| Calix[4]arenes are cyclic tetramers made up of phenol and methylene units. In an effort of synthesizing self-assembling molecular capsules and possible complexes based on two cone calix[4]arenes, a strategy was sought that would enable bridging the phenolic oxygens and rigidifying the cone calixarene.;Reaction of calix[4]arene with 1,3-dibromopropane using NaH in DMF resulted in an elimination product, tetrakis(allyloxy)calixarene. Another attempt, performed by the reaction with 1,3-dibromopropane using K2CO 3 in CH3CN, gave a bis(bromopropoxy)calixarene in good yield. When the ratios of the reagents were varied, several new compounds were obtained: a biscalixarene, tetrakis(3-bromopropoxy)calixarene with a partial cone conformation, and a 1,3-bis(3-bromopropoxy)calixarene with a flattened cone conformation in which two of the distal phenolic oxygens are bridged by a -(CH2) 3- group. On the other hand, treatment of tert-butylcalix[4]arene with 1,5-dibromopentane using K2CO3 in CH3CN gave a new half-bridged calixarene as the major product. The compound was identified as a lower rim substituted calixarene with a cone conformation in which two of the proximal phenolic oxygens are bridged by a -(CH2 )5- group and one of the other phenolic oxygens is attached to a bromopentyl group. This compound is a potential intermediate for the preparation of doubly-bridged calixarenes. In another attempt to prepare calixarenes with small bridges using ring-closing olefin metathesis, a novel bis-calix[4]arene was isolated.;The structural assignments and conformations of the new calixarenes were established using MALDI-TOF MS, a combination of 1D and 2D NMR spectral techniques (1H NMR, 13C NMR, DEPT-135, COSY, HMQC, HETCOR, NOESY and HMBC), and X-ray crystallography.;In another project of conducting polymers, poly(3-hexylthiophene) (P3HT) and copolymers containing P3HT have been synthesized. Poly(3-hexylthiophene) has attracted great interest both from synthetic considerations as well as from the potential applications due to the good electrical conductivity, environmental stability, and other interesting properties. Regioregular poly(3-hexylthiophene) was prepared using the Grignard metathesis polymerization method. This homopolymer was integrated to the block polymer polystyrene using atom transfer radical polymerization to form copolymer poly(3-hexylthiophene)-b-polystyrene. An experiment was also conducted to synthesize the di-block copolymer poly(3-hexylthiophene)- b-poly(2-vinylnaphtalene) using same method. Gel permeation chromatography (GPC) analysis showed an increase in the polydispersity index. |
