Construction Of Asymmetric Homotriazine Conjugates And Their Catalytic Properties

Unsmmertrical triazine conjugates are attracting increasing attention in materials science, due to their unique?-electronstructure and optical properties. However, there are some drawbacks in systhesis unsmmertrical triazine conjugates, such asweak compatibility, poor regioselectivity and limition to the side chain structure. Herein, alknal-triazines and triazine triazole conjugates were successfully prepared by the Pd-catalyzed Sonogashira reaction and Cu-catalyzed click reaction, respectively. The photo-physical and single crystal experiments of unsmmertriacl triazine conjugates have been determined. Furthermore,we studied the catalytic activity of triazine triazole (TT) conjugates in copper-catalyzed Sonogashira reaction, given its properties ofmultiply hard donor sites and diverse coordination modes. The main contents are included as follows:(1) A concise route for the synthesis of linear and V-shaped alkynyl-1,3,5-triazines had been developed by starting from 2,4-dichloro-1,3,5-triazine derivatives. The sequential substitution of the 2- and 4-chloro groups by a regioselective Sonogashira coupling reaction afforded symmetric and unsymmetric V-shaped alkynyl-1,3,5-triazines. Pd/1,10-phenanthroline catalyst system showed good compatibility with the -OCH3,-NPh2, and p-CH3OC6H4- substitutents and furnished the targeted linear alkynyl-1,3,5-triazines in 69%-94% yields. A Pd/Ag bimetallic system afforded the desired symmetric and unsymmetric V-shaped alkynyl-1,3,5-triazines in 75%-85% yields. The photophysical properties of the new alkynyl-1,3,5-triazine conjugates were characterized experimentally. The X-ray diffraction analysis of 2a confirmed a coplanar position between the phenyl group and the 1,3,5-triazinal moiety. Intermolecular ?-? interactions were observed between two of the TZ units, and the shortest atomic contact distance between the phenyl moietiesof two adjacent molecules was 3.655 A.(2) A series of unsymmetrical triazine triazole conjugates wereprepared by the copper-catalyzed cycloaddition reactions of 2-azide-4,6-dimethoxy-1,3,5-triazine with terminal alkynes under mild reaction conditions.10 examples were sythzed with the yield of 65%-91%. X-ray experiment demonstrated that the donor triazole and acceptor triazinal (TZ) units are coplanar. Futhermore, photophysical properties of these TT compounds have been determined.(3) Triazine Triazole conjugates (TT) were developed as efficient ligands for CuSO4·5H2O catalyzed Sonogashira and decarboxylativecross-coupling reaction.Cu(I) and Cu(?) salts were accelerated by TT ligands for the cross-coupling reactions.The ligand effect of TT ligandsindicated that the electron-donating groups on heterocyclicring were unfavorable for catalytic efficiency of the corresponding TT ligands. The combination of CuSO4·5H2O/TT as an economic and efficient system, catalyzed 20 examples with the yields of 61%-99% in Sonogashira reaction. In addition, this new protocol showed good compatibility in decarboxylativecross-coupling reaction, and afforded 61%-95% yields.