STRUCTURE AND PROPERTIES OF HETEROMETALLIC ALKOXIDES CONTAINING COPPER(I)

The heterometallic Cu-I alkoxides Li4Cu4(OCMe(3))(8) (1) and Ba2Cu4(OCEt(3))(8) (3) were synthesized from the component single metal alkoxides in anhydrous THF solution. Only 1 sublimes without decomposition under vacuum (150 degrees C); 3 is non-volatile. Crystal structures were determined for 1, 3 and the previously reported Na4Cu4(OCEt(3))(8) (2). Compounds 1 and 2 have nearly identical M(4)Cu(4)O(8) cores consisting of two puckered M(2)O(2) rings related by a centre of symmetry and joined at the oxygens by two bridging copper atoms, and at the M edges by two nearly linear O-Cu-O units. Compound 3 has a Ba2(OR)(2) ring containing the centre of symmetry and is bridged by two Cu,(OR), units that are nearly perpendicular to the Ba2O2 ring. The two BaCu2O3 planes in 3 are parallel, but separated by 0.48 Angstrom A. Hydrolysis of compounds 1-3 in THF afforded an orange or orange-brown solid that was converted to the mixed metal oxide by thermolysis, but copper and Cu2O were also produced from the Li4Cu4(OCMe(3))(8) hydrolysis product.