Silver(I) complexes with a P–N hybrid ligand and oxyanions: synthesis, structures, photocatalysis and photocurrent responses

Reactions of a P–N hybrid ligand, N,N-bis(diphenylphosphanylmethyl)-3-aminopyridine (3-bdppmapy), with silver oxysalts including AgNO3, AgOAc, AgBz (Bz = benzoate) and AgSal (Sal = salicylate) under different reaction conditions give rise to seven coordination compounds {[Ag4(μ–η,η-NO3)2(μ–η,η2-NO3)2](3-bdppmapy)2}n (1), {[Ag4(μ–η,η2-NO3)4](3-bdppmapy)2}n (2), {[Ag2(μ–η2-OAc)(μ–η,η2-OAc)]2(3-bdppmapy)2}n (3), [Ag2(Bz)(μ–η,η2-Bz)(H2O)]2(3-bdppmapy)2 (4), {[Ag4(μ–η2-Bz)2(μ–η,η2-Bz)2](3-bdppmapy)2}n (5), {Ag(Sal)(3-bdppmapy)}n (6) and {[Ag4(Sal)2(μ–η,η2-Sal)2](3-bdppmapy)2}n (7). Single crystal X-ray analyses reveal that 1, 5 and 7 have similar 1D chain structures constructed by [Ag4(μ–η2-Ox)2(μ–η,η2-Ox)2] units (1: Ox− = NO3−; 5: Ox− = Bz−) or [Ag4(Sal)2(μ–η,η2-Sal)2] units (7) and double 3-bdppmapy bridges. Compound 2 has a 2D layer structure derived from [Ag4(μ–η,η2-NO3)4] units and single 3-bdppmapy bridges. 3 displays another 2D layer structure formed by [Ag2(μ–η2-OAc)(μ–η,η2-OAc)] units and double 3-bdppmapy bridges. 4 shows a discrete tetranuclear structure formed by two [Ag2(Bz)(η,η2,μ-Bz)(H2O)] units and a pair of 3-bdppmapy bridges, while 6 adopts a 1D chain composed by [AgSal] units and single 3-bdppmapy bridges. 6 and 7 as representative samples display high catalytic activity toward the photodegradation of rhodamine B (RhB) in water. Compound 7 shows a better photocatalytic performance than that of 6, which correlates well with the differences in their anodic photocurrent responses and their HOMO–LUMO energy gaps derived from the density function theory (DFT) calculations. The formation of 6 and 7 from AgSal and 3-bdppmapy provides a new approach to the design and assembly of Ag(I)-supported CPs with interesting structural architectures and higher photocatalytic activity.