The Application Of CuAAC Click Reaction In The Synthesis Of Organic Functional Materials And Theoretical Calculations

The Nobel Prize Laureate-chemist Sharpless who works in the American Scripps Institute put forward in 2001 the concept of "click chemistry". Ever since then, "click chemistry" has rapidly gained tremendous attention across various fields, ranging from chemistry, biology, medicine to materials, etc. Click transformations are easy to perform, give rise to their intended products in very high yields with little or no byproducts, work well under many conditions, and are unaffected by the nature of the groups being connected to each other. In particular, the Copper-Catalyzed Azide-Alkyne Cycloaddition (CuAAC) reaction has been hailed as the cream of the crop. In this thesis, we applied the CuAAC reaction to the development of several new organic functional materials in a fast and convenient manner with high yield.The main contents and results are summarized as follows:In Chapter 1, the recent progress of click reaction is reviewed.In Chapter 2, resorting to "click chemistry", a series of photochromic dendrimers, A-Tri-SP, B-Tri-SP, C-Tri-SP and D-Hex-SP, were synthesized facilely in sound yields. The photochromic properties of these dendrimers were tested in both THF solution and in PMMA film. In addition, the effect of the complexation of Fe3+ on the thermal stability and two photon absorption properties of the open ring forms were studied. The results show that these dendrimers were demonstrated to be endowed with superior performance to the corresponding spiropyran monomer in terms of larger optical density, better stability of the open ring form, higher sensitivity in coordination with ferric ion and better two-photon absorption property. Specifically, the optical density of A-Tri-MC and D-Hex-MC were measured 2.88 times and 5.27 times larger than that of N3-MC. The MC forms of the dendrimer samples exhibited slower relaxation behavior due to the restraint movement of MC units. The dendrimers bearing multiple MC units offer higher sensitivity in coordination with Fe3+ and better stability of the MC-Fe3+ form. The two-photon absorption test showed that the two-photon absorption property of D-Hex-MC-Fe3+ is better than that of A-Tri-MC-Fe3+In Chapter 3, we designed and synthesized a starburst triphenylamine, tris(4-(1-(4-(dipheny lamino)phenyl)-1H-1,2,3-triazol-4-yl)phenyl)amine (TM), via straightforward'click coupling'of 4-azido-N, N-diphenylbenzenamine and tris(4-ethynylphenyl)amine. The optical, electrochemical, and thermal properties of TM were examined. Its electronic structure was studied by quantum mechanical approach. The synthetic strategy is straightforward and benefits from high yield of 92% and facile purification without tedious silica gel chromatography. TM emits deep blue fluorescence in both solution and solid state.It shows two reversible redox processes, suggesting a good hole-transporting capability. TM was proved to be a potential hole-transporting material and blue-light-emitting material. Compound 4-azido-N, N-diphenylbenzenamine is a novel triphenylamine derivative, which lends a new way for the functionalization of materials with triphenylamine by'click reaction'In Chapter 4, three organic dyes based on bisindolylmaleimide derivatives were synthesized. Their photophysical and electrochemical properties were examined. Their electronic structures were studied by quantum mechanical method. The nonplanar structure of bisindolylmaleimide was proven to be effective in aggregation resistance. Quantum chemical calculation proved the nonplanarity of these dyes and revealed the lack of electronic coupling between the dye excited state and the TiO2 conduction band, which may affect the quantum yield of charge injection. These dyes were investigated as sensitizers for the application in nanocrystalline TiO2 solar cells.In Chapter 5, the working mechanism for a redox-responsive bistable [2]rotaxane incorporatingα-cyclodextrin (α-CD) ring synthesized by'click' reaction was studied based on free energy profiles from all-atom molecular dynamics simulations. The free energy profiles (potential of mean force, PMF) were calculated for the shuttling motion of the a-CD ring between a tetrathiafulvalene (TTF) recognition site and a triazole (TZ) unit on the dumbbell of the rotaxane for three oxidation states (0,+1,+2) of the TTF unit in both vacuo and solution. While the calculated free energy profiles in vacuo can not explain the experimental results, the free energy profiles in solution verified the experimentally observed binding preference for each state, showing the importance of explicitly taking into account the water environment. Analysis of the free energy components reveals that, for theseα-CD based rotaxanes with charged TTF units, the real driving force for the shuttling in the oxidized states is actually the interactions between water and the rotaxane components, which overwhelms the attractive interactions between theα-CD ring and the charged dumbbell.In Chapter 6, Conclusion.