A NEW STRONTIUM-COPPER ETHYLENE-GLYCOL COMPLEX - SYNTHESIS AND STRUCTURE OF [SR(C2H6O2)(5)][CU(C2H4O2)(2)]CENTER-DOT-C2H6O2

A new crystalline strontium-copper ethylene glycol complex has been is olated and structurally characterized by single-crystal X-ray diffract ion. The solution-phase complex has also been investigated as a possib le molecular precursor for use in sol-gel synthesis of SrCuO2. [Sr(C2H 6O2)(5)][Cu(C2H4O2)(2)]. C2H6O2 has been isolated by crystallization f rom an ethylene glycol/methylethylketone solution of the strontium-cop per salt. Crystallographic data are as follows: orthorhombic, space gr oup Pna2(1), a=18.494(3), b=9.3076(8), c=16.615(3) Angstrom, V=2860(2) Angstrom(3), Z=4, R=0.044. In this molecule, copper is coordinated by two bidentate ethylene glycolate ligands in roughly a square planar g eometry. Strontium is coordinated by three bidentate ethylene glycol m olecules and two monodentate ethylene glycol molecules; the eight-fold coordination resembles a highly-distorted square antiprism. An additi onal ethylene glycol of crystallization is present which does not dire ctly coordinate the strontium ion. Copper and strontium ion complexes are held together by hydrogen bonding. The solution-phase bimetallic c omplex is hydrolytically unstable, giving rise to a 'muddy' brown prec ipitate upon exposure to water. The apparent decomposition is in direc t contrast with hydrolysis of similar barium-copper complexes which gi ves rise to stable blue gels. This decomposition made the strontium-co pper diol complex unsuitable for use in alkoxide sol-gel synthesis of strontium-copper oxides.