The reaction of 5-methyl-2-mercaptobenzimidazole (5MBI) with silver ions in organic solvents form widely varying macrostructured or polymeric structures, depending on the anion type. In the case of carboxylate anions, the reaction of 5MBI with [Ag(O2CxH2x-1]2 results in high yields of hexameric clusters containing bridging 5MBI units, [Ag·5MBI·]6, the details of which are reported here. The six silver atoms of [Ag·5MBI]6 are arranged as a trigonal antiprism with each 5MBI bonded to three silver atoms, two bridged with the sulfur and the third bridged with the nitrogen. From these results, and comparison to the reaction of AgBr that forms a polymeric [AgBr·MBI(acetone)0.5]4 complex, a mixture of different complexes may be expected to form in a photo-thermographic imaging construction.
Richard Swatloski, Robin Rogers, D. Whitcomb, "Mode of Complex Formation Between Thiones and Silver Ion Within a Photothermographic Formulation: The Crystal and Molecular Structure of Hexa- (silver-5-methyl-2-mercaptobenzimidazole THF)" in Journal of Imaging Science and Technology, 2007, pp 547 - 551, https://doi.org/10.2352/J.ImagingSci.Technol.(2007)51:6(547)