Novel macrocyclic compounds as building blocks in supramolecular chemistry

Title from PDF of title page (University of Missouri--Columbia, viewed on October 25, 2010).The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file.Dissertation advisor: Dr. Jerry L. Atwood.Vita.Ph. D. University of Missouri--Columbia 2010.Resorcinarenes and pyrogallolarenes have been widely used as building blocks for novel synthetic receptors and supramolecular self-assemblies. To explore new chemistry of these compounds, new substituted macrocyclic arenes were synthesized. Introduction of functionalities such as nitro, cyano, and amido groups into the resorcin[4]arene molecule can significantly change the chemical properties of these macrocycles. The spectroscopic data and X-ray crystal structures of the new tetracyano resorcin[4]arenes show that these compounds adopt a crown conformation and that all alkyl substituents are in the axial position. No hydrogen-bonded self-assembly is observed suggesting that the presence of a cyano group inhibits the formation of the hydrogen bonds between the macrocycles. The complex of silver(I) ion and tetracyano resorcin[4]arene is a three dimensional polymer in which the silver center is coordinated by three cyano groups of the macrocycle and possesses an unusual trigonal planar geometry. No new tetranitro and tetraamido resorcin[4]arenes were synthesized under the studied conditions.Includes bibliographical reference

Organocatalytic Ring-Opening Polymerization of ε-Caprolactone Using bis(N-(N′-butylimidazolium)alkane Dicationic Ionic Liquids as the Metal-Free Catalysts: Polymer Synthesis, Kinetics and DFT Mechanistic Study

In this work, we successfully synthesized high thermal stable 1,n-bis(N-(N′-butylimidazolium)alkane bishexafluorophosphates (1,n-bis[Bim][PF6], n = 4, 6, 8, and 10) catalysts in 55–70% yields from imidazole which were applied as non-toxic DILs catalysts with 1-butanol as initiator for the bulk ROP of ε-caprolactone (CL) in the varied ratio of CL/nBuOH/1,4-bis[Bim][PF6] from 200/1.0/0.25–4.0 to 700/1.0/0.25–4.0 by mol%. The result found that the optimal ratio of CL/nBuOH/1,4-bis[Bim][PF6] 400/1.0/0.5 mol% at 120 °C for 72 h led to the polymerization conversions higher than 95%, with the molecular weight (Mw) of PCL 20,130 g mol−1 (Đ~1.80). The polymerization rate of CL increased with the decreasing linker chain length of ionic liquids. Moreover, the mechanistic study was investigated by DFT using B3LYP (6–31G(d,p)) as basis set. The most plausible mechanism included the stepwise and coordination insertion in which the alkoxide insertion step is the rate-determining step