Carbonylation transition metal ions, zeolite

Transition metal ions, within the zeolite framework, may undergo a reductive carbonylation to give mononuclear monovalent carbonyl coumpounds M(I)(CO) and ultimatly to give zerovalent polynuclear carbonyl clusters. The rhodium(I)and iridium(i)carbonyIs were identified using spectroscopic and volumetric methods, the zerovalent rhodium and Iridium clusters M (CO)j were also synthetized in the zeolite matrix and their structure investigated using IR, NMR and spin labelling methods. 

Recently there have been numerous studies on gas-phase catalytic reactions induced by transition metal ion-exchanged zeolites such as reduction, oxidation, and carbonylation. The transition metal ions in zeolites are held to the zeolite framework by coordinating lattice oxide ions hence, the zeolite framework is considered to be a mono- to polydentate macro ligand for the... 

Gentle treatment under a CO atmosphere is sufficient to convert some transition metal ions in zeolites into zeolite entrapped metal carbonyl clusters. Such clusters are usually formed under milder conditions in faujasite cages than in solution. This comparison illustrates the excellent solvating abilities of the cages. 

The synthesis of phthallocyanines in zeolite Y has been the subject of several publications [52-58]. The different procedures are represented in Scheme 3. In principle, dicyanobenzene is reacted under inert conditions with transition metal zeolites. The latter can be prepared either via ion exchange, or via carbonyl or metallocene impregnation. 

The in-s rtu synthesis of metalio-phthalocyanines in zeolites can be done via three distinct literature procedures (Scheme 1). The required amount of a given transition metal is brought into the zeolite via a simple ion exchange (procedure A), through adsorption of a TM-carbonyl (B) or a metallocene (C). After removal of the respective TM ligands (water, CO and cyclopentadiene, respectively), 1,2-dicyanobenzene (DCB) is adsorbed onto the TM-zeolite and the mixture heated to form the MePc compiex. Rnally, the sample has to be purified in such a way that oniv occiuded MePc complex remains in the zeolite. The association of DCB with the supercage TM ions in Y zeolite, are schematically shown in Fig. 3. 

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