Rhodium-catalysed carbonylation of methanol using a new multifunctional ligand - Isolation and structural characterisation of the macrocycle [Rh2I6(CO)(2)(C6H4N3CH2CO2C4H2SCO2CH2C6H4N3)](2)

The new multifunctional ligand thiophene-2,5-bis(carboxyla-tomethylenebenzo triazole) (1) reacts with [RhCl(CO)(2)](2) to give the rhodium complex [RhC l(CO)(1)]2 (2), which was found to catalyse efficiently the iodide-mediated carbonylation of methanol. The macrocyclic carbonyliodorhodium complex [Rh 2I6(CO)(2)(1)](2) (3) was isolated from the catalytic mixture and structura lly characterised.