Crystal structure of 2-bromo-3-dimethylamino-N,N,N′,N′,4-pentamethyl-4-(trimethylsilyloxy)pent-2-eneamidinium bromide

Abstract

The reaction of the orthoamide 1,1,1-tris(dimethylamino)-4-methyl-4-(trimethylsilyloxy)pent-2-yne with bromine in benzene, yields the title salt, C15H33BrN3OSi+·Br−. The C—N bond lengths in the amidinium unit are 1.319 (6) and 1.333 (6) Å, indicating double-bond character, pointing towards charge delocalization within the NCN plane. The C—Br bond length of 1.926 (5) Å is characteristic for a C—Br single bond. Additionally, there is a bromine–bromine interaction [3.229 (3) Å] present involving the anion and cation. In the crystal, weak C—H...Br interactions between the methyl H atoms of the cation and the bromide ions are present.