Straight-chain Or Propeller-like Complex Structure And Performance

Three new series of ligands including N,N'-bis(4-pyridylcarboxyl) -2,6-pyridine dicarbohydrazide, pyridylaromatic-hydrazone, and alkylpyridyl benzimidazole have been synthesized. The ligand N,N'-bis(4-pyridylcarboxyl) -2,6-pyridine dicarbohydrazide (H4L) is a propeller-shape multi-dentate ligand containing four amide moieties and three pyridine groups, and is expected to adopt diverse coordination modes according to the different geometric requirements of the metal ions. Three new complexes : 1.[Cd(H2L)1.5H2O]n, 2.[Cd(H2L)]n and 3. [Pb(H2L)]n were obtained through the reaction of the ligand with the corresponding metal ions. The second kind of ligands include 4,5-diazafluorene-9-one isonicotinoyl hydrazone(G); 4,5-diazafluorene-9-one malonichydrazone(F), and 2-hydroxy-3-methoxybenzaldehyde-2,6-pyridinedicarboxylhydrazone(SX). This kind of ligands contain multiple nitrogen and oxygen atoms which can generate diverse novel complexes by coordinating with the metal ions. The crystal structures of complex 4.[ZnG2(H2O)2]2H2O and ligands F and SX were determined. The third kind of ligand is of alkylpyridylbenzimidazole including l,4-bis[2-(2-pyridyl)benzimidazole] buane (ML), l,5-bis[2-(2-pyridyl) benzimidazole] pentane(FL) and l,6-bis[2-(2-pyridyl) benzimidazole]hexane(ST). By the reaction of the ML and FL with the different metal ions, eight novel crystal structures of the complexes: 5.{[CdML(NCS)2](DMF)2}n, 6.{[ZnML(NCS)2](DMF)2}n, 7.{[MnML(NCS)2](DMF)2}n, 8.{[CuML(NCS)2](DMF)2}n , 9.[Co(0.5ML) (H2O)3SO4]CH3OH, 10.[CoFLH2OSO4] 0.5DMF, ll.[CoFLSO4] 0.5DMF, 12. [CuFLSO4] 0.5DMF were yielded.When the Cd( II) and H4L react in different solvent, two three-dimensional polymers 1 and 2 with different structure were resulted. The center ions of these two complexes are both seven coordinated with a coordination geometry of distorted pentagonal bipyramid. The only difference lies in that the coordinate atoms in the axial sites are different. In complex 1, the pyridyl nitrogen atom and amide carbonyl oxygen atom are in the axial sites, while in complex 2 the axial sites are occupied by two pyridyl nitrogen atoms, which makethe former complex belong to hexagonal with space group P6(2) and the latter is trigonal with space group P3(l)2(l). It is interesting to note that complex 1 exhibits intense yellow-green emission when excited with near-UV radiation, however in complex 2 no emission can be detected. The complex 3 belongs to triclinic with space group P-l. The center ions are six coordinated with a coordination geometry of distorted octahedron. A ladder chain structure forms along the c direction.The complexes 5-8 are obtained through the reaction of the ligand ML and Cd( II), Zn( II), Mn( II) and Cu( II) ions. They are iso-structure and all belong to triclinic with P-l space group. The center ions are all six coordinated with a coordination geometry of distorted octahedron which make the complex form one-dimensional chain structure in the direction of c. There is a strong ji-ji stacking interaction between pyridylbenzimidazole rings in the adjacent chains. The complex 9 is obtained through the reaction of the ligand ML and Co( II) which belongs to monoclinic with P2(l)/n space group.The complexes 10-12 are obtained through the reaction of the ligand FL with Cu( II) and Co(II) ions. They are similar in crystal structure and all belong to triclinic with P-l space group. These three complexes are all dimmers with ring structure and a disordered DMF molecular lies in the ring. The complexes 10 and 11 are different crystal structures through the reaction of FL and Co ion reacting in different circumstances. Their center ions are both six coordinated with a coordination geometry of distorted octahedron. They are different because SO42" is monodentate in complex 10 and bidentate in complex 11. The center ions of the complex 12 is five coordinated with a coordination geometry of distorted tetragonal pyramid. The SO42" is also monodentate in complex 12. The hydrogen bonds between the SO42", the water moleculars, the DMF moleculars and the alkyl moieties make the molecular structure form into two-dimensional network in these three complexes.