Ni-2,3-thiophenedithiolate Anions in New Architectures: An In-Line Mixed-Valence Ni Dithiolene (Ni4–S12) Cluster

Authors

  • Ana I. S. Neves,

    1. Department of Chemistry, Instituto Tecnológico e Nuclear/CFMC-UL, Estrada Nacional no. 10, 2686-953 Sacavém, Portugal, Fax: +351-219946185
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  • Isabel C. Santos,

    1. Department of Chemistry, Instituto Tecnológico e Nuclear/CFMC-UL, Estrada Nacional no. 10, 2686-953 Sacavém, Portugal, Fax: +351-219946185
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  • Laura C. J. Pereira,

    1. Department of Chemistry, Instituto Tecnológico e Nuclear/CFMC-UL, Estrada Nacional no. 10, 2686-953 Sacavém, Portugal, Fax: +351-219946185
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  • Concepció Rovira,

    1. Institut de Ciència des Materials de Barcelona (CSIC) and CIBER-BBN, Campus Universitari de Bellaterra, 08193 Cerdanyola, Spain
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  • Eliseo Ruiz,

    1. Departament de Química Inorgànica and Institut de Recerca de Química, Teòrica i Computacional, Universitat de Barcelona, Diagonal 647, 08028 Barcelona, Spain
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  • Dulce Belo,

    1. Department of Chemistry, Instituto Tecnológico e Nuclear/CFMC-UL, Estrada Nacional no. 10, 2686-953 Sacavém, Portugal, Fax: +351-219946185
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  • Manuel Almeida

    1. Department of Chemistry, Instituto Tecnológico e Nuclear/CFMC-UL, Estrada Nacional no. 10, 2686-953 Sacavém, Portugal, Fax: +351-219946185
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Abstract

A family of salts that was based on the [Ni(α-tpdt)x]n anions (α-tpdt = 2,3-thiophenedithiolate) and the K+ crown-ether cations were prepared and were then structurally and magnetically characterised. In [K(18-crown-6)][Ni(α-tpdt)2], the anion has a square planar coordination geometry with ligand disorder and the cations and anions are segregated in alternating layers in the crystal structure, as was found in the previous [Ni(α-tpdt)2] salts. Two salts were obtained with the [K(15-crown-5)2]+ cation. The expected 1:1 salt was obtained, which had the usual anion square planar coordination geometry for [Ni(α-tpdt)2] but that had a new molecular arrangement based on an anion double chain. In addition, a 2:1 salt was obtained, which had a new anionic geometry, namely, [Ni4(α-tpdt)6]2–, which is an unprecedented example of an in-line mixed-valence Ni4 dithiolene (Ni4–S12) cluster. A compound with an eight-membered tetrasulfide ring, namely a bis(thiophene-2,3-diyl) bis(sulfide), was also obtained. The salts that are based on the paramagnetic [Ni(α-tpdt)2] anion presented interesting magnetic properties that resulted from the competition between the antiferromagnetic (AFM) and ferromagnetic (FM) interactions with a low-temperature cluster glass behaviour, which was associated with the cis-trans ligand disorder.

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