Syntheses, Structures And Properties Of Nitrogenous Bridged Chelate Dinuclear Complexes And Metal-organic Framework

Recently, metal complexes have attracted chemists’ attentionbecause of their glamorous structures, excellent proprieties, andextensive application in the luminescence, electromagnetic,catalysis and so on. The merit of uncomplicated manipulation, lowcost and highly stable final products for hydro(solvo)thermal reactionmakes it possible to gain more various complexes. This dissertationprimarily focuses on the study on the syntheses, structures andproperties of a series of diunclear metal complexes as well asmetal-organic frameworks constructed from N-donor bridged chelateligands. The main contents and results can be listed as follows.1. The development history, construction, research progressandof coordinated polymers based on nitrogenous bridged chelateligands are concisely introduced, while the inclusive interaction inthe metal complexes can be presented particularly.2. Five new complexes [Cu4(ppz)4(PO4)]·[CuBr2](1),[Cu4(ppz)4 -(MoO4)2(H2O)]·2H2O (2),[Cu(Hppz)(Mo2O7)](3),[Cu2(ppz)2(Mo3O10)](4)and[Cu (ppz)(PMo VM o VI6639O40)](5)(Hppz=2-(1H-pyrazol-3-yl)pyrazine)via hydrothermal synthesis method are reported, in which Cu(II) ionscan link with organic ligands through two bridge-nitrogen atoms intodinuclear secondary building unit (SBU){Cu2(ppz)2}. Besides, theunsaturated coordination sites in SBUs can facilely be occupied bythe auxiliary oxo groups of1~5from simple inorganic oxyacid topolynuclear metal-oxygen clusters, respectively, PO43-, MoO42-,[Mo2O7]-,[Mo3O10]2-and [PMo12O40]6-, which results in the formation of aseries of distorted coordinated polyhedron as a result of the strongerJohn-Teller effect of Cu(II) ions. Especially, it is a novel3D frameworkwith “pcu” topology for5that contains two parts, ie. cationic andanionic groups. The3D cationic nets with “NbO” topology exist1Dchannels viewed along the c-axis, while the [PMo12O40]6-anions arefilled in the channels, acting as not only a template, but also ahexa-dentate ligand. Additionally, the magnetic studies of1,3,4and5reveal that strong antiferromagnetic behaviors were detectedbetween two Cu (II) atoms in SBUs.3. The solvothermal reaction of CoCl2and2-(4-thiazolyl)-benz-imidazole (Htbi) in ethanol solution gave rise to two isomers, namely,[Co2(Htbi)2Cl4](6),(7), which show quite different isolated dinuclearstructures bridged by two chlorides. Density functional theory calculations manifest that the optimized geometric parametersmatch very well with the experimental ones for both isomers.Particularly, the experimental UV-vis absorption spectra in N,N-dimethyl acetamide for6and7show the same absorption bandsand match with the computed results. Nevertheless, the conspicuousdisparity of two calculated Gibbs free energies demonstrates thatintrinsic stability of6is superior to7, in agreement with their relativeyields under experimental conditions. Moreover, compound6basedon two octahedral and tetrahedral Co(II) atoms show strongantiferromagnetic behaviors.4. A concise conclusion and a perspective of this work weredrawn.