The title compound,6, a novel 1:1 complex of 1-chloro-1,2-benziodoxolin-3(1H)-one (5) andtetra-n-butylammonium chloride, was prepared from tetra-n-butylammoniumo-iodoxybenzoate (7) and acetyl chloride. A single crystal of6 was subjected to X-ray analysis: triclinic, space group
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a=10.239(2),b=11.518(2),c=11.523(3)Å; a=73.20(2); ß=87.85(2), ?=87.72(2)°; R1=0.0326. The most notable structural feature of crystalline6 is the existence of a “secondary” bond [I· ·Cl(2), 2.943(1)Å] between the chloride ion and the iodine atom of the chlorobenziodoxolinone moiety. Further coordination at iodine includes three primary bonds: I-C [2.115(4) Å], I-O [2.145(3) Å], I-Cl(1) [2.454(1) Å]. The entire 1-chlorobenziodoxolinone-chloride sub-structure is planar and exhibits iodine-centered bond angles of 78.8(1)° [C-I-O], 92.0(1)° [C-I-Cl(1)], 97.6(1)° [Cl(2)-I-O] and 91.6(1)° [Cl(2)-I-Cl(1)]. The unit cell of6 contains two loosely packed formula units. The chlorobenziodoxolinone-chloride sub-structures occupy a common plane and exhibit a centrosymmetric relationship, while the tetra-n-butylammonium ions are situated one above and one below the plane. Bonding at the iodine atom in6 is more consistent with a 10-I-3 species electrostatically associated with the chloride ion than a 12-I-4 species such as the tetrachloroiodate ion.