The molecular structure of [bis-(2-tribromomethylsulfonyl-benzothiazole)-silver(I)-tetrafluoroborate.(acetone)] [Ag{(C7H4NS)SO2CBr3}2BF4.Me2CO] : A possible model for bromine elimination of silver halide fog centers

The crystal and molecular structure of [bis-(2-tribromomethylsulfonyl-benzothiazole)-silver(I)-tetrafluoro- borate.(acetone)] solvate, [Ag{(c 7 H 4 NS)SO 2 CBr 3 } 2 BF 4 .Me 2 cO], has been determined by single crystal x-ray analysis. The space group is P2 1 /c, a = 16.985(5) A, b = 10.426(3) A, c = 19.693(4) A, β = 111.78(2)°, V = 3238 A 3 . Chelation by the 2-tribromomethylsulfonyl) benzothiazole ligand occurs through the ring nitrogen and sulfone oxygen, resulting in a distorted tetrahedral configuration around the silver atom. This complex is proposed as part of an alternative model for fog center removal in silver halide photographic constructions, in contrast to the theory of bromine radical formation from tribromomethyl compounds. Compounds containing tribromomethyl groups, which also possess sites capable of coordinating with a silver halide surface, may act as ligands to position the bromine on the silver halide surface. This placement of the bromine near the fog centers is suggested as a route to enhance the efficiency of this class of compounds as antifoggants.