Synthesis And Complexing Properties Of Cyclotriveratrylene Functionalized Derivatives

During the past decades, much attention have been gained to calixarenes, which are known as the third generation of supramolecular compounds after cyclodextrins and crown, as a result of their ease of chemical modification, high chemical stability, and the adjustable cavity size. Cyclotriveratrylene (CTV), another kind of macrocyclic compounds with similar structures to the calixarenes, displays more and more potential applications in supramolecular chemistry and nano materials, because of its unique C3symmetrical structure and rich electronic cavity. A series of functional cyclotriveratrylene derivatives were successfully synthesized mainly based on the modification of phenolic hydroxyl groups in the cyclotriveratrylene, with the aim of enhance the rich electronic of cavity and the metal complexing ability. Thus the functionalized cyclotriveratrylenes have played versatile applications in the fields of self-assembly, molecular recognition, ion sensors and metal complexing catalysis. In this work, we have investigated the synthesis of functionalized cyclotriveratrylene (CTV) derivatives with using guaiacol or catechol as the precursors. A series of cyclotriveratrylene derivatives such as imidazolium salts, amides, Schiff bases were prepared and characterized with spectroscopic methods. The coordination properties of cyclotriveratrylene derivatives to transition metals are also examined.1. Guaiacol and catechol were firstly alkylated with dihalides to give Guaiacol and catechol derivatives with three or six chloroalkoxyl groups, respectively. Then the BF3·Et2O catalyzed condensation of Guaiacol and catechol derivatives with paraformaldehyde to give the chloroalkylated cyclotriveratrylenes. Thirdly the reaction of the chloroalkylated cyclotriveratrylene derivatives with N-methylimidazole, N-butylimidazole and N-benzylbenzimidaole successfully resulted in the corresponding cyclotriveratrylene imidazolium salts. Their structures were fully characterized by different kinds of spectroscopic methods.2. A series of cyclotriveratrylene functionalized amide derivatives were successfully synthesized by using two kinds of synthetic methods. In the first method the ammonolysis of the previously cyclotriveratrylene oxyacetates with different amines in refluxing ethanol directly afforded the corresponding cyclotriveratrylene functionalized amide derivatives.In the second method, guaiacol was alkylated with N, N-dialkyl chloroacetoamides to give guaiacol amides, which in turn cyclocondensated with paraforaldehyde in the presence of BF3-Et2O to give the desired cyclotriveratrylene amide derivatives in moderate yields. The structures of cyclotriveratrylene amide derivatives were characterized with by NMR, IR spectra and were further confirmed by X-ray diffraction determination of one single-crystal structure.3. By using similar synthetic procedure as above, guaiacol was firstly alkylated with chloroalkoxyl substituted aromatic aldehydes to give the guaiacol aldehydes. Then through the cyclocondensation of guaiacol aldehydes with paraformaldehyde, the cyclotriveratrylene derivatives with aldehyde groups were obtained. Afterwards the various cyclotriveratrylene Schiff bases could be easily prepared by the condensation of aldehydes with corresponding acyl hydrazides, acylamides and other nitrogen-containing compounds.