Polyamidoamine dendrimers, constructed on the surface of silica, were phosphonated by using diphenylphosphinomethanol, prepared in situ, and complexed to rhodium by use of [Rh(CO) 2 Cl] 2 . Excellent selectivities, favoring the branched aldehydes obtained from aryl olefins and vinyl esters, were observed by using the Rh(I) complex as the catalyst in hydroformylation reactions. The heterogeneous Rh (I) catalyst can also be recycled and reused without significant loss of selectivity or activity.

Hydrogenolysis of mono(cyclopentadienyl)-ligated rare-earth-metal bis(alkyl) complexes Cp′Ln(CH2SiMe3)2(THF) (Ln = Y (1a), Dy (1b), Lu (1c); Cp′ = C5Me4SiMe3) with PhSiH3 afforded the mixed hydride/alkyl complexes [Cp′Ln(μ-H)(CH2SiMe3)(THF)]2 (Ln = Y (2a), Dy (2b), Lu (2c)). The overall structure of complexes 2a−c is a C 2-symmetric dimer containing a planar symmetric Ln2H2 core at the center of the molecule. Deprotonation of ArOH (Ar = C6H2- t Bu2-2,6-Me-4) by the metal alkyl group of 2a−c led to formation of the mixed hydride/aryloxide derivatives [Cp′Ln(μ-H)(OAr)]2 (Ln = Y (3a), Dy (3b), Lu (3c)), which adopt the dimeric structure through hydride bridges with trans-accommodated terminal aryloxide groups. Complexes 3a−c swiftly reacted with CO2 to generate the mixed formate/carbonate complexes [Cp′Ln(μ-η1:η1-O2CH)(μ-η1:η1-O2COAr)]2 (Ln = Y (4a), Dy (4b), Lu (4c)). The two Cp′Ln fragments in these complexes are bridged by the formate and carbonate species, respectively, to form two square-pyramidal geometries around the metal centers. Furthermore, complexes 3a−c initiated the copolymerization of CO2 and cyclohexene oxide (CHO) under mild conditions to afford polymers with modest molecular weights and high carbonate linkages (92−99%).