Poly[bis(2,2′-bipyridine-κ2N,N′)bis(μ6-2,4,6-trimethylbenzene-1,3,5-tricarboxylato)tricadmium(II)], a two-dimensional 'Kagomé dual' (kgd) sheet structure

The title metal-organic framework, [Cd(3)(C(12)H(9)O(6))(2)(C(10)H(8)N(2))(2)](n), has been synthesized by a solvothermal reaction. The Cd(II) ions are located in CdO(4)N(2) and CdO(6) six-coordinated environments, with the latter Cd(II) ion lying on an inversion centre. The 2,4,6-trimethylbenzene-1,3,5-tricarboxylate ligand (TMBTC) connects the Cd(II) ions to form a two-dimensional sheet incorporating hourglass-like [Cd(3)(COO)(6)] secondary building units (SBUs). Topologically, taking the TMBTC ligand and the [Cd(3)(COO)(6)] SBU as 3- and 6-connected nodes, respectively, the overall two-dimensional sheet can be simplified to a rare (3,6)-connected 2-nodal kgd (Kagomé dual) net with a short Schläfli vertex notation of {4(3)}(2){4(6).6(6).8(3)}, which further stacks into a three-dimensional supramolecular framework through π-π stacking interactions.