Polyoxometalate-based inorganic-organic hybrids based on a half rigid N-heterocyclic carboxylate ligand: Syntheses, structures and properties

Abstract Three new inorganic-organic hybrids constructed from a half rigid N-heterocyclic carboxylate ligand, K[Ag3(HL1)4](Mo8O26) (1), [Ag4(HL1)2(HL2)2(SiMo12O40)] (2) and (H3O)[Ag(L1)2]·2H2O (3) [HL1 = 1-(4-carboxylbenzyl)-3-(pyrazine-2-yl)pyrazole; HL2 = 3-(2-pyrazine)pyrazole], were hydrothermally synthesized and characterized. In compound 1, {K[β-Mo8O26]}n3n− chains fill in the channels of the 3D supramolecular network. In compound 2, HL1 and HL2 coordinate to Ag(I) ions into left- (L) and right-handed (R) helical chains, and (SiMo12O40)4- anions link two neighboring helical chains into a 2D layer structure. The crystal structure of compound 3 is stabilized by hydrogen bonds and π … π interactions, forming a 3D supramolecular network. The luminescent properties of the three compounds have been investigated. In addition, the electrochemical properties of compound 2 have also been investigated.