Symmetrisation in the Interaction of Chloro[2-(dimethylaminomethyl)phenyl-C1]mercury(II) with Thiosemicarbazone Derivatives of Pyridine-2-carboxamide and Pyrazin-2-carboxamide

Authors

  • Ulrich Abram,

    1. Freie Universität Berlin, Chemisches Institut, Fabeckstr. 34–36, 14195 Berlin, Germany
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  • Alfonso Castiñeiras,

    1. Departamento de Química Inorgánica, Facultad de Farmacia, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain, Fax: +34-981547-163
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  • Isabel García-Santos,

    1. Departamento de Química Inorgánica, Facultad de Farmacia, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain, Fax: +34-981547-163
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  • Raul Rodríguez-Riobó

    1. Departamento de Química Inorgánica, Facultad de Farmacia, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain, Fax: +34-981547-163
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Abstract

Pyridine- and pyrazine-2-carboxamide thiosemicarbazones (HAm4DH and HAmpz4DH) or their N4,N4-dimethyl derivatives (HAm4DM and HAmpz4DM) react with chloro[2-(dimethylaminomethyl)phenyl-C1]mercury(II), [Hg(damp)Cl], to give the tetrahedral [Hg(TSC)2] complexes [TSC = Am4DH (1), Am4DM (2), Ampz4DH (3) or Ampz4DM (4)]. Spectroscopic studies and a X-ray structural analysis show that the potentially tridentate thiosemicarbazones adopt S,N coordination modes, with each deprotonated thiosemicarbazone binding to the HgII centre through the azomethine nitrogen and the thiolate sulfur atoms, whereas the heterocyclic nitrogen atoms are free of coordination. Intra- and intermolecular hydrogen bonding in all complexes and specific C–H···π interactions with the chelate or pyridyl rings of the complexes 1 and 2 were found in the crystal structures. Furthermore, [Hg(damp)Cl] undergoes symmetrisation to give the symmetric unit [Hg(Hdamp)2]2+ in which the Hdamp is protonated at the nitrogen. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

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