A database study of the bonding and conformation of bis-sulfonylamide/-imide moieties

Abstract

The bonding and conformational characteristics of bissulfonylamides and analogous imides are compared. Structures (44 altogether) containing R—SO2—NQ—SO2—R′ units were retrieved from the Cambridge Structural Database. They are either neutral (Q-H, alkyl or aryl groups, hereto atoms such as O and S) or charged (Q = e−) and bearing the functions R, R′ = Me, Et or Ph, respectively. The principal conformations of the —SO2—NQ—SO2— bridge (open versus folded) are represented by sodium dibenzenesulfonamide (BSULFA) and dibenzenesulfonimide (NABSUF). In addition to the compounds possessing Q = alkyl or aryl functions, complexes with N-metal bonds could clearly be distinguished. The dominant forms of SVI—X (X = O, N C) bonds are characterized and correlated with the bond angles formed around the S atoms. The marked difference between the archetypes of the S—N bonds (i.e. nitrogen charged or neutral) indicated that the interdependence of the S—X bonds, i.e. the size and the shape of the SVI[O,O′,N,C] tetrahedra, are principally governed by the environment of the N atoms. The conformation symmetry and dissymmetry of the charged and neutral —SO2—NQ—SO2— moieties are described in terms of the internal rotations about the bonds in the R—S—N—S—R′ fragment.