Tuning the framework flexibility and equilibrium of HRh(CO)2P2 active isomers in single-atom Rh/P&N-POPs catalysts for hydroformylation reactions

•P&N-POPs with diverse framework flexibility were afforded.•The coordination state surrounding single Rh sites were effectively regulated.•The equilibrium of ea/ee-HRh(CO)2P2 species confined in the flexible framework were tuned.•Efficient performance in hydroformylation reactions (19 olefins, TOF > 2000 h−1, l/b > 15.5).•Perspectives regulation strategy in preparation of single atom catalysts.