6533b827fe1ef96bd1286eb4

RESEARCH PRODUCT

Crystal and molecular structure of tris(mepirizole) copper(II) hexafluorophosphate [mepirizole = 4-methoxy-2-5-methoxy-3-methyl-1h-pyrazol-1-yl)-6-methylpyrimidine

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Abstract The X-ray crystal structure of Cu(mep)3(PF6)2 [mep = mepirizole or 4-methoxy-2-(5-methoxy-3-methyl-1H-pyrazol-1-yl)-6 methylpyrimidine], obtained from stoichiometric quantities of mep, Cu(NO3)2 and KPF6 in water/ethanol solution was determined. The trisbidentate Cu(mep)32+ cation is observed for the first time. One of the three mep molecules is disordered over two sets of positions related by crystallographic symmetry. The mep molecules exhibit two different conformations A and B: conformation B, which is observed for the first time, derives from the usual conformation A by rotating the pyrimidine ring by 180° around the central CN bond and rotating by 180° the methoxy group bonded to the pyrimidine ring. The copper atom lies at the centre of an elongated CuN6 octahedron; mean equatorial CuN distances: 2.05 A; axial CuN distances: 2.43 A.IR, electronic and EPR spectra are interpreted on the basis of the above stereochemistry.