Researches On The Metal-organic Compounds Based On 5-nitro-1,2,3-benzenetricarboxylic Acid:the Synthesesis, Structures And Properties

Coordination polymer based on organic ligands of carboxylate group as a new type of metal-organic compound has been developed rapidly in the recent years due to their potential application in ion exchange,gas storage,magnetism,fluorescence,photocatalysis,dye degradation,sensor,catalyst,electronic equipment,nonlinear optical material,drug delivery and storage.Carboxylic acid is a type of extensive multifunction organic ligand with multiple coordination sites,diversity coordination modes,bridging abilities and forming multinuclear SBUs(SBUs = secondary structure units)with metal ions by self-assembly in constructing metal-organic coordination polymers.Aromatic carboxylate ligands have been attracted most interests not only because of the characteristic of organic carboxylate ligands,but also for their unique advantage of the rigid plane of the benzene ring which can form the coordination polymers with high rigidity and good thermal stability.On the other hand,the N-donor ligands and derivatives with bridging abilities are also wide used in constructing metal-organic coordination polymers and supramolecular self-assembly chemistry.In this paper,the 5-nitro-1,2,3-benzenetricarboxylic acid and several N-donor neutral ligands of 1,1-(1,4-butanediyl)bis(imidazole),1,4-bis(imidazole-1-ylmethyl)-benzene,1,10-bis(imidazole-1-yl)decane)and 1,10-bis(1,2,4-triazol-1-yl)decane)are selected as organic building units,the transition metal ions of ZnⅡ,CdⅡ,CoⅡ were selected as the inorganic building units to synthesize the metal-organic coordination polymers by adjusting the ratio of the solvent,temperature and reaction time.Finally,six metal-organic coordination polymers,namely[Cd3(nbta)2(H2O)4](1),[Cd3(nbta)2(biim)2(H2O)2](2),[Cd3(nbta)2(bix)2(H2O)2]H2O(3),[Zn3(nbta)2(biim)3](4),[Zn6(nbta)4(btd)5](5)and[Co3(nbta)2(bid)(H2O)8]-4H2O(6)(biim = 1,1’-(1,4-butanediyl)bis(imidazole),bix＝1,4-bis(imidazole-1-ylmethyl)benzene,bid = 1,10-bis(imidazole-1-yl)decane),btd =1,10-bis(1,2,4-triazol-1-yl)decane),have been synthesized by solvent hydrothermal method.The compounds 1-6 have been characterised by X-ray diffraction,infrared spectroscopy and thermal gravity analysis.The photoluminscent and dye absorption properties of 1-6 have been also investigated.The X-ray diffraction show that the compounds 1 and 2 are both 2D layer frameworks,and compound 1 is further extended into a supermolecule 3D framework via intramolecular hydrogen bonding interations.Compounds 3 and 5 exhabit 3D frameworks based on 2D layers and bridging N-donor ligands.Compound 4 shows a 3D network with(3,4)-connected(3·6·7)(3·5·62·7·8)(3·52·6·8·9)(5·6·8·10·112)topology.Compound 6 revealsa 3D structure with a 103 topology.Moreover,the photoluminscent properties of compounds 1-5 have observed with the emission peaks at 603 nm for 1,517 nm for 2,564 nm for 3,533 nm for 4 and 531 nm for 5,respectively.Further,the absorption experiment demonstrated that the compounds 3-6 can absorb the CR with short time and high effectivity.The compounds 3 and 5 can also absorb MB and A07 with high effectivity,respectively.