-METHYL-1H-PYRAZOL-1-YL)-6-METHYLPYRIMIDINE)

The crystal structure of [Cu(mep)(2)Cl](BF4) [mep = hoxy-3-methyl-1H-p yrazol-1-yl)-6-methylpyrimidine] has been determined by X-ray diffract ion. The crystal structure is built up of [Cu(mep)(2)Cl](+) cations an d BF4- anions. The structure of the cation involves a five-coordinated CuN4Cl chromophore, with a stereochemistry near to a compressed trigo nal bypyramid (TBP) but with a significant degree of distortion toward s the square pyramidal (SP) topology. The EPR spectrum is indicative o f a mixed d(z)2/d(x)2(-y)2 ground state for the copper(II) ions, in ag reement with the structural data. Copyright (C) 1996 Elsevier Science Ltd