Tetrapyridine and Tetrapyrazine TTF Derivatives: Synthesis, Characterization and Preparation of a Bimetallic CoII Complex

✍ Scribed by Sandra I. G. Dias; Ana I. S. Neves; Sandra Rabaça; Isabel C. Santos; Manuel Almeida

• Book ID: 102827742
• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 602 KB
• Volume: 2008
• Category: Article
• ISSN: 1434-1948
• DOI: 10.1002/ejic.200800660

✦ Synopsis

Abstract

The tetra‐substituted TTF‐type donors 4,4′,5,5′‐tetrakis(2‐pyridylethylsulfanyl)tetrathiafulvalene (1) and 4,4′,5,5′‐tetrakis(2‐pyrazylethylsulfanyl)tetrathiafulvalene (2) were prepared and characterized. These donors show a redox behaviour that is comparable with similar unsubstituted TTF donors, with a small increase of the redox potentials due to the electron‐withdrawing effect of the pyridine and pyrazine groups. Single crystal X‐ray diffraction analyses show structures with a strong segregation of TTF and azo moieties. The pyridine‐substituted donor 1 was used as a bridging ligand to prepare a dinuclear Co^II^‐coordination complex [1Co~2~(hfac)~4~] (hfac = hexafluoroacetylacetonate) with redox properties identical to that of 1. This dinuclear complex presents an effective magnetic moment of ca. 8 μ~B~, corresponding to nearly independent S = 3/2 spins with weak antiferromagnetic interactions below 65 K. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)