Three new cobalt(Ⅱ) coordination compounds,[Co(3,3'-Hbpt)2(H2pm)(H2O)2]·2H2O(1),[Co(4,4'-Hbpt)(pm)0.5(H2O)]·3H2O (2) and [Co(3,4'-Hbpt)(pm) 0.5 (H2O)3]·2H2O(3)(3,3'-Hbpt=3,5-bis(3-pyridyl)-1H-1,2,4-triazole;4,4'-bpt=3,5-bis(4-pyridyl)1H-1,2,4-triazole,3,4'-Hbpt=3-(3-pyridyl)-5-(4'-pyridyl)-1H-1,2,4-triazole and H4pm=pyromellitic acid) have been synthesized by hydrothermal reactions.Single-crystal X-ray diffraction reveals that compound 1 has a one-dimensional (1D) chain network,2 exhibits a four-connected three-dimensional (3D) structure with 1D open channels encapsulated by water molecules,while 3 displays a regular two-dimensional (2D) architecture connected through 1D metal helical chains.In addition,the efficacy of compounds 1-3 as additives to promote the thermal decomposition of ammonium perchlorate (AP) is explored by differential scanning calorimetry (DSC).
A 3D mixed-valence Co(III)–Co(II) compound [Co9(bta)10(Hbta)2(H2O)10]n·[22(H2O)]n(1)(H2bta=N,N-bis(1H-tetrazole-5-yl)-amine) was hydrothermally synthesized by reaction of Co(NO3)2·6H2O with H2bta·H2O. Compound 1 consists of three kinds of distorted-octahedral [CoII(N4O2)] paramagnetic nodes which are separated by [CoIII(bta)2(Hbta)]2-/[CoIII(bta)3]3-diamagnetic linkers to generate a 3D porous metal-organic framework(MOF) with alternative ···Co(III)···Co(II)··· array and channels incorporating water molecules. Under an applied magnetic field of 4000 Oe, compound 1 exhibits slow relaxation of magnetization at low temperatures, giving △E/kB=30.00 K and τ0=2.0×10-8 s.
Five transition metal coordination compounds, [Mn2(8-qoac)E(bdc)(H2O)4](1)(8-qoacH=quinoline-8-oxy- acetate acid, H2bdc=benzene-1,4-dicarboxylic acid), [Zn4(8-qoac)4(bdc)2]n(2), {[CdE(8-qoac)E(Hip)2(H2O)2]·(H2O)4}n(3)(H2ip=benzene-1,3-dicarboxylic acid), [Pb3(8-qoac)2(bdc)1.5(HEO)Cl]n(4) and [Zn2(8-qoac)(8-ql)(bdc)]n (5)(8-Hql=8-hydroxyquinoline), were synthesized by hydrothermal syntheses of metal salts with benzenedicarboxy- lic acid and 8-qoacH. Compound 1 possesses a discrete dimer bridged by bdc2- ligand. Compound 2 presents a 2D layer network constructed from bdc2- linkers and 1D infinite ribbons, in which Zn(II) centers are bridged by 8-qoac- with a tetradentate binding mode. Compound 3 displays a 1D zigzag chain, with adjacent chains further connected via extensive O-H…O hydrogen bonds to generate a 3D supramolecular structure. Compound 4 shows a 3D framework containing trinuclear lead secondary building units and bdc2- linkers, in which a new coordination mode of 8-qoac- ligand is observed. In compound 5, Zn(II) ions are simultaneously bridged by 8-qoac-, 8-ql- and bdc2- ligands to form tetranuclear zinc units, which are further interlinked by bdc2- linkers to yield a 2D wave-like layer. Based on intrali- gand(IL)(π-π*) fluorescent emission, compounds 1--5 possess strong purple fluorescent emissions. In addition, the thermal stabilities of compounds 1--5 were studied.