Short communication. Structural studies of bromine adducts of 1,2‐ and 1,4‐bis(phenylseleno)benzenes. Evidence for the (TB, MC) structure of 1,2‐(PhSeBr₂)₂C₆H₄

Abstract

1,2‐Bis(phenylseleno)benzene reacted with equimolar amount of bromine to yield a trigonal bipyramidal (TB) adduct, in contrast to the molecular complex (MC) structure of selenanthrene with bromine. Whereas the structure of 1,4‐(PhSeBr2)2C6H4 was (TB, TB) at the two selenium atoms, that of the 1,2‐derivative was demonstrated to be (TB, MC), the first example of an MC structure of PhSeC6H4Y with Br2 [Y = 2‐PhBr2Se(TB)]. Both electronic and steric effects of the group must play an important role in MC formation. Rapid structural exchange in this tetrabromide, (TB, MC) ⇄ (MC, TB), was also observed.

Structural studies on diaryl selenide dihalides in solution: molecular complex formation of substituted diphenyl selenides with bromine

“…Substituted diphenyl selenides (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17), bearing various substituents at the 2-, 3-and/or 4-positions of 1, are prepared, 6 together with their chlorine, bromine and iodine adducts. The 1 H and 13 C NMR chemical shifts (δ(H) and δ(C), respectively) have been measured.…”

“…The structure of 2ؒ2Br 2 is TB for one of the SeBr 2 moieties and the other is MC, which is notated as (TB, MC). 11, 12 Since 2ؒBr 2 is a 2-phenyl(dibromo)selanyl derivative of 1, it is recognized that a derivative of 1 reacts with bromine to give MC. The (TB, MC) formation of 2ؒ2Br 2 led us to the following working hypothesis: such substituted diphenyl selenides can be prepared 9 that yield MC with bromine if 1 is suitably modulated electronically 13 and/or sterically.…”