Hydrogen Bonding to Thiocyanate Anions: Statistical and Quantum-Chemical Analyses

Abstract

A statistical analysis of entries from the CSD (Cambridge Structural Database) showed that the average hydrogen-bond geometry to the nitrogen acceptor atom of the thiocyanate anion was not collinear with respect to the molecular axis of the anion and so not collinear with the nitrogen lone pair [Tchertanov & Pascard (1996). Acta Cryst. B52, 685-690]. This somewhat unexpected result has been investigated further using theoretical energy calculations applying Intermolecular Perturbation Theory in combination with a more detailed statistical analysis of an appropriate CSD dataset. The energy calculations pointed to the formation of the strongest hydrogen bonds in the nitrogen lone-pair direction. The statistical analysis showed that this directionality occurs in cases where the N atom accepts one hydrogen bond only. The non-linear average hydrogen-bond geometry observed in the earlier study can be attributed to multiple hydrogen bonding to the N atom. In such cases, there is a shift away from the optimum orientation.observed frequently (Legon & Millen, 1982;Taylor et al., 1983) and can be ascribed, primarily, to optimization of the electrostatic attraction which is the largest energy contribution to hydrogen-bond formation. It is difficult to draw a general conclusion from the study by Baranovskii et al. (1985), however, as water molecules appear to have special donor features by comparison with other (aliphatic) hydroxyl donors (Tse et al., 1980; Kroon-Bateburg & van Duijneveldt, 1986;Zheng & Merz, 1992). In theoretical calculations (Lommerse et al., 1997) ether O atoms accept water hydroxyl donors in the direction of one of their lone pairs, but methanol hydroxyl donors between their lone pairs. This paper presents a more detailed study of hydrogen bonding to thiocyanate anions. A further statistical survey of CSD information is presented which considers the effect of hydrogen-bond coordination on the mean hydrogen-bond geometry to thiocyanate anions. Theoretical energy calculations using Intermolecular Perturbation Theory (IMPT: Hayes & Stone, 1984) for a suitable model system are also presented.

The Nature of Hydrogen Bonding in Protic Ionic Liquids

“…In crystalline solids, R X:H N of 2 are associated with bifurcated H-bonds [3,6,8,35] and 3 with trifurcated Hbonds, [3,6,8] and similar relationships between R X:H N and Hbond geometry have been reported, notably for dithiocyanate salts, [36] or thiocyanate, [37,38] and sulfate [39] anions in the Cambridge Structural Database. The bifurcated and trifurcated definitions must be applied with caution for PILs because the ions are in motion rather than fixed in a lattice, so the R X:H N and angle distributions represent the average liquid state.…”

Crystallographic Statistical Study of Decavanadate Anion Based-Structures: Toward a Prediction of Noncovalent Interactions

“…CSD have been used extensively in studies of common strong hydrogen bond having oxygen or nitrogen as donors and acceptors. [49][50][51][52][53][54] Nowadays, the noncovalent interactions studies take two directions: i) the study of weak hydrogen bonding; major contribution of CSD analysis have been to support in identification of short C-H⋅⋅⋅O contacts as hydrogen bonds [55][56] or C-H⋅⋅⋅π interaction, 57-58 ii) an increasing interest in the energy crystal landscape. [59][60][61][62] Ferreira da Silva et al, 63 According to our previous paper, we have ranked the oxygen atoms from the most negative to the less negative (Ob, Oe, Oc, Od, Of and Og).…”

Applications of the Cambridge Structural Database in organic chemistry and crystal chemistry

“…Llamas-Saiz et al, 1992;Allen, Lommerse et al, 1997;Bock et al, 1998), but also to a wide variety of weaker hydrogen-bonded systems (see e.g. Rzepa et al, 1994;Steiner et al, 1995;Dunitz & Taylor, 1997;Lommerse & Cole, 1998) and to interactions that are not mediated by hydrogen (see e.g. Lommerse et al, 1996;Allen et al, 1998).…”