Main Group Metal Halide Complexes with Sterically Hindered Thioureas XIV. A Reinvestigation of Coordination Sensitive Modes in the Solid State Vibrational Spectrum of 1,3-Dimethyl-2(3H)-imidazolethione and Related Compounds


Chemistry and Biochemistry

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The assignment of the C-S stretch in the IR spectrum for 1,3-dimethyl-2(3H)-imidazolethione (dmit) reported in an earlier paper was restudied in light of new compds. reported and an x-ray structure of 1,3-dimethyl-2-(S-methylthio)-2(3H)-imidazoylium iodide (tmii). Conflicting literature values and assignments were also studied. For dmit, the C-S stretch was found in the 1170-1180 cm-1 region, and 3 of the 4 thioamide peaks reported by other researchers as coordination sensitive modes for thiourea-type compds. did not have significant C-S contribution based on the compds. studied . Crystallog. data for tmii: C6H11N2SI, M = 207.04, space group P21/n, Z = 4, λ(Mo Kα) = 0.71073 Å, μ(Mo Kα) = 3.13 mm-1, dc = 1.699 g/cm3, Do = 1.66 g/cm3, a 7.846(2), b 11.754(2), c 12.578(2) Å, β 95.51(2)°, R = 0.034, Rw = 0.042. Addnl., a new sterically hindered thiourea, 1-Me-3-(2-propenyl)-2(3H)-imidazolethione (mpit), and a new complex, ZnCl2(mpit)2, are reported and characterized.