Supramolecular interaction patterns in the zinc(II) dichloride and tin(IV) tetrachloride complexes with dipyrido[f,h]quinoxaline-6,7-dicarbo-nitrile

• Published in: Acta crystallographica. Section C, Crystal structure communications Vol. 64; no. 3; pp. m123 - m126
• Main Authors: Kozlov, Leonid, Goldberg, Israel
• Format: Journal Article
• Language: English
• Published: 01-03-2008
• ISSN: 0108-2701
• DOI: 10.1107/S010827010800303X

This study characterizes the supramolecular synthons that dominate the intermolecular organization of the title compounds, namely dichloridobis(dipyrido[f,h]quinoxaline6,7-dicarbonitrile)zinc(II), [ZnCl2(C16H6N6)2], (I), and tetrachlorido (dipyrido [f,h] quinoxaline-6,7-dicarbonitrile)tin (IV), [SnCl4(C16H6N6)], (II), in their respective crystal structures. Molecules of (I) are located on 2b axes of rotational symmetry. Their crystal packing is stabilized mostly by pi-pi stacking and dipole-dipole attractions between the organic ligand fragments of inversion-related neighbouring species, as well as by weak intermolecular C-H* * *N hydrogen bonds. On the other hand, Cl* DY *pi and N* * *pi interactions seem to direct the crystal packing in (II), which is unusual in the sense that its aromatic fragments are not involved in pi-pi stacking. Molecules of (II) are located on 11lb planes of mirror symmetry. This study confirms the diverse structural chemistry of this organic ligand, which can be involved in a wide range of supra-molecular interactions. These include effective coordination to various metal ions via the phenathroline N-atom sites, pi-pi stacking and pi * * * halogen contacts through its extended pisystem, and hydrogen bonding and N* * *pi interactions through its nitrile groups. The competing natures of the latter make it difficult to predict a priori the preferred supra-molecular motif that may form in a given structure.