Dithiolenes properties

Karlin, K.D. Dithiolene Chemistry Synthesis, Properties, and Applications, vol. 52. Wiley, New York (2004)... 

Dithiolene complexes with the maleonitriledithiolate (mnt) ligand form highly delocalized systems and are widespread in studies of conducting and magnetic materials. The electronic properties have been extensively studied with various computational methods including Hiickel and extended Hiickel approaches to identify the nature of the orbitals involved in intramolecular and intermolecular interactions. These structural properties allow the complexes to interact in the solid state via short stacking S, S and short interstack S---S contacts.10 4-1048... 

The structures and redox properties of these complexes have been extensively reviewed 170,171 of interest here is the presence of an intense NIR transition in the neutral and mono-anionic forms, but not the dianionic forms, i.e., the complexes are polyelectrochromic. The positions of the NIR absorptions are highly sensitive to the substituents on the dithiolene ligands. A large number of substituted dithiolene ligands has been prepared and used to prepare complexes of Ni, Pd, and Pt which show comparable electrochromic properties with absorption maxima at wavelengths up to ca. 1,400 nm and extinction coefficients up to ca. 40,000 dm3 mol-1 cm-1 (see refs. 170,171 for an extensive listing). 

NIR region (see Chapter 9.13), complexes of 1,2-dithiolene (DT) and related ligands have attracted considerable attention for their (largely cubic) NLO properties. The complex (156) (a.k.a. BDN) is a highly photochemically stable, saturable absorber and has hence found extensive applications in laser Q-switching. The cubic NLO properties of (156) have been studied by DFWM148,403-407 and more recently, Z-scan.408 Time-resolved DFWM has been applied to square planar Co, Ni, Cu, or Pt complexes of 1,2-benzenedithiolate (BDT) or 1,2-aminobenzenethiolate ligands by Lindle and co-workers.409,410... 

In particular, the synthesis and the electrical, magnetic, and optical properties of the title complexes will be concisely reviewed here. Other aspects, of no less importance, such as the reactivity of 1,2-dichalcogenolene complexes27 and the role of 1,2-dithiolene complexes in biology28 or in analytical chemistry29 have been recently reviewed and the reader is referred to the most recent publications for more information.30 52... 

In fact, one of the peculiar properties of the title class of compounds is the ability of the molecular entity to carry a charge which can vary considerably, also assuming fractional values in non-integral oxidation state (NIOS) salts. The different molecular oxidation states are reversibly accessible by chemical or electrochemical means. A good example is the case of fe(l,2-dithiolene) complexes of ds metal ions [such as Ni(II), Pd(II), Pt(II), Au(III)], whose charge can assume values typically ranging between —2 and 0 (see Scheme 4). 

Metal 1,2-dithiolene and 1,2-diselenolene complexes have been exploited for a large variety of diverse applications,115,116,194 198 thanks to their unique molecular properties, exhibited both in solution and in the solid state. In the... 

The solid-state conducting and magnetic properties of 1,2-dithiolene and... 

E.I. Stiefel (ed), Dithiolene chemistry Synthesis, properties, and applications, Progr. Inorg. Chem., 2004, 52. 

Matsubayashi et al. revealed donor abilities of the unsymmetrical diimine-dithiolene complexes [11-14]. The unsymmetrical complexes provided cation radical salts with various anions including I3, Br3 and TCNQ by use of chemical oxidation [11-14]. The electrical resistivities of the cation radical salts measured with their compressed pellets at room temperature are summarized in Table 1. The electrical resistivities of the dmit complexes were very high. The cation radical salts of the CgH4Sg-complexes, which have the BEDT-TTF moiety [22, 23], exhibited lower resistivity than those of dmit complexes, except for [(Bu-pia)Pt(CgH4Sg)] salts. However, crystal structures of these salts were not reported, and details of their electrical properties and electronic states were not discussed based on their crystal structures. 

Karlin KD, Tiefel El (eds) (2004) Dithiolene chemistry synthesis, properties, and applications. In Progress in inorganic chemistry, vol 52. Wiley, New York... 

Keywords M(dmit)2, Metal bis(dithiolene), Metallocenium, Radical cations, Spin crossover, Magnetic properties, Superconductor... 

The first metal bis-dithiolene complex with an SCO moiety as counter-ion was reported in 2005 [99], namely [Fe(sal2-trien)][Ni(dmit)2] (Fig. 8). Usually, [Fe(sal2-trien)]+ is a Fera complex which exhibits very modest magnetic properties a gradual and incomplete spin transition is observed when it is combined with (PF6) and (BPI14), and the complex remains in the LS state with Cl-, I-and (NO3)-. 

Faulmann C, Cassoux P (2004) In Stiefel El (ed) Dithiolene chemistry. Synthesis, properties, and applications (Progress in Inorganic Chemistry), vol 52. Wiley, Hoboken, NJ, p 399... 

Magnetic Properties of Radical, Crystalline Mixed Cyclopentadienyl/Dithiolene Complexes... 

---