Selected controlled synthesis of three-dimensional 4d-4f heterometallic coordination frameworks by lanthanide carboxylate subunits and silver centers

By control of mixed ligands with particular coordination sites, three novel three-dimensional (3D) 4d-4f heterometallic coordination polymers, [Ln(4)(H2O)(2)Ag(1,3-bdc)(4)(inic)(5)] center dot nH(2)O (Ln) Nd ( 1), n = 0.25; Eu ( 2), n = 0; 1,3- H(2)bdc = 1,3-benzenedicarboxylic acid and Hinic) isonicotinic acid) and [Nd(H2O) Ag(1,2-bdc)(inic)(2)] ( 3) (1,2-H(2)bdc) 1,2-benzenedicarboxylic acid), have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR, thermogravimetric (TG) analysis, and single-crystal X-ray diffraction. Compounds 1-3 crystallize in the monoclinic system, space group C2/c. Compounds 1 and 2 are isostructural and exhibit novel 3D coordination frameworks constructed from two-dimensional (2D) wavelike lanthanide carboxylate layers and Ag( inic) 4 complexes. To the best of our knowledge, they represent the first examples of 3D 4d-4f heterometallic coordination frameworks, in which the transition metal complexes bond to a 3D lanthanide carboxylate supramolecular framework with nanometer-sized channels built up from 2D wavelike layers. Compound 3 possesses an unusual 3D framework based on linkage of neodymium-carboxylate chains and silver( I) centers by inic ligands. The difference between both kinds of frameworks can be ascribed to the geometry effect of benzenedicarboxylate. Furthermore, the luminescent properties of 2 were studied.