Browsing by Author "López, Concepción"

The reactions of iridium and rhodium complexes derived from tris(pyrazolyl)methane (tpzm) and tris(pyrazolyl)ethane (tpze) have been examined. One of the most interesting reactions involves the formation of alkoxycarbonyl derivatives of iridium tris(pyrazolyl)alkanes from carbon monoxide and alcohols. In the case of rhodium derivatives, a dimer of formula [(tpzm)iRh2 (CO)3](ClO4h has been obtained. A careful 1H and 13C NMR study has allowed assignment of all the signals of the compound [(tpzm)IrH(CO2Me)(CO)]BF4

The carbon-13 chemical shifts and tH-13C coupling constants of twelve polypodal ligands belonging to bis(pyrazol-1-yl)- and tris(pyrazol-1-yl)-methane classes are described. The chemical shifts show high internal consistency: for instance, a previously-reported additive model predicts, with great accuracy, the chemical shift of the central sp3 carbon. Coupling constants proved to be useful tools for the assignment of pyrazole carbons. The 11( 1 H-13C) coupling of the central carbon is linearly related to the basicity of the pyrazole substitutent in tris(pyrazol-1-yl)methanes.