SECONDARY REACTIONS OF SULFENES FROM SULFONYL CHLORIDES AND TERTIARY-AMINES .3. CRYSTAL-STRUCTURE ANALYSIS OF BIS(TRIMETHYLAMMONIOSULFONYL)METHANIDE TETRAPHENYLBORATE - N-SIGMA-ASTERISK-INTERACTIONS (HYPERCONJUGATION AND HOMOHYPERCONJUGATION) IN SULFENE AMINE S,N-ADDUCTS

Bis(trimethylammoniosulfonyl)methanide chloride (3b) could be obtained in 97% yield by reaction of methanedisulfonyl dichloride (5) with three equivalents of trimethylamine. X-ray analysis of the tetraphenylborate 3c reveals that the conformation of the cation is determined by n(C)-sigma(S-N)* interactions (negative hyperconjugation) and by n(C)-sigma(N-C)* interactions (negative homohyperconjugation). These effects were deduced from alterations of the bond lengths within the S-N-C chains which are coplanar to the occupied p(z) orbital at the central C atom. Comparison with known crystal structure data shows, that sulfene-amine S,N-adducts generally have the zwitterionic ammoniosulfonylmethanide structure 3, stabilized by n(C)-sigma* interactions.