Five varieties of hydrogen bond in 1-formyl-3-thiosemicarbazide: an electron density study

Abstract

In an attempt to investigate the putative S-H...N hydrogen bond, we have studied the title compound, 1-formyl-3-thiosemicarbazide, which was revealed in a CSD search as a crystal structure which might show such an interaction. However, a redetermination of the structure at room temperature and careful analysis showed that the earlier study [Saxena et al. (1991). Acta Cryst. C47, 2374-2376] on which the CSD search was based was in error and that the possibility of an S-H...N hydrogen bond is negated. The presence of five other varieties of hydrogen bond (N-H...O, N-H...S, N-H...N, C-H...O, C-H...S) in the crystal packing prompted us to redirect our efforts and to undertake a study of the charge-density distribution at 90 K. The topological analysis of these five varieties of hydrogen bond was carried out with Bader's quantum theory of ;atoms in molecules' and by applying Koch-Popelier's criteria. The analysis reveals that the hydrogen-bond strength is highest for N-H...O and lowest for C-H...S with N-H...S, N-H...N and C-H...O forming the middle order.

Weak interactions in chain polymers [M(μ-X)2 L 2]∞ (M = Zn, Cd; X = Cl, Br; L = substituted pyridine) – an electron density study

“…Table 4 shows that the electron density at the (3, À1) critical point for the non-classical hydrogen bonds ranges between 0.10 and 0.03 e Å À3 . Two recent reports covering C-HÁ Á ÁO interactions report = 0.03 e Å À3 (Munshi et al, 2006) and = 0.02-0.07 e Å À3 (Hü bschle et al, 2008) and find small positive values for the Laplacian, also consistent with our results. For our C-HÁ Á ÁX contacts, the highest electron densities are encountered for intra-strand non-classical hydrogen bonds between the H atom attached to C ortho in the substituted pyridines and the bridging halides.…”

“…This figure is in colour in the electronic version of this paper. density determined for classical moderately strong N-HÁ Á ÁN bonds (Munshi et al, 2006). At the same time, our results indicate that the contribution of the closed-shell interactions between halogen substituents on adjacent pyridine ligands along the same chain only plays a minor role.…”

Hydrogen atoms can be located accurately and precisely by x-ray crystallography

“…The selection was restricted by the following conditions: Only published data sets. Details, CCDC REFCODES, and assignment to references [( 14 , 21 , 23 , 32 , 46 – 92 )] are given in table S1. Only x-ray data sets of at least d = 0.6 Å, to test the effect of resolution.…”

Exploring the rare S—H...S hydrogen bond using charge density analysis in isomers of mercaptobenzoic acid

“…Indeed, the current version of the CSD (Version 5.37, November 2015) has only 60 crystal structures which possess S-HÁ Á ÁS hydrogen bonds out of 160 organic molecules having S-H bonds. Experimental charge density studies predominately show that sulfur acts as a hydrogen bond acceptor (Munshi & Row, 2002, 2005aMunshi et al, 2006Munshi et al, , 2007. In this article, we report the first experimental charge density study on a S atom acting as a hydrogen-bond donor.…”