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

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+) Br-2(-) in a 1 : 3 molar ratio at 189 degrees C in HMSO and characterized by elemental analysis, H-1 NMR and single-crystal X-ray diffraction analysis. It crystallizes in monoclinic, space group P21/c with a = 9.1402 (10) angstrom, b = 12.5548 (13) angstrom, c = 8.2710 (9) angstrom, beta = 104.696 (2)degrees, V = 918.07 (17) angstrom(3), M-r = 363.82, Z = 4, D-c = 2.632 g/cm(3), mu(MoK alpha) = 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 > 2 sigma (1). 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 AgRr(4) tetrahedron. A four- and 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.