| The coordination compounds have got more and more notice due to their diversified structure and multifunctional properties.Of cause, our research group is also in this huge team.The main work of our group is the MOFs which are constructed by pyridine carboxylic acid, aromatic carboxylic acid, neutral bridging ligands and transition metal ions, contain the properties of the gas adsorption, fluorescence detection, dye adsorption and photocatalytic degradation.This paper discusses the structure of 11 MOFs which are formed by 2-amino-1,4-benzene dicarboxylic acid,5-(2-pyridyl)-methoxyl isophthalicacid (5,2-PMIA),5-(4-pyridyl)-methoxyl isophthalicacid (5,4-PMIA) and the related properties contain fluorescence detection of organic solvent, benzene compound、some pesticides and zwitterion, gas adsorption and so on.The first part is mainly about the research progress of MOFs are constructed by 5,2-PMIA and 5,4-PMIA.And the fluorescence properties of MOFs.The second part shows two different kinds of MOFs which are constructed by 2-NH2bdc,4,4’-bis(imidazol-1-ylmethyl)biphenyl (bibp),1,3,5-tris(1-imidazolyl)benzene (tib).[Zn(2-NH2bdc)(bibp)]n (Compound 1) and [Cd(2-NH2bdc)(tib)]n (Compound 2). Each 2-NH2bdc2- moiety connects two Zn (Ⅱ) atoms in monodentate coordination modes to form one-dimensional (1D) chains, which were pillared by bibp ligands to construct a 3D structure. Further topological analysis reveal that 1 adopts 5-fold interpenetrating architecture belonging to Class Ⅰa, and is related to 4-connected dia net with a Schlafli symbol of 6.Compound 2, each 2-NH2bdc2- anion is associated with two Cd atoms with both deprotonated carboxylate groups adopting bidentate-chelating to form a typical 1D chain along the c axis, are further connected by divergent tib ligands to form 3D framework. The resulting structure of 2 is a binodal (3,5)-connected net with its Schlafli symbol of (42·65·83)(42·6).As a result of 2-NH2bdc, Compound 1 and 2 have very strong fluorescence characteristics. The study found that the possible mechanism of the significant quenching effect of Hg2+ is given here. Notably, in 1 or 2, the amino groups of 2-NH2bdc2- are not bonded to the Zn (Ⅱ) centers and thus extensively decorate the framework as free-standing donors for metal guests. Mercury ions (Hg2+) have a high complexation affinity to N atoms, by the coordination of Hg2+ with pedant amino motif of 2-NH2bdc2-, the N atom hybridization state of -NH2 is prone to change from sp2 in 1 or 2 to sp3 in Hg2+-incorporated 1 or 2, and therefore the amino moiety was deviated from the plane of benzene ring, which may decrease the delocalization degree of compound 1 or 2, minimizes the energy transfer efficiency from π to π* orbital within 2-NH2bdc2-, thus reducing the luminescent intensity. The quenching of 1 in the presence of Cr2O72- is probably because the electron-transfer transitions of Cr2O72- decrease the energy transfer from π to π* orbital within 2-NH2bdc2-.The third part illustration 5 MOFs which are constructed by 5-(2-pyridyl)-methoxyl isophthalic-acid (5,2-PMIA), and 4,4’-bis(1-imidazolyl)-biphenyl (bimb), 4,4’-bis(imidazol-1-ylmethyl)biphenyl (bibp), pentaerythrityl-tetrakis(4-pyridyl) ether (PETPE) and so on. [Zn(5,2-PMIA)(bimb)]n (Compound 3), [Zn(5,2-PMIA)(bbi)]n (Compound 4), and [Cu(5,2-PMIA)(bibp)o.5]n (Compound 7) have 2D network, [Co(5,2-PMIA)(bix)0.5]n (Compound 6); [Ni2(5,2-PMIA)2(PETPE)]n (Compound 5) is heterogeneous isomorphism with Ni(OCO)2 secondary building unit (SBU) have 3D network. Compound 3 and 4 showed strong fluorescence intensity, can detect solvent, nitrobenzene and zwitterion with the relatively low detection limit.The forth part shows 4 MOFs are constructed by 5-(2-pyridyl)-methoxyl isophthalicacid (5,4-PMIA) and neutral bridging ligands including imidazole and Pyridine. [Co2(5,4-PMIA)2(PETPE)0.5]n (Compound 8)、[Zn2(5,4-PMIA)2(bimb)]n (Compound 9) and [Mn2(5,4-PMIA)3.5]n (Compound 11) have 3D network, [Cd(5,4-PMIA)1.5]n (Compound 10) and [Mn2 (5,4-PMIA)3.5]n (Compound 11) just metal ions and 5,4-PMIA coordination. Compound 10 with Cd atom as the center, the Cd atom coordinate with 5,4-PMIA by the mode of μ1-η1:η0、μ1-η1:η1. The same mode with Compound 11. The 9 showed strong fluorescence intensity, can detect copper ion, nitrobenzene and iodine with the relatively low detection limit.The 8, we use 5,4-PMIA and PETPE coordination, one Co and one N on the PETPE coordination.Finally, by PLATON calculation, Compound 8 has 37% effective porosity, having one cavity of 9.944×15.29 A2 in the direction of b axis. Then we do experiments on the gas adsorption. |
PDF Full Text Request