Synthesis and Conformational Studies on [3.3.3]Metacyclophane Oligoketone Derivatives, and Their Metal Ion Recognition

Abstract

Chemical reactions were used to synthesize 2,11,20-tris(ethanedithia)-9,18,27-trimethoxy-6,15, 24-tri-tert-butyl[3.3.3]metacyclophane 2 and 2,11-bis(ethanedithia)-9,18,27-trimethoxy-6,15,24tri-tert-butyl[3.3.3]metacyclophane 4 from 6,15,24-tri-tert-butyl-9,18,27-trimethoxy[3.3.3]metacyclophane-2,11,20-trione 1 and-2,11-dione 3. The yields of 2 and 4 were 70% and 81% respectively. The conformations of the synthesized compounds 2 and 4 were studied using mainly solution Proton Nuclear Magnetic Resonance (1 H NMR) spectroscopic methods. Compounds 2 and 4 were found to have a partial-cone conformation. Detailed variable temperature Proton Nuclear Magnetic Resonance studies further confirmed the partial-cone conformation for the two products, 2, 4. During the variable temperature nuclear magnetic resonance spectroscopic studies, compound 2 was found to have a coalescence temperature of about 0˚C. Extraction of silver ions with compound 2 gave an extractability of 82% while the parent compound 1 showed zero (0) silver affinity. A 1:1 mol/mol mixture of compound 2 and silver ions studied by solution 1 H NMR revealed a novel "Molecular Roulette" type of motion.

Synthesis and Crystal Structure Determination of 4’,9’,4”,9”-Tetra-<i>t</i>-Butyl- 1’,6’,1”,6”-Tetramethoxy-2,5-Dithia[3.3] Metabiphenylophane

“…On the other hand, selected bond lengths (Å) and bond angles (˚) for the minor isomer were also listed in Table 3. Notably, the two sulfurbridge ether chains on the [3.3] metacyclophane ring are pseudo-boat conformation [16]- [18].…”

Synthesis and Structure of 1,2‐Dimethylene[2.10]metacyclophane and Its Conversion into Chiral [10]Benzenometacyclophanes

“…Metacyclophanes (MCPs) have been known for nearly 45 years, with the short chain ( n = 4–6) members having attracted the appreciation of chemists as exemplary compounds to test the limits of bending aromatic rings . Some of the reports focus on synthesis and conformational studies of the macrocyclic compounds, but few researchers have investigated the flexible conformations of the synthesized macrocyclic compounds and their conversion into rigid structures to provide suitable platforms for diverse complexation experiments . Our interest in this field stems from investigations of cyclic diynes in which two double bonds were part of the ring system …”