Two Novel One-Dimensional α-Keggin-Based Coordination Polymers with Argentophilic {Ag3}3+/{Ag4}4+ Clusters

Abstract

Two novel α-Keggin anion-based coordination polymers with argentophilic {Ag3}3+/{Ag4}4+ clusters, [{Ag3(bpy)4}{PMo12O40}]·2H2O (1), [{Ag(bpy)}2{Ag4(bpy)6}{PMo11VO40}][{Ag(bpy)}2{PMo11VO40}] (2), have been hydrothemally synthesized and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, and single-crystal X-ray diffraction. The crystal data for these are the following: C40H36Ag3Mo12N8O42P (1), triclinic P1̅, a = 10.5245(19) Å, b = 12.058(2) Å, c = 13.530(2) Å, α = 87.015(2)°, β = 72.146(2)°, γ = 86.563(2)°, Z = 1; C100H80Ag8Mo22N20O80P2V2 (2), triclinic P1̅, a = 13.3603(15) Å, b = 16.3035(18) Å, c = 16.7523(19) Å, α = 89.896(2)°, β = 84.000(2)°, γ = 88.066(2)°, Z = 1. Polymer 1 consists of an infinite zigzag one-dimensional (1D) chain constructed from [Ag3(bpy)4]3+ clusters and [PMo12O40]3− anions. Polymer 2 consists of isolated bisupporting [{Ag(bpy)}2{PMo11VO40}]2− anions and infinite 1D cationic chains [{Ag(bpy)}2{Ag4(bpy)6}{PMo11VO40}]2+ constructed from [{Ag(bpy)}2{PMo11VO40}]2− anions bridged via {Ag4(bpy)6}4+ clusters. Argentophilic {Ag3}3+ and {Ag4}4+ interactions exist in polymers 1 and 2. Ag···Ag interactions were proven using density functional theory, and the luminescent properties were investigated in polymers 1 and 2. The electrochemical behavior of the polymers modified carbon paste electrode (1-CPE, 2-CPE) and their electrocatalytic reductions of nitrite were investigated. Both 1-CPE and 2-CPE show good electrocatalytic activity toward the reduction of the nitrite and remarkable stability that can be ascribed to their insolubility.