Syntheses and Structural Characterization of Lithium Carboxylate Frameworks and Guest-Dependent Photoluminescence Study

Five novel 3D lithium organic frameworks, [Li-2(H(2)pml)]center dot C4H8O2 (1, H(4)pml = 1,2,4,5-benzenetetracarboxylic or pyromellitic acid), [Li-2(H(2)pml)] (2), [Li(H(2)tatab)]center dot 5H(2)O (3, H(3)tatab = 4,4',4 ''-s-triazine-1,3,5-triyltri-p-aminobenzoic acid), [Li-11(H3O)(H2O)(5)(Html)(6)]center dot 8C(4)H(8)O(2) (4, H(3)tml = 1,2,4-benzenetricarboxylic or trimellitic acid), and [Li{Li(nmp)}{Li(H2O)(nmp)}{Li(nmp)(2)}(2)(H(2)tms)(Htms)(2)]center dot NMP center dot EtOH H(3)tms = 1,3,5-benzenetricarboxylic or trimesic acid, nmp = 1-methyl-2-pyrrolidinone), were synthesized by solvothermal methods and characterized by single crystal X-ray diffraction, powder X-ray diffraction (PXRD), IR spectroscopy, and thermogravimetric analyses (TGA). Compounds 1 and 2 feature the same framework composition but different guest-controlled structures and topology. Compound 4 consists of a unique undecanuclear Li carboxylate complex {L-11(H2O)(5)(RCOO)(18)} and contains pores with diameter 7 angstrom. Furthermore, compound 4 demonstrates highly pronounced guest-dependent photoluminescence behavior: nitrobenzene completely quenches the light emission, while toluene enhances it.