Linear Tetranickel String Complexes with Mixed Supported Ligands and Mixed‐Valence Units [Ni 2 ] 3+ : Synthesis, Crystal Structure, and Magnetic Studies

Autor: Gene-Hsiang Lee, Chen-Yu Yeh, Che-Wei Yeh, Shie-Ming Peng, Rui-Ren Wang, Isiah Po-Chun Liu
Rok vydání: 2010
Předmět:
Zdroj: European Journal of Inorganic Chemistry. 2010:3153-3159
ISSN: 1099-0682
1434-1948
DOI: 10.1002/ejic.201000145
Popis: The synthesis, crystal structures, and magnetic properties of linear tetranickel string complexes supported by mixed 2-(α-pyridylamino)-1,8-naphthyridine (Hpyany) and N-(p-tolyl-sulfonyl)dipyridyldiamine (H 2 tsdpda) ligands are reported. In comparing the crystal structure of [Ni 4 (pyany) 2 (tsdpda) 3 CI] (1) with that of [Ni 4 (pyany) 2 (tsdpda) 2 CI(H 2 O)](PF 6 ) (2), the one-electron-reduced compound 1 displays shorter Ni(3)-Ni(4) (ca. 2.28 A) and longer Ni(3)-N (ca. 2.02 A) bond lengths. Similar trends have also been observed for axial NCS - -substituted derivatives [Ni 4 (pyany) 2 (tsdpda) 2 (NCS)] (3) and [Ni 4 (pyany) 2 (tsdpda) 2 (NCS) 2 ] (4). These structural variations indicate the formation of a mixed-valence [Ni 2 ] 3+ unit and a three-electron, two-center Ni(4)-Ni(3) σ bond. Magnetic measurements of 2 and 4 show that both terminal Ni(1) and Ni(4) ions are in the high-spin states (S = 1) and are antiferromagnetically coupled. The one-electron-reduced complexes 1 and 3, however, exhibit a delocalized mixed-valence [Ni 2 ] 3+ unit (S = 3 / 2 ), which is antiferromagnetically coupled with the terminal high-spin Ni II ion.
Databáze: OpenAIRE
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