Homoleptic dithiolenes ligand types

To underpin the syntheses, properties, and applications of dithiolene molecules, this chapter presents a comprehensive discussion of structurally characterized homoleptic dithiolene complexes. That is, the structural unit must contain dithiolene ligands as the only ligand type, and there must be only one type of dithiolene ligand. Emphasis is placed on structural aspects such as coordination geometries, bond distances and angles, and on identifying trends related to the specific dithiolene ligand and the identity and formal oxidation... 

Despite the diversity of ligand types, more than one-half of all structurally characterized homoleptic bis(dithiolene) complexes contain the mnt or dmit ligands (Table II A and B, Entries 1 and 30 Fig. 1). Extended packing arrangements of some mnt complexes are addressed by Lewis and Dance (18). Investigations of the dmit ligand and associated derivatives with a wide range of different cations account for the numerous examples. 

Third-order NLO effects, of interest for potential applications, for example in optical limiting ° impose no symmetry constraints. Thus, studies on this type of nonlinearity have addressed both homoleptic and heteroleptic 1,2-dithiolene complexes. Among the members of the former class, study on TBA salts of monoanionic nickel Al5(l,2-dithiolene) complexes with ligands such as phdt , dddt , pddt , cddt, and -substituted 1,2-diphenyl-1,2-ethyl-enedithioate ° have been published. Underhill and co-workers have reported on the nonlinear properties of unsymmetrically substituted w(l,2-dithiolene) complexes, such as iw[l-butyl-2-phenylethene-l,2-dithiolato(2 )-S,S ]nickel(II), embedded in PMMA-based composites (PMMA=polymethylmethacrylate), or in sol-gel materials.As regards the latter class, some works have dealt with complexes containing mnt and dmit ligands. ... 

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