Insight Into the Intermolecular Factors Responsible for theZ,ZConfiguration of Ar–X–N=S=N–X–Ar (X = S, Se) Derivatives in the Solid State

Abstract

AbstractThe molecular and crystal structures of three new derivatives of Ph–S–N=S=N–S–Ph (1), with 2,4,6‐(tert‐C4H9)3C6H2(4), C6F5(5) and 4‐CF3C6F4(6) as peripheral rings, respectively, and one new derivative of Ph–Se–N=S=N–Se–Ph (2), with C6F5(7) as peripheral rings, are reported and discussed in connection with those of the two parent structures1and2and those of the previously studied derivative of1containing 4‐ClC6H4(3) as peripheral rings. For these seven compounds theZ,Zconfiguration is the only one of the three theoretically possible configurations observed in the solid state and this configurational preference can not be explained by intramolecular stereoelectronic effects. Calculation of the packing energies and densities for the six most common space groups revealed that the crystal packing of the parent structure1in theZ,Zconfiguration has a systematic preference over the corresponding packing of1in theZ,Econfiguration by 0.3–4.9 kJ mol–1. As a result, packing forces are most likely responsible for the dominance of theZ,Zconfiguration of the title compounds in the crystal.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)