Multinuclear coordination polymers based on Ag⋯Ag interaction: syntheses, structures, and luminescence properties

Abstract

A series of coordination polymers based on Ag⋯Ag interactions, namely, [Ag₂(hpyb)_0.5(L1)_0.5(NO₃)]·H₂O (1), [Ag₄(hpyb)(HL2)(NO₃)₂]·2H₂O (2), [Ag₃(hpyb)_0.5(L3)(NO₃)] (3), [Ag₆(hpyb)(L4)₂(NO₃)]·NO₃·2H₂O (4), [Ag₅(hpyb)_0.5(L5)₂(NO₃)]·H₂O (5), {Ag₄(hpyb)[L6(CH₃)₂]₂} (6), {Ag₆(hpyb)(HL7)₂[L7(CH₃)]} (7) and [Ag₃(hpyb)_0.5(HL8)]·H₂O (8) (H₂L1 = p-phthalic acid, H₃L2 = 1,2,3-benzenetricarboxylic acid, H₂L3 = cis-2-butenedioic acid, H₂L4 = 2,3-pyridinedicarboxylic acid, H₂L5 = m-phthalic acid, H₄L6 = 1,2,4,5-benzenetetracarboxylic acid, H₃L7 = 1,2,4-benzenetricarboxylic acid and H₄L8 = 4,4′-oxydiphthalic acid) has been synthesized. For compounds 1–4, the polycarboxylate anions bridge multinuclear Ag(I) units to form 1D chains, respectively. The chains are extended by π–π interactions into a 2D supramolecular layer for compound 3 and 3D supramolecular architectures for compounds 1, 2 and 4. Compound 5 displays a 3D (4,8)-connected (3⁴·4²)(3⁴·4¹²·5⁸·6⁴)₂ framework. Compounds 6–8 exhibit 2D layers, where the layers of 6 and 8 are further linked by π–π interactions to yield 3D supramolecular architectures. In the solid state, compounds 1–8 exhibit strong fluorescence emission bands at room temperature.