Synthesis, crystal structure of poly[3,3-dimethyl-1,1-(ethane-1,2-diyl)diimidazolium[tetra--bromido-silver(I)]]

Department of Chemistry and Chemical Engineering, Mianyang Normal University, Mianyang 621000,

China

E-mail : wangzhiguo224865@163.com

Manuscript received online 28 March 2014, revised 29 April 2014, accepted 14 May 2014

The title complex [[(CH₃ {CH(NCHCHN)}CH₂ ]₂ ]_n ²⁺[(Ag₂Br₄ )^2–]_n has been synthesized by the reaction of Ag₂O with [[(CH₃ {CH(NCHCHN)}CH₂ ]₂ ]²⁺ Br₂^– in a 1 : 3 molar ratio at 189 ºC in DMSO and characterized by elemental analysis, ¹H NMR and single-crystal X-ray diffraction analysis. It crystallizes in monoclinic, space group P21/c with a = 9.1402 (10) Å, b = 12.5548 (13) Å, c = 8.2710 (9) Å, β = 104.696 (2)º, V = 918.07 (17) ų , M_r = 363.82, Z = 4, D_c = 2.632 g/cm³ , µ(MoKα) = 10.83 mm^–1 and F(000) = 676. The structure was refined to R = 0.028 and wR = 0.071 for 1466 observed reflections with I > 2σ (I). The asymmetric unit of the title salt, [[(CH₃ {CH(NCHCHN)}CH₂ ]₂ ]_n ²⁺[(Ag₂Br₄ )^2–]_n , contains one-half of a substituted imidazolium cation, one Ag⁺ and two Br– ions. The cation is completed by crystallographic inversion symmetry. The crystal structure is made up from polymeric sheets of {[AgBr₂ ]^–}_n anions. The basic building unit of the anion is a slightly distorted AgBr₄ tetrahedron. A fourand twelve-membered ring system is formed by corner sharing of the AgBr₄ tetrahedra. The imidazolium cations are located between the anionic sheets and partly protrude into the voids defined by the twelve-membered rings.