title: Synthesis and stereochemistry of long-chain quinoxaline metallocyclophanes.
abstract: Condensation of 1,2-diamino-4,5-bis(n-alkoxy)arenes with an oligopyridyl-type alpha-diketone afforded a series of long-chain pyridine-quinoxaline hybrids. These were evaluated for their ability to self-assemble with tetrahedral Cu(I) and Ag(I) to form dimeric, double-decker amphiphillic complexes having a flattened metallocyclophane topology. Detailed NOESY and T1 relaxation time experimentation showed that the configuration of the dicopper(I) complexes corresponds to inversion (meso) symmetry, which leads to an extended molecular shape, wherein the alkoxy chains of the individual ligand components lie on opposite sides of the metallocyclophane core, as opposed to the same side. Preliminary measurements show that the disilver(I) complexes having nC12H25 and nC18H37 chains exhibit reversible melting processes and undergo two endothermic transitions each, at 189/237 and 59/80 degrees C, respectively.
authors.affiliation: Chemical Laboratory, University of Kent, Canterbury, Kent, UK CT2 7NH.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Howard
authors.forename: Fenton R
authors.initials: FR
authors.lastname: Heirtzler
authors.forename: Sandra I G
authors.initials: SI
authors.lastname: Dias
mesh_terms: D003300:Copper / Q000737:chemistry*; D004988:Ethers, Cyclic / Q000737:chemistry*; D006571:Heterocyclic Compounds / Q000138:chemical synthesis / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy / Q000379:methods / Q000592:standards; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D044367:Phase Transition; D011810:Quinoxalines / Q000737:chemistry*; D012015:Reference Standards; D012834:Silver / Q000737:chemistry*; D013237:Stereoisomerism; D013696:Temperature
chemical_list: D004988:Ethers, Cyclic; D006571:Heterocyclic Compounds; D009942:Organometallic Compounds; D011810:Quinoxalines; D012834:Silver; D003300:Copper