RESUMO
The impact of metalloligands on Au catalysed alkyne hydrofunctionalisation is studied. Ambiphilic PMP-type ligands (M = CuI, AgI, ZnII) stabilise Au â M bonds including unprecedented AuI â ZnII interactions. The Lewis acidity of Au increases in the order CuI < AgI < ZnII promoting catalytic cycloisomerisation of propargylamide 14. Au/Zn complex 8 is an excellent catalyst for alkyne hydroamination.
RESUMO
Catalytic conversion of CO2 and hydrogen to methanol was achieved in a self-separating multiphasic system comprising the tailor-made complex [Ru(CO)ClH(MACHO-C12 )] (MACHO-C12 =bis{2-[bis(4-dodecylphenyl)phosphino]ethyl}amine) in n-decane as the catalyst phase. Effective catalyst recycling was demonstrated for the carbonate and the amine-assisted pathway from CO2 to methanol. The polar products MeOH or MeOH/H2 O generated from the catalytic reactions spontaneously formed a separate phase, allowing product isolation and catalyst separation without the need for any additional solvent. In the amine-assisted hydrogenation of CO2 , the catalyst phase was recycled over ten subsequent runs, reaching a total turnover number to MeOH of 19200 with an average selectivity of 96 %.