Tetracarbonyldichlororhodium(I) [Rh(CO)(2)(mu-Cl)](2) entrapped in faujasite type zeolites reacted with phosphines PMe3-xPhx at 393-463 K to a different extent. Although according to computational studies phosphines with x < 2 should be small enough to enter the micropore system, the reaction was in no case complete and led to a mixture of products as observed by IR spectroscopy. Furthermore surface-bonded rhodium carbonyl complexes were synthesized in mesoporous aluminium-containing MCM-41 material by reacting acetylacetonatodicarbonylrhodium(I) [Rh(acac)(CO)(2)] with Bronsted-acidic centers;under formation of a chemically bonded [Rh(CO)(2)]-species and acetylacetone according to IR spectroscopy. The corresponding surface-bonded phosphine complex [(O-s)(x)-Rh(chiraphos)] was synthesized and identified with IR and P-31 MAS NMR spectroscopy.