MOLECULAR AND MAGNESIA-SUPPORTED TETRAIRIDIUM CARBONYL CLUSTERS - CHARACTERIZATION BY LASER RAMAN-SPECTROSCOPY

Laser Raman spectroscopy has been used to characterize a family of iridium cluster carbonyls, including [Ph4P][HIr4(CO)11], [K][HIr4(CO)11], [Ir4(CO)12],and [Ph4P]2[HIr8(CO)22] in methanol solution and in the solid state. A supported analogue of [HIr4(CO)11]- was prepared by adsorption of [Ir4(CO)12] on MgO that had been treated at 400-degrees-C. It was identified on the basis of comparisons with the Raman spectra of the molecular clusters listed above. High-quality Raman spectra were recorded for the MgO-supported [HIr4(CO)11]-containing 6 wt % Ir, but the Raman spectra of the MgO-supported [HIr4(CO)11]-containing only 1 wt % Ir are of such low quality that no clear identification of the supported species was possible.