Band gap engineering of amine functionalized Ag(I)-based coordination polymers and their plasmonic Ag0 coupled novel visible light driven photo-redox system for selective oxidation of benzyl alcohol

We developed a one-pot synthetic route to design Ag nanoparticles (NPs) coupled mixed ligand Ag(I) coordination polymer (CP), Ag@Ag(I)-CP (40% NH2) for photocatalysis. Initial combined (experimental and DFT) study on mixed ligand CPs demonstrates that a rational substitution of ligand L1: 1,4-benzenedicarboxylate by L2: 2 amino 1,4-benzenedicarboxylate enhances porosity and reduction of energy gap (2.9 eV) due to highest occupied crystal orbital (HOCO; + 2.4 V vs. NHE) suitable for BA oxidation selectively to benzaldehyde (BD) ((E0 BA/BD = + 1.9 V). When Ag NP (~ 6–7 nm) is in-situ encapsulated on CP, formed a coupled structure Ag@Ag(I)-CP (40% NH 2), which offered advantages on BA oxidation (k (O2) = 7.4 × 10-4 min-1; yield: 19.1% BD, and k (persulfate) = 38.7 × 10-4 min-1; yield: 54.1% BD) along with significant stability, reusability and competitiveness than other Ag or precious metal NPs. The new material offers numerous possibilities for applications in oxidative organic transformations reactions. The simple synthetic strategy demonstrated in this work for the coupling of Ag(I) based coordination polymers with metal nanoparticles at the molecular scale for semiconductor like applications under visible light will accelerate extensive research in near future.