Ship-in-bottle synthesis of anionic platinum carbonyls (Chini complexes) was studied in zeolites of various Si/Al ratio and types -NaLSX, NaX, NaY, dealuminated Y, NaEMT, NaM, NaBEA and MCM-41. The effect of decationation of Y zeolites was also examined. The increasing Si/Al ratio led to the increase of Pt nuclearity, the decationation of Y zeolite did not affect the final carbonyl formed. Recarbonylation of platinum after removal of carbonyl ligands by mild oxidation resulted in anionic carbonyl identical with the primary complex, while some changes were found in samples recarbonylated after decomposition of primary carbonyls via mild heating in vacuum. The carbonylation process was examined in situ by FTIR spectroscopy; the carbonyl complexes were decomposed by programmed heating with mass spectroscopic analysis of gases released.