Abstract
The mol-ecular structure of the title bis-pyridyl substituted di-amide hydrate, C14H14N4O2·H2O, features a central C2N2O2 residue (r.m.s. deviation = 0.0205 Å) linked at each end to 3-pyridyl rings through methyl-ene groups. The pyridyl rings lie to the same side of the plane, i.e. have a syn-periplanar relationship, and form dihedral angles of 59.71 (6) and 68.42 (6)° with the central plane. An almost orthogonal relationship between the pyridyl rings is indicated by the dihedral angle between them [87.86 (5)°]. Owing to an anti disposition between the carbonyl-O atoms in the core, two intra-molecular amide-N-H⋯O(carbon-yl) hydrogen bonds are formed, each closing an S(5) loop. Supra-molecular tapes are formed in the crystal via amide-N-H⋯O(carbon-yl) hydrogen bonds and ten-membered {⋯HNC2O}2 synthons. Two symmetry-related tapes are linked by a helical chain of hydrogen-bonded water mol-ecules via water-O-H⋯N(pyrid-yl) hydrogen bonds. The resulting aggregate is parallel to the b-axis direction. Links between these, via methyl-ene-C-H⋯O(water) and methyl-ene-C-H⋯π(pyrid-yl) inter-actions, give rise to a layer parallel to (10); the layers stack without directional inter-actions between them. The analysis of the Hirshfeld surfaces point to the importance of the specified hydrogen-bonding inter-actions, and to the significant influence of the water mol-ecule of crystallization upon the mol-ecular packing. The analysis also indicates the contribution of methyl-ene-C-H⋯O(carbon-yl) and pyridyl-C-H⋯C(carbon-yl) contacts to the stability of the inter-layer region. The calculated inter-action energies are consistent with importance of significant electrostatic attractions in the crystal.
Highlights
The molecular structure of the title bis-pyridyl substituted diamide hydrate, C14H14N4O2ÁH2O, features a central C2N2O2 residue (r.m.s. deviation = 0.0205 A ) linked at each end to 3-pyridyl rings through methylene groups
Two symmetry-related tapes are linked by a helical chain of hydrogen-bonded water molecules via water-O—HÁ Á ÁN(pyridyl) hydrogen bonds
The analysis indicates the contribution of methylene-C—HÁ Á ÁO(carbonyl) and pyridyl-C— HÁ Á ÁC(carbonyl) contacts to the stability of the inter-layer region
Summary
Complementing hydrogen-bonding interactions, the nLH2 molecules, for n = 3 (Hursthouse et al, 2003; Goroff et al, 2005; Jin et al, 2013) and n = 4 (Goroff et al, 2005; Wilhelm et al, 2008; Tan & Tiekink, 2019c), are well-known to form NÁ Á ÁI halogen-bonding interactions and, some of the earliest studies were at the forefront of pioneering systematic investigations of halogen bonding. It was during the course of ongoing studies into co-crystal formation The layers stack without directional interactions between them, Fig. 2(b)
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