Syntheses, Structures And Luminescent Properties Of New Organic-Inorganic Coordination Polymers Generated From Oxadiazole-Containing Ligands Or Fulvene Ligands

The chemistry of organic-inorganic coordination polymers has recently become area of increasing interest. Self-assembly of organic ligands and inorganic metal ions is one of the most efficient and widely used approaches for the construction of organic-inorganic composite materials. In this paper, we wish to report the syntheses, structures and luminescent properties of 19 new organic-inorganic coordination polymers generated from 1, 3, 4-oxadiazole-containing ligands or fulvene ligands. A. The coordination chemistry of 1, 3, 4-oxadiazole-containing ligandsThe coordination chemistry of the oxadiazole-containing ligands 2,5-bis(4-pyridyl)-l, 3, 4-oxadiazole (L1) , 2,5-bis(3-pyridyl)-1, 3, 4-oxadiazole (L2) and 2.5-bis(4-aminophenyl)-1, 3, 4-oxadiazole (L3) with inorganic Ag(I), Cu(II) and Co(II) salts has been investigated. 16 new coordination polymers were prepared by solution reactions and fully characterized by IR. elemental analysis, TGA-DTA and single-crystal X-ray diffraction.(a) [Ag(L1)]SO3CF3 (1), [Ag(L1)](ClO4)(CH3OH)o.5(H2O)0.5 (2), [Ag(Ll)]NO3 (3), Ag(L2)(SO3CF3) (4) [Ag(L3)]SO3CF3 (5) were synthesized by combination of ligands L1-L3 with AgSO3CF3, AgC104, AgNO3 and AgSbFe, respectively.(b) The coordination chemistry of L1-L2 with Cu(OAc>2H2O, Cu(ClO4)2.XH2O, Cu(SO4).5H2O and CoSO4'7H2O were investigated. Nine new coordination polymers with novel polymeric motifs, namely [Cu2(OAc)4(L2)] (6), [Cu2(OAc)4(L,)]-3H2O (7), [Cu(L2)(H2O)3(SO4)]-2.75H2O (8), [Cu(hfacac)2(L2)] (9), Cu(L2)2(ClO4)2 (10), [Co(L,)(CH3OH)2(SO4)] (CH3OH)(H2O)3.5 (11), [Cu(L1)2](C1O4)2(CH3OH)(H2O) (12), Cu(L1)2(H2O)3(ClO4)2-H2O (13) and Cu(Li)(H2O)(S04)]-2(H2O) (14), were synthesized based on them, respectively.(c) Two novel chiral Cu-containing 3-fold interpenetrating three-dimensional coordination polymers, namely [Cu(Ll)2(H2O)](ClO4)2]-solvate (15, RT form) and [Cu(Ll)2(H20)](ClO4)2-solvate (16, LT form) were obtained by thecombination of L1 with CuC1O4-6H2O in a CH2C12/CH3OH mixed solvent system. An interesting structural transformation between them at room (293K.) and low temperature (150K) was found.B. Synthesis of fulvene ligands and their coordination chemistryNew type of rulvene ligand L6 was synthesized by Heck-coupling reaction. Its coordination chemistry with "soft" Ag(I) metal ion was also investigated. Three new Ag(I)-fulvene polymeric compounds, namely Ag(L4)2(PF6)-CeH6 (17), Ag(L5)2(SbF6)-2C6H6 (18) and Ag(L6)(BF4)-CH2Cl2-CH3OH (19), were synthesized based on ligands L4-L6, respectively.C. The luminescent properties of organic ligands L1, L2 and L6 and also selected polymeric compounds (1, 6, 7, 15 and 19) were investigated in the solid state. The results have shown that the emission wavelength and intensity of free organic molecules were affected by their incorporation into the metal -containing polymeric compounds.The results reported herein demonstrate that the use of 1,3,4-oxadiazole-containing or fulvene-type organic spacers as precursors to bind transition metal ions, is in fact a new approach for the formation of novel supramolecular networks with interesting physical properties.