Crystal and molecular structure of an unsymmetrical 6a-thiathiophthen: single-crystal X-ray analysis of 3-benzoyl-5-p-bromophenyl-2-methylthio-6a-thiathiophthen

Abstract

The X-ray structure analysis of an unsymmetrically substituted 6a-thiathiophthen, 3-benzoyl-5-p-bromophenyl-2-methylthio-6a-thiathiophthen, has been carried out on film data collected at 4°C. The crystals are monoclinic, space group P2₁/c, with Z= 8 in a unit cell of dimensions a= 13·60, b= 10·42, c= 27·20 Å, β= 98° 0′. The structure was solved by the symbolic addition method and refined to R 0·13 for 3827 observed reflexions. The two S–S distances in each crystallographically non-equivalent molecule are unequal, with an average ‘short’ S–S length of 2·17 Å, and an average ‘long’ S–S length of 2·51 Å. The detailed molecular structures, and the relevance of the results to ‘no-bond resonance’ are discussed.