Metallogels and Silver Nanoparticles Generated from a Series of Transition Metal-Based Coordination Polymers Derived from a New Bis-pyridyl-bis-amide Ligand and Various Carboxylates

Abstract

A new series of coordination polymers, namely, CP2 [{(H2O)Co1.5(μ-3-bpna)1.5(μ-btc)}·3DMF·3H2O]α, CP3 [{Cd(μ-3-bpna)(μ-hbtc)}·CH3OH·2H2O]α, CP4 [{Co(μ-3-bpna)(μ-ipa)}·DMF·2H2O]α, CP5 [{Co(μ-3-bpna)(μ-1,3-pda)}·DMF]α, CP6 [Cd(μ-3-bpna)0.5(μ-1,3-pda)]α, CP7 [(H2O)Co0.5(μ-3-bpna)0.5(μ-1,4-pda)0.5]α, and CP8 [{Zn(μ-3-bpna)(μ-oba)}·DMF·2H2O]α, has been synthesized by reacting a hydrogen-bond-functionalized bis-pyridyl ligand, namely, N′,N″-di(pyridin-3-yl)naphthalene-2,6-dicarboxamide, with various transition metal salts and different di- or tricarboxylates (as co-ligand) displaying 2D and 3D network topology and having lattice-occluded solvents in the majority of cases. A 1D coordination polymer, namely, CP1 [{Ag0.5(μ-3-bpna)}0.5·0.5BF4·CH3CN]α, has also been isolated by reacting 3-bpna with AgBF4 in the absence of any carboxylate co-ligand. All of the CPs were characterized by single crystal X-ray diffraction. Interestingly, two such CPs, namely, CP1 and CP2, produced metallogels, which were characterized by rheology, transmission electron microscopy, and X-ray powder diffraction. The metallogel of CP1 produced Ag nanoparticles within the gel bed upon exposure to light.