Enanti­opure (S)-butan-2-yl N-(4-x-phen­yl)thio­carbamates, x = NO(2), OCH(3), F, and Cl

The structures of (S)-butan-2-yl N-(4-nitro­phen­yl)thio­carbamate, C(11)H(14)N(2)O(3)S, (I), (S)-butan-2-yl N-(4-meth­oxy­phen­yl)thio­carbamate, C(12)H(17)NO(2)S, (II), (S)-butan-2-yl N-(4-fluoro­phen­yl)thio­carbamate, C(11)H(14)FNOS, (III), and (S)-butan-2-yl N-(4-chloro­phen­yl)thio­carbamate, C(11)H(14)ClNOS, (IV), all at 100 K, have monoclinic (P2(1)) symmetry with two independent mol­ecules in the asymmetric unit. The Flack absolute structure parameters in all cases confirm the absence of inversion symmetry. The structures display N—H⋯S hydrogen bonds, resulting in R (2) (2)(8) hydrogen-bonded ring synthons connecting the two independent mol­ecules. Despite the ring synthon, the packing follows two distinct patterns, with (I) and (IV) ‘pancaking’ along the b-axis direction, while the other two ‘sandwich’ in layers perpendicular to the b axis. Crystal morphologies were determined theoretically via the BFDH (Bravais, Friedel, Donnay–Harker) model and agree qualitatively with the experimentally indexed results. One of the butyl substituent of (II) exhibits structural disorder.