Well-designed Syntheses And Luminescent Properties Of Organic Supramolecular Crystal Networks Based On Arenesulfonic Acids

Organic supramolecular crystal networks(OSCNs) have attracted extensive attentions owing to their intriguing topological structure and excellent properties in the field of photochemistry, adsorption and separation, biomedicine and pharmaceutics. To date, many outstanding results have been achieved during the past decades, which provide some useful experiences for designing and synthesizing supramolecular compounds. However, the studies on organic sulfonic acid supramolecules started so late that many problems, such as directional designing and synthesizing, regulation of structure and properties, need to be solved urgently. Therefore, it is still a challenging subject to seek for effective organic molecular building blocks and solvent systems to construct OSCNs with novel architectures and good properties through different assemble processes.In this thesis, based on the summarization of topological structures and properties of reported sulfonic acid supramolecules, arenesulfonic acid with different structural features, aromatic amines and amino acids are selected as synthons according to the principle of crystal engineering and supramolecular chemistry to synthesize a series of OSCNs with novel structures and good luminescence properties, which then provide some valuable experiences for designing and synthesizing such types of supramolecules. Herein, forty-five organic sulfonic acid supramolecules are synthesized in series of conventional solvents by natural evaporation and gridding methods. Their supramolecular patterns, crystal networks and luminescence properties are then systematically characterized. The main research results include the following aspects:1. Nine OSCNs were obtained by the liquid phase self-assemble reaction of rigid 1,5-NDS and TPMA in a series of solvents with different volume, polarity and ability for building hydrogen bonds. Meanwhile, after being immersed in aqueous solution for a month, the products of 9 heated at 50 and 120 oC can convert into another two new compounds 10 and 11. In different solvents, four types of intriguing supramolecular patterns constructed by –SO3-and –NH3+ groups are formed, that is, discrete motifs for 4-8, 11, 1-D tapes for 1, 3 and 10, 2-D layer for 2, and wheel motif for 9. Then, these patterns are further connected through naphthyl rings in different orientations to construct seven types of packing diagrams. For the small molecule H2 O, high symmetric structure of compound 9 with regular hexagonal channels was obtained. The network transformation of 9 is irreversible during the adsorption and desorption of water molecules. The eleven salts exhibit different luminescent emissions with the maximum varied from 382 to 393 nm under the effect of different solvents and networks in these compounds. Moreover, the luminescence emissions of compounds 10 and 11 are higher than that of compound 9.2. When the semi-rigid 4,4-biphenyl disulfonic acid with long spacer and TPMA are selected as building blocks, fourteen OSCNs were obtained in a series of pure solvents and mixed water/solvents by liquid phase self-assembly. The compounds crystallized from diverse synthesis systems have different sensitivities to water molecules. For the pure solvents, interesting supramolecular patterns were constructed from –SO3- and –NH3+ groups. Solvent molecules with both hydrogen bonding donors and acceptors tend to result in single or double chain structures(12-17). In comparison, the solvents with hydrogen bonding acceptors lead to discrete(19), chain(18) and layer(20) structures. To the mixed solvents, the supramolecular patterns are regulated by H2 O molecules with diverse HB2’, HB3’ and HB4 modes. Compounds 21 and 25 exhibit single chain structure while compounds 22-24 show layer structures with nano quadrangular windows. Furthermore, the abovementioned supramolecular patterns are connected by biphenyl rings in different orientations to generate eight types of packing diagrams. The thirteen compounds exhibit different emission intensity with the maximum varied from 343 to 359 nm as the change of solvent molecules. Especially, the introduction of water molecules can further enhance the luminescence emission intensity of compounds.3. A new synthesized synthon, 4,4’-dihydroxybiphenyl-3,3’-disulfonic acid(H4M), was used to construct twelve OSCNs with TPMA in a series of solvents by liquid phase self-assembly and gridding methods. Compound 30 can transfer into 31 through single-crystal-to-single-crystal transformation. Solvent molecules have important impact on the supramolecular patterns formed by –SO3- and –NH3+ groups and result in the formation of discrete [2+2] motif(37 and 38), [4+4+6] cluster(29), as well as 1-D ???(–SO3)???(–NH3)???(solvent)??? chain(27, 28, 31 and 36) and tape(30, 32, 33-35) structures. These patterns are further extended by biphenyl rings in different orientations and conformations to generate five types of packing diagrams, in which the two –SO3-groups of H2M2- in salt 31 adopt cis conformation. During different assembly process, small solvent molecules tend to form different structures(27 and 28, 29 and 30) while large molecules usually present the same structures(32-38). In addition, the eleven compounds exhibit different emission intensity with the maximum varied from 365 to 371 nm.4. Seven chiral OSCNs were prepared in mixed water/methanol solution by the reaction of rigid conjugated 1,5-NDS and a series of chiral α-amino acids. Compound 45 can change into 44 through single-crystal-to-single-crystal transformation and the configuration of the H2His2+ cations varies from R to S. The –SO3- and –NH3+ groups can form diverse [(SO3)x(NH3)y] discrete motifs(x or y = 1, 2; 39、41、43、44), single and double chains(42), as well as 3D networks(40) under the regulation of different substituents of amino acids. Then, naphthyl rings in different orientations connect these aforementioned supramolecular patterns to generate five kinds of packing diagrams. Furthermore, the six compounds exhibit stronger emission than that of 1,5-H2 NDS and corresponding α-amino acids with the maximum varied from 342 to 402 nm. Some compounds(42 and 44) exhibit various degree of blue-shift.