Ship-in-bottle synthesis of anionic Rh carbonyls in faujasites

Direct carbonylation of [Rh(NH3)(5)Cl](2+) ion exchanged in sodium and potassium faujasites yields carbonyls, the composition of which depends on the extent of dehydration before carbonylation, and on the carbonylation temperature. Polynuclear anionic Rh carbonyls are formed at 25-100 degreesC, if the water amount is sufficient. Greenish color of the species created at 75-100 degreesC in NaX. KX and KY points to the [Rh-6(CO)(15)](2-) complex; at 50 degreesC a white carbonyl is formed in NaX which structure seems to differ from the green complex in CO configuration. The anionic character of this species also follows from the lower wavenumber of terminal CO ligands in X zeolites and in KY compared to polynuclear neutral Ph carbonyl formed in less basic NaY. Carbonylation at 70-100 degreesC after dehydration or carbonylation at 160-200 degreesC lead to the formation of [Rh(CO)(2)](+). This carbonyl reacts to the polynuclear complexes at 25-100 degreesC after readsorption of water vapors. Individual carbonyl types once formed can be interchanged by varying the temperature and water amount. In addition to the FTIR spectroscopy, UV/VIS measurements and mass spectrometric analysis of ammonia released during the thermal decomposition of carbonyls were also employed. (C) 2001 Elsevier Science B.V. All rights reserved.