Driving the Assembling of Zirconium Tetraoxalate Metallotectons and Benzimidazolium Cations: From Three Dimensional Hydrogen-Bonded Compact Architectures to Open-Frameworks

作者：Mouchaham Georges; Roques Nans^*; Imaz Inhar; Duhayon Carine; Sutter Jean Pascal

来源：Crystal Growth & Design, 2010, 10(11): 4906-4919.

DOI：10.1021/cg1009785

Charge-assisted H-bond associations between [Zr(C2O4)(4)](4-) preformed anionic complexes and several ditopic monocations based on the benzimidazolium motif ([H-2-Bim](4) cations) have been envisioned for the tentative elaboration of 3D H-bonded and open-framework architectures. Reactions involving [Zr(C2O4)(4)](4-) units and [H-2-Bim](1) cations in (a) a charge stoichiometric amount, (b) a defect, and (c) an excess of cation afforded three different compounds of formula {(H-2-Bim)(4)[Zr(C2O4)(4)]}center dot H2O (1), {K(H2O)(H-2-Bim)(3)[Zr(C2O4)(4)]}center dot 2H(2)O (2), and {(H-2-Bim)(4)[Zr(C2O4)(4)]} (3), respectively. Structural analyses revealed marked differences in their formulations and in their supramolecular connectivities. These results traduce the importance of cation concentration on the association schemes. Among them, compound 3 exhibits a chiral structure analyzed as resulting from the interpenetration of two 3D H-bonded homochiral and independent networks. To avoid this interpenetration and to study the influence of the cation substitution for fixed experimental parameters, 2-amino and 2-methyl substituted [H-2-Bim](4) cations ([H-2-2-NH(2)Bim](4) and [H-2-2-NH(2)Bim](4), respectively) have been envisioned as cationic building-blocks. Structure analysis for the corresponding materials ({(H-2-2-NH(2)Bim)(4)[Zr(C2O4)(4)]} (4) and {(H-2-2-MeBim)(4)- [Zr(C2O4)(4)]}center dot 7H(2)O (5), respectively) revealed that the amino group contributes in the H-bonded framework, whereas the methyl impairs the formation of H-bonds between the cations and the anions. These observations contribute to explain the marked structural differences between 3 and these two networks. With 5-methyl- and 5-chlorobenzimidazolium cations ([H-2-5-MeBim](4) and [H-2-5-ClBim](4), respectively), [Zr(C2O4)(4)](4-) is converted into its binuclear version, [Zr-2(C2O4)(7)](6-), yielding {(H-2-5-MeBim)(6)[Zr-2(C2O4)(7)]}center dot 3H(2)O (6) with a close-packed 3D-network and {(H-2-5-ClBim)(6)[Zr-2(C2O4)(7)]}center dot 13.5H(2)O (7) with an open-framework architecture (potential solvent accessible void volume of 23%). For 7, Cl center dot center dot center dot pi interactions contribute to the cohesion of the 3D supramolecular architecture.

• 出版日期2010-11