Synthesis and characterisation of polyoxotungstate compounds with complex copper and cobalt cations

Salts of the heteropolytungstates [PW11M(H2O)O-39](5-)(,) M=Cu, Co, Mn, wit h the following complex cations were prepared: [Cu(LL)(2)(H2O)](2+) , [Cu(L L)(3)](2+) , LL=1,10-phenantroline (phen), 2,2 ' -bipyridine (bipy), [Cu(ph en)(2)Cl](+), [CO(bipy)(2)(CO3)](+), and [Co(phen)(3)](2+). Compounds with [SiW11M(H2O)O-39](6-), M = Cu, Co, Mn, and the cations [Cu(LL)(2)(H2O)](2+) , and [CO(bipy)(2)(CO3)](+) were also prepared. Synthesis was carried out i n aqueous or nitromethane solutions. The compounds were characterised by el emental and thermal analysis and spectroscopic techniques. Spectroscopic pr operties and the thermal stability of the polyanions; in these compounds co uld thus be compared with those of simpler Salts. BET surface areas were de termined. Except for salts of [Cu(bipy)(3)](2+), the compounds decompose on heating at temperature above 200 degreesC, the exact temperature depending on the cation. Some are stable up to 300 degreesC. For salts of the [Cu(LL )(2)(H O-2)](2+) cations, more detailed thermal studies were performed, bas ed on the infra red spectra of the decomposition products obtained at sever al temperatures.