title: Alkane lengths determine encapsulation rates and equilibria.
abstract: A cylindrical capsule provides an environment for straight-chain alkanes that can properly fill the space through extended or compressed conformations. The encapsulation rates of a series of alkanes were examined and found to be dependent on guest length: the rates of uptake are C(9) > C(10) > C(11), while complex stability is in the reverse order, C(11) > C(10) > C(9). Direct competition experiments, pairwise or between all 3 alkanes, maintain this order as the longer alkanes sequentially displace the shorter ones. The distribution of species with time provides a clock for this complex system, which combines elements of self-sorting phenomena and dynamic combinatorial chemistry. The clock can be stopped by replacing the alkanes with the superior guest 4,4'-dimethylazobenzene, then restarted by irradiation.
authors.affiliation: Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States.
authors.forename: Wei
authors.initials: W
authors.lastname: Jiang
authors.forename: Dariush
authors.initials: D
authors.lastname: Ajami
authors.forename: Julius
authors.initials: J
authors.lastname: Rebek
mesh_terms: D000473:Alkanes / Q000737:chemistry*; D002214:Capsules; D019281:Dimerization; D004988:Ethers, Cyclic / Q000737:chemistry; D007700:Kinetics; D008958:Models, Molecular; D008968:Molecular Conformation; D012118:Resorcinols / Q000737:chemistry; D013816:Thermodynamics
chemical_list: D000473:Alkanes; D002214:Capsules; D004988:Ethers, Cyclic; D012118:Resorcinols; C442939:cavitand