Synthesis, Structure And Spectroscopic Properties Of Transition Metal Complexes Containing Nitrogen, Oxygen Trifurcated Ligands

How to choose appropriate ligand and metal ions and how to control reaction conditionsfor assembly of metal-organic frameworks possessing special structure and function is one ofchallenging missions of coordination and supramolecular chemistry. However, the factorsgoverning formation of the framework of complexes are complicated, include not only ligandstructures and coordination preference and the inherent properties of metal ions, but also anions,solvent effects, PH value, ratio of ligands and metal ions as well as the temperature of reaction.In order to investigate effect of these factors on formation of the framework of complexes,we choose three kinds of ligands, namely trifurcated terpyridine, tridentate-chelatingterpyridine-like and aromatic carboxylic acid. In the paper, we have designed and synthesizedtwo trifurcated terpyridine ligands with different terminal groups and a tridentate-chelatedterpyridine-like ligand, and obtained six single crystals of transition metal complexes andstudied their structures. It is found that ligand isomer, synthesis method and auxiliary ligandhave different extent effects on the structures of the complexs. In addition, the relations betweenstructures and photoluminescence also have been studied. Meanwhile, we also adoptedhigh-symmetry aromatic carboxylic acid ligand with transition metals to synthesize fivecomplexes, and studied anions, ratio of reagent and auxiliary ligand effect on the structures ofthe complexes in different degrees as well. The thesis is divided into three chapters.In the first chapter, concept, history, synthesis strategy and luminescence theory ofcoordination polymers are introduced in detail, especially the synthesis and importance of thecoordination polymers of pyridine-containing rigid ligand and 1,3,5-tricarboxylic acid aresummarized. What's more, the meaning of this work was also described.In the second chapter described mainly six novel, copper and zinc complexes containingligands 4′-(4-pyridyl)-4,2′:6′,4″-terpyridine (L1), 4′-(4-pyridyt)-3,2′:6′,3″-terpyridine (L2),2,6-bis(2-benzimidazyl)pyridine (L3)prepared under hydrothermal or layer diffusion methods.These complexes were characterized by elemental analyses, IR spectroscopy and X-raycrystallography. Single-crystal X-ray analyses showed that the complexes are assembled indifferent dimensions, specifically 1-3 in 3D, 4 in 1-D and 5-6 in O-D. The influence of ligandisomerization, synthesis method, coligand, H-bond and p-p interactions on the formation anddimensionality of these coordination polymers were also explored. In addition,a description on photoluminescence properties of five Cu(â… ) and Zn(â…¡) coordination polymers 1-5 in solid statehave been made.The third chapter focuses on the influences of stoichiometry, coexisting anions andauxiliary ligand on the overall formation of the frameworks of complexes polymers[Cd(HBTC)(H₂O)₂]_n(1), [Cd(BTC)(H₂O)]_n (BIBM)_0.5n·2nH₂O (2),[Cd₃(BTC)₂(BIMB)₂]_n·2nH2O(3), [Cu(phen)(H₂BTC)Cl]_n(4), [Cu₄(BTC)₂(OH)₂(H₂O)₂(phen)₂]_n·4nH₂O (5), which wereprepared by hydrothermal reaction and have been characterized by elemental analysis, IRspectroscopy, and X-ray crystallography. Single-crystal X-ray diffractions had shown thatcomplex 1 structured in a 2D sheet, 2 and 3 in 3D networks, and 4 and 5 in 1D chains.Comparison made among the compounds indicates that addition of auxiliary ligand BIMBinfluences the combination of carboxylic acids and metal ions and meanwhile the coordinationpreference and hydrolysis of anion influence also the structures of the complexes.