Synthese, Structures And Properties Of Transition Metal Complexes Based On N-heterocyclic Ligands

In recent years, the design and synthesis of organic-inorganic hybrid complexes are of continuous interest not only for their fascinating structural diversity but also for their potential applications in chemical engineering, chemistry and materials science including gas storage, catalysis, luminescent and conductive materials. The aim of this thesis is the synthesis of new organic-inorganic hybrid complexes based on six N-containing heterocyclic ligands [dipyrido[3,2-f:2’,3’-h]-quinoxaline(Dpq),4,4’-bipyridine(bpy),1,10-Phenanthroline monohydrate(phen),3,5-bis(3-pyridyl)-4-amino-1,2,4-triazole(3-abpt),3,5-bis(4-pyridyl)-4-amino-1,2,4-triazole(4-abpt) and benzimidazole(C7H6N2)]. Thirteen new coordination complexes have been synthesized on the basis of hydrothermal technique or slow diffusion method.1. Two new isostructural tetranuclear Ag(I) complexes, formulated as [AgX(Dpq)]4(X=I, Br), were synthesized by slow diffusion method for the first time. The Ag ions within the molecule are bridged by four μ2-X-ions, forming a distorted [Ag4X4] ring structure which shows a molecular square architecture. The Dpq units in the tetrameric structures are found to stack in almost parallel and display π-π stacking interactions. Moreover, Ag… Ag interactions are observed in both complexes. Density functional theory and time-dependent density functional theory calculations at the B3LYP/LanL2DZ*+6-31G*level were performed on these tetranuclear Ag(I) complexes to rationalize their experimental absorption spectra. Moreover, the luminescence properties as well as thermal behaviors of these complexes were also investigated.2. Three new mononuclear Cu(I)/PPh3complexes, formulated as [CuX(Dpq)(PPh3)](X=I, Br, CN) were synthesized by slow diffusion method for the first time. These complexes are isostructural and have similar structures. It is worth mentioning mat the Dpq ligands of two adjacent molecules in these complexes are essentially parallel and display a favorable pairwise π-π stacking. And these adjacent enantiomeric molecules combine to form a supramolecular ABAB…aggregate. These complexes exhibit intense luminescence in ethanol solution at room temperture. Also, density functional theory and time-dependent density functional theory calculations at the B3LYP/LanL2DZ*+6-31G*level were performed on these complexes to rationalize their experimental absorption spectra. 3. One new Ag(I)/PPh.3complex was synthesized by slow diffusion method. This dinuclear Ag(I) complex exhibits an interesting one-dimensional zigzag chain structure. Ag…Ag interactions are observed in this complex. Density functional theory and time-dependent density functional theory calculations at the B3LYP/LanL2DZ*+6-31G*level were performed on this complex to rationalize its experimental absorption spectra. Furthermore, the luminescence property and thermal behavior of this complex were also investigated.4. Two new W/S/Cu clusters have been first constructed by [WOS3Cu2] as building units and bidentate ligand phen as the connector. It is worth mentioning that the phen ligands of two adjacent molecules in these clusters are essentially parallel and display π-π stacking interactions. These clusters have different crystal packing mode because of cotaining different solvent moleculars. Morever, the luminescence properties of these clusters were also investigated.5. Three new organic-inorganic hybrid complexes with3-abpt and4-abpt have been synthesized by slow diffusion method. The two Cu(I) complexes based on3-abpt ligand show different structures, one is a2D polymer which contains{Cu4I4} clusters and the other is a1D polymer. The Co-complex features a1D infinite chain structure. These complexes exhibit intense luminescence in ethanol solution at room temperture.6. Solvothermal reactions of different metal salts with benzimidazole and2,6-pyridinedicarboxylic acid in H2O afford two new coordination complexes. Morever, the luminescence properties of these complexes were also investigated.