STRUCTURAL STUDIES OF SOME O-SUBSTITUTED S-PHENYL THIOBENZOATES .1. CRYSTAL-STRUCTURE OF S-PHENYL O-CHLOROTHIOBENZOATE AND S-PHENYL O-BROMOTHIOBENZOATE

Structural characteristics of S-phenyl o-chlorothiobenzoate (I) and S-phenyl o-bromothiobenzoate (II) have been investigated by single crystal X-ray diffraction. It was shown that the crystals are isomorphous and crystallize in the monoclinic space group P2, with Z = 2. The unit cell parameters are: a = 10.150(3), b = 7.672(2), c = 7.595(2)angstrom, beta = 91.28(1)degrees for C13H9ClOS (compound I) and a = 10.141(3), b = 7.764(2), c = 7.653(2)angstrom, beta = 90.14(3)degrees for C13H9BrOS (compound II). The structures were solved by heavy-atom methods and refined by full-matrix least-squares, from room-temperature data collected with a Philips PW 1100 diffractometer, to conventional R factors of 0.056 for I and 0.044 for II. The structures consist of independent molecules held together by intermolecular interactions. Molecular packing is influenced by the presence of o-substituted Cl or Br atoms. The Cl atoms in structure I as well as the Br ones in structure II are directed to the centers of the pi-electronic system of the o-substituted phenyl rings belonging to the neighboring molecules. The six Cl . . . C and Br . . . C distances range from 3.651(10) to 3.869(9)angstrom and from 3.644(6) to 3.890(6)angstrom, respectively. The Cl (or Br) atom is additionally directed towards the two carbon atoms (C3 and C4) in another o-substituted phenyl ring, the Cl . . . C and Br . . . C distances being 3.786(9) and 3.849(10)angstrom in I and 3.727(6) and 3.881(6)angstrom in II. The torsion angle C6-C7-S-C8 is -170.2(7)degrees in I and 168.6(4)degrees in II. The angles between the planar O-C7-S central fragment of the molecule, on the one hand, and the o-substituted phenyl ring, on the other, are 113.9(3)degrees in I and 110.9(2)degrees in II. The corresponding values for the angles between the O-C7-S fragment and the nonsubstituted phenyl ring are 115.8(3)degrees and 114.3(2)degrees in compounds I and II, respectively.