Ⅰ.Synthesis, Structure And Metal Complexation Studies Of Ortho-Linked Oxacalix[n] Arene[n] Hetarenes Ⅱ.Synthesis And Structure Of 1, 3, 5-Tris(Bromomethy)-2, 4, 6-triethyl-benzene Derivatives

Supramolecular chemistry is a new research field with rapid development and vitality. Currently, it has drawn extensive research attention from material scientists, crystallogrophers, chemists, biologists and other scientists of all disciplines. The design and synthesis of 'host' molecules is the main focus in the area of 'host-guest' chemistry. The 'host' molecules of current focus is limited on a few kinds of compounds, and consequently restricts the development of this research field. In order to achieve complexing (capturing) a specific 'guest' molecule (ion), designing and synthesizing the new types of 'host' molecules with unique structures to recognize specific 'guest' molecule (ion) is necessary. In this paper, we present the design and synthesis of several categories of 'O' bridged asymmetric 'calixarene', their solid-state structures have been determined by single crystal X-ray diffraction. The ability of these nitrogen containing oxocalixarene to complex metal ions have been explored.1. By the analysis structural conformation of the known hetero-atom bridged calixarenes, we designed several '0' bridged asymmetric 'calixarene' series, and investigated the synthetic conditions (including the use of microwave chemistry) and thermal stabilities of these compounds.2. By employing diphenols and aza aromatic ring with two substitutions (or triazine) as precursor, we have synthesized nine asymmetric nitrogen containing oxocalixarenes, eight of which have not been reported. Their structures have confirmed by ¹H-NMR, ¹³C-NMR, HRMS, and XRD. Through the structure analysis, we found that some of the structural isomers adopted completely different conformations in the solid state. For example, orthto-bridged oxocalix[3]arene[3] pyrazine adopts an 1,3,5-alternate conformation, however, ortho-bridged oxocalix[3] arene[3]pyrimidine adopts a core conformation with C₃ symmetry. While asymmetric para and meta-bndged oxocalix[2]arene[2]pyrazine adopts a 'butterfly' conformation. 3. Preliminary studies on the possibility of 'supramolecular structure' formations by these asymmetric nitrogen containing 'oxocalixarenes' have been carried out. Ortho-linked oxocalix[2]arene[2]pyrazine was found to form a 'gap'-like compounds by complexing two silver ions. Further studies on molecular recognition by these "supramolecules" is currently going on in this laboratory. 1,3,5-Tris(bromomethyl)-2,4,6-triethylbenzene and its derivatives, a class of molecules with unique space configuration, they have shown important roles and significances in supramolecular chemistry, such as, self-assembly, catalyst carrier, metal organic complexes, macrocyclic compounds. Currently, the employment of 1,3,5-tris(methylene)-2,4,6-triethylbenzene derivatives for synthesizing new 'cage'-like compounds has drawn considerable attentions from material scientists and other disciplines. The design and synthesis of new 1,3,5-tris(methylene)-2,4,6-triethyl-benzene derivatives with special functionalities and unique structural conformations is essential and these 'supramolecules' have high potential in the future development of functional materials. In this paper, we focused on the following aspects with 1,3,5 -tris(bromomethyl)-2,4,6-triethylbenzene as starting material.1. By employing l,3,5-tris(bromomethyl)-2,4,6-triethylbenzene and substituted phenol, anilines as reaction precursors, we have synthesized 20 compounds with l,3,5-tris(methylene)-2,4,6-triethylbenzene scaffold, 17 of them have not been reported in the literature.2. Eight compounds (five of them are new compounds) have been synthesized by the reactions of 1,3,5-Tris(bromomethyl)-2,4,6-triethylbenzene and malonate derivatives, imidazole. In these compounds, the substituting groups have a great influence on their chemical stabilities. For example: hexaethyl 2,2',2"-(2,4,6-triethylbenzene-1,3,5-triyl)- tris(methylene)trimalonate could be hydrolyzed by potassium hydroxide to generate 2,2',2" -(2, 4, 6- triethylbenzene-1, 3, 5 - triyl) tris (methylene)trimalonic acid. However, hexaethyl 2,2',2"-(1,1',1"-( 2,4,6-triethyl-benzene-1,3,5-triyl)tris(propane-1,1-diyl)) trimalonate was hardly to be hydrolyzed in even hash condition.3. The structures of the new compounds have been confirmed by ¹H-NMR, ¹³C-NMR, and some also by HRMS and XRD.