| Using a series of isomers of angular N-donor ligands 4-amino-3,5-bis（x-pyridyl）-1,2,4-triazole （x-bpt, x = 2, 3, 4） and the derivative N-（3,5-bis（3-pyridyl）-1,2,4-triazole-4-yl） nicotinamide （HL）, incorporating with various aromatic dicarboxylic acids such as isophthalic acid （H2ip）, as well as its 5-substituted derivatives, 5-hydroxylisophthalic acid （H3hip）, 5-aminoisophthalic acid （H4aip）, 5-nitroisophthalic acid （H2nip） and 5-sulfoisophthalic acid （H3sip）, and aliphatic malonic acid, four organic cocrystals and twenty metal-organic coordination complexes were prepared via metal-directed assemblies and structurally characterizated by X-ray diffraction.In ChapterⅠ, a brief introduction on the history and progress of crystal engineering, and the study focus, synthetic strategies, the correlations between coordination complexes and su-pramolecular organic cocrystals as well as our design strategies are given.In ChapterⅡ, the reaction of 4-bpt and various R-isophthalic acids （R = -H, -NH2, -NO2 and -SO3H） with different metal salts leads to the formation of four supramolecularcocrystals. In compounds [（H2ip）·（4-bpt）] （1） and [（H4aip）·（4-bpt）] （2）, the 1-D zigzag chains formed by synthon I （R22（7） containing classical O-H…N and weak C-H…O interactions） are extended to the 2-D wavelike and "W"-like layers, respectively. Compound [（H2nip）·（4-bpt）]·2H2O （3） displays fascinating helical chain. A double-strand array is gener-ated in [（H2sip）-·（H-4-bpt）+]·2H2O （4）, which is stretched to a 2-D sheet with ABAB packing fashion. Finally, the structures of 1-4 exhibit diverse 3-D arrays. Obviously, the structural discrepancy from 1-D to 3-D supramolecular nets among the four compounds reveals that substituents of R-isophthalic acids have profound influence on regulating or constructing of the cocrystal materials.In ChapterⅢ, four novel silver（Ⅰ） mixed-ligand coordination polymers, have been pre-pared by the assembly of 4-bpt, Ag（Ⅰ） with H2ip, and its 5-substituted derivatives, H3hip, H4aip and H2nip, respectively, under the similar solvothermal conditions. {[Ag3（4-bpt）2]·（Hip）·（ip）·（H2O）6}n （5）, {[Ag3（4-bpt）2]·（H2hip）·（Hhip）·（H2O）4}n （6） and{[Ag3（4-bpt）2]·（H3aip）·（H2aip）·（H2O）4}n （7） have similar 3-D hydrogen bonded su-pramolecular architectures. In which, all of these 2-D coordination polymeric layers are ar- ranged with alternate 38-, 14- and 6-membered subrings nevertheless possess different ring sizes due to the presence of substituent groups （-NH2, -OH） in 6 and 7 and their discrepancy of electron-donating capability. Interestingly, the bringing of -NO2 on isophthalic acid in polymer [Ag（4-bpt）（Hnip）]n （8） results in a different neutral 1-D coordination polymeric chain, and finally produces an unusual 3-D interdigitated tactic motif. These results indicate that the nature of substituent groups plays a key role on influencing the structures of coordi-nation polymers.In ChapterⅣ, self-assembly of various isomers of bpt ligands （2-bpt, 3-bpt and 4-bpt） and H3sip with different metal salts affords twelve new mixed-ligand coordination com-plexes, namely [Cd（2-bpt）2（H2sip）2] （9）, {[Cd（H-3-bpt）2（H2O）2]·（Hsip）2·（H2O）2}n （10）,[Cd（4-bpt）（Hsip）（H2O）4]·（H2O）1.5 （11）, [Cu（2-bpt）2（H2O）2]·（H2sip）2·（H2O）6 （12）, {[Cu（3-bptXHsip）（H2O）3]（H2O）2.5}n （13）, {[Cu（4-bpt）（H2O）4]·（Hsip）·（H2O）3}n （14）, [Zn（3-bpt）2（H2O）4]·（H2sip）2·（H2O）6 （15）, [Co（3-bpt）2（H2O）4]·（H2sip）2·（H2O）6 （16）, [Zn（2-bpt）2（Hsip）]·（H2O）3 （17）,[Co（2-bpt）2（H2O）2]·（H2sip）2·（H2O）3（18）,[Ni（2-bpt）2（H2O）2]·（H2sip）2·（H2O）6 （19） and [Ag2（2-bpt）2]·（H2sip）2·（H2O）0.5 （20）, which ex-hibit significant structural diversification, and thus reveal that product diversity of such com-plexes can be well regulated by the nature of the isomers of bpt ligands as well as the metal ions. Additionally, for all crystalline complexes, hydrogen bonding and aromatic interactions also play the directing role in the construction of higher-dimensional networks.In ChapterⅤ, four mononuclear complexes [ZnL2（H2O）4]（H2O）8 （21）,[CdL2（H2O）4]·（H2O）2 （22）,[ZnL2（H2O）4]·（H3hip）2·（H2O）0.5（23）and[CdL2（H2O）4]·（H3hip）2·H2O （24） have been successfully synthesized by the reaction of zinc（Ⅱ）/cadmium（Ⅱ） salt and a new prepared ligand HL with malonic/H3hip acid. The dif-ferent nature of ZnⅡand CdⅡions leads to the discrepancies about configuration and confor-mation of L-, which proves that HL is a quite flexible ligand with adjustable backbone to meet the requirement of structural assembly. And also, by comparing these structures with other related complexes of L-, we can conclude that this ligand may display rich coordina-tion fashions upon different metalation interactions. |
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