Synthesis, Molecular and Crystal Structure Analysis of 1-(4- Methylbenzenesulfonyl)indole-3-carbaldehyde and DFT Investigation of Its Rotational Conformers

Abstract

Two independent molecules that differ in terms of rotation about the central S-N bond comprise the asymmetric unit of the title compound 1. The molecules have a V-shape with the dihedral angles between the fused ring system and benzene ring being 79.08(6) and 72.83(5), respectively. The packing is mostly driven by π⋯π interactions occurring between the tolyl ring of one molecule and the C6 ring of the indole fused ring system of the other. DFT and IRC calculations for these and related 1-(arylsulfonyl)indole molecules showed that the rotational barrier about the S-N bond between conformers is within the 2.5-5.5 kcal/mol range. Crystal data for C16H13NO3S (1): Mr = 299.33, space group Pna21, a = 19.6152(4) a, b = 11.2736(4) a, c = 12.6334(3) a, V = 2793.67(13) a3, Z = 8, Z' = 2, R = 0.034. © 2014 by the authors; licensee MDPI, Basel, Switzerland.