Mononuclear gold(iii) complexes with diazanaphthalenes: the influence of the position of nitrogen atoms in the aromatic rings on the complex crystalline properties |
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Authors: | Biljana Glii Beata Warajtis Marcin Hoffmann Urszula Rychlewska Milo I Djuran |
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Institution: | University of Kragujevac, Faculty of Science, Department of Chemistry, R. Domanovića 12, 34000 Kragujevac Serbia.; Faculty of Chemistry, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 8, 61-614 Poznań Poland ; Serbian Academy of Sciences and Arts, Knez Mihailova 35, 11000 Belgrade Serbia |
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Abstract: | A series of mononuclear gold(iii) complexes of the general formula AuCl3(diazanaphthalene)], where diazanaphthalene is quinazoline (qz, 1), phthalazine (phtz, 2), 1,5-naphthyridine (1,5-naph, 3), 1,6-naphthyridine (1,6-naph, 4) or 1,8-naphthyridine (1,8-naph, 5), were prepared and fully characterized. The complexes 1–5 consist of discrete monomeric species with the Au(iii) cation in a square planar coordination geometry surrounded by three chloride anions and one diazanaphthalene ligand. Crystallographic studies indicate the presence of an extended 4 + 1 or 4 + 2 geometry around the square planar AuCl3(diazanaphthalene)] center due to Au⋯Cl and Au⋯N interactions. The crystal structures of these complexes are controlled by a variety of intermolecular interactions that utilize the amphiphilic properties of the coordinated chloride anions and involve C–H groups, π-electrons, and an uncoordinated nitrogen atom of the diazanaphthalene ligand. The usual offset π-stacking between the N-heteroaromatic ligands appears to be completely hindered between the 1,5-naph fragments and significantly weakened between the 1,6-naph and 1,8-naph in their respective complexes 3, 4 and 5, for which the average molecular polarizability (α) values are the lowest in the series. It is remarkable that the AuCl3(benzodiazine)] complexes 1 and 2 form centrosymmetric crystals, but the AuCl3(naphthyridine)] complexes 3–5 assemble into non-centrosymmetric aggregates, making them potential alternatives to the previously studied systems for application in various fields by taking advantage of their polarity.The AuCl3(benzodiazine)] complexes form centrosymmetric crystals, while the AuCl3(naphthyridine)] complexes assemble into non-centrosymmetric aggregates, making them potential alternatives for advanced nonlinear optical materials due to their polarity. |
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