title: Copper(I) and silver(I) 2-methylimidazolates: extended isomerism, isomerization, and host-guest properties.
abstract: Syntheses, structures, and properties of univalent coinage metal 2-methylimidazolate supramolecular isomers [M(mim)] (1, M = Cu; 2, M = Ag) were investigated in detail. In addition to the known isomers, namely, zigzag chains [Cu(mim)] (1a) and [Ag(mim)] (2a), molecular octagon [Cu(8)(mim)(8)]·C(6)H(6) (1b), decagon [Cu(10)(mim)(10)]·C(8)H(10) (1c), helical chain [Ag(4)(mim)(4)]·C(6)H(6) (2b), and S-shaped chain [Ag(4)(mim)(4)]·C(8)H(10) (2c), two new structures including a polyrotaxane [Cu(10)(mim)(10)]·[Cu(mim)] (1d, C2/m, a = 14.452(4) Å, b = 27.712(7) Å, c = 11.427(3) Å, β = 125.899(4)°, V = 3707(2) Å(3)) and a new octagon [Ag(8)(mim)(8)]·Me(2)CO (2d, C2/c, a = 21.852(3) Å, b = 12.101(2) Å, c = 20.907(3) Å, β = 90.875(2)°, V = 5528(2) Å(3)) were discovered. The potential porous properties of guest-containing [M(mim)] isomers were studied by thermogravimetry, X-ray powder diffraction, vacuum thermal desorption, and CO(2) sorption experiments. The isomers show distinctly different guest removal behaviors depending on their pore structures. By heating, the guest-containing isomers, 1b-1c and 2b-2d, undergo irreversible, two-step, crystal-to-crystal structural transformations to form the guest-free isomers 1a or 2a, respectively. Except 1b, other guest-containing isomers can retain their porous structures after removal of the template molecules, which were confirmed by CO(2) sorption experiments.
authors.affiliation: MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, KLGHEI of Environment and Energy Chemistry, School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
authors.forename: Chun-Ting
authors.initials: CT
authors.lastname: He
authors.forename: Yi-Jiang
authors.initials: YJ
authors.lastname: Liu
authors.forename: Tian-Qi
authors.initials: TQ
authors.lastname: Zhao
authors.forename: Xiao-Min
authors.initials: XM
authors.lastname: Lu
authors.forename: Wei-Xiong
authors.initials: WX
authors.lastname: Zhang
authors.forename: Jie-Peng
authors.initials: JP
authors.lastname: Zhang
authors.forename: Xiao-Ming
authors.initials: XM
authors.lastname: Chen