Hydrotalcite docked Rh-TPPTS complexes as efficient catalysts for the arylation of 2-cyclohexen-1-one in neat water

Well defined layered-double hydroxides (LDH: Mg3Al–NO3/CO3, Mg3Ga–NO3/CO3, Zn2Al–NO3/CO3 and Zn2Ga–NO3/CO3) were prepared using typical procedures starting from Mg(NO3)2·6H2O, Zn(NO3)2·6H2O, Al(NO3)3·9H2O and Ga(NO3)3·H2O. Rh-TPPTS complex was prepared by simple complexation of a Rh precursor [Rh(cod)Cl]2 and TPPTS (3,3′,3″-phosphanetriyl benzenesulfonic acid) in water. The heterogeneization of the Rh-TPPTS complex was performed by anionic exchange between Rh-complex and LDH supports. The catalysts’ structures and the chemical composition were confirmed by chemical analysis, XRD patterns, XP, FTIR and DRIFT spectroscopy. LDH-substituted Rh-TPPTS heterogeneous catalysts showed good catalytic activity in the 1,4-addition of arylboronic acid to 2-cyclohexen-1-one.