1,1-Dithiolato metal complexes

Sodium cyanodithioformate readily, and quickly, dimerizes in water with elimination of sulfur in the presence of transition-metal ions, forming directly, in this process, a dithiolato-metal complex. The general procedures described below have been used in the preparation of most of the bis(dicyanoethenedi-thiolato) complexes described previously6 and also of some tris(cfs-l,2-dicyanoethene-l,2-dithiolato) complexes of the first-row transition metals. Although the yields of these complexes obtained by this method are somewhat lower than those described previously, the method possesses the advantage of speed and relative convenience. 

Mop ol twist angles (0) in tris[dithiolato)metal complexes, ML3... 

Metal complexes of 1,1-dithiolates have been reviewed by Coucou-vanis (1) Eisenberg (2) presented a systematic, structural review of dithiolato chelates, and Stokolosa ct al. (3) reviewed dithiophosphate complexes in detail. Earlier reviews (4-3) covered less recent work in greater detail. Following initial work by Delepine (9), 1,1-dithiolato complexes were more intensively studied between 1930 and 1941 (10-16). There is, however, continuous interest in the synthesis, characterization, electronic structures, and bonding of these complexes. 

The literature concerning the chemistry of transition-metal complexes containing 1,1-dithiolato ligands was extensively reviewed, up to 1968, by Coucouvanis (1). We attempt here to update that excellent account. 

Monodentate (monometallic monoconnective) phosphor-1,1-dithiolato ligands are rare. Bidentate (monometallic biconnective) form chelate rings and three sub-types can be distinguished according to the degree of asymmetry (Scheme 2). The most asymmetric type (anisobidentate) occurs when a covalent bond is associated with a secondary bond this takes place mostly in main-group metal complexes. The second type is rare and is the result of the association between a covalent and a dative coordinate bond. The symmetric bidentate bonding (isobidentate) is found mainly in transition metal complexes. 

Abstract Metal complexes including the dmit2- (1,3-dithio-2-thione-4,5-dithiolato) ligand are the only class of metal bis-dithiolenes to give rise to superconductive molecular materials. This chapter first focuses on the description of these superconductive phases. Further sections describe the association of M(dmit)2 moieties with three types of magnetic molecules, i.e., metalloceniums, radical cations, and spin crossover complexes. 

Copolymers, osmium, 37 315 Copper, 46 174-175, see also Tetranuclear X-block metal complexes, copper 1,1,-dithiolato complexes, 23 254-255, 265-268... 

In the synthesis of the parent dithiolenes, the reaction of the disodium salt of ethylene-cts-dithiolate with metal salts is the only useful method.15 For the preparation of substituted dithiolenes the use of substituted ethylenedithiolates is the most efficient choice. In the synthesis of 1,2-dicyanoethylene-l,2-dithiolato ( mnt ) complexes, it is the only available method.16... 

A number of dithiolato-metal-dye complexes were synthesized117 by adding thionine (TH), tolusafranine (SAF) or methylene blue (MB) to a mixture of a metal salt and Na2(mnt) or H2(tdt). The composition of the products was determined from elemental analyses and valence state considerations. Peculiar stoichiometries were found, e.g. Mn2(mnt)5(SAF)6(OH)2 11H20, necessitating the assumption that equally unusual structures existed. Nonetheless, the molar absorption coefficients of the maximum absorption were larger for the complexes than the free dyes. In hexa-methylphosphoramide, the metal dithiolene accelerated the rate of photochemical reduction versus the free ligand with TH but retarded the rate for the SAF and MB complexes. 

Ray K, DeBeer George S, Solomon El, Wieghardt K and Neese F 2007 Description of the ground-state covalencies of the bis (dithiolato) transition-metal complexes from x-ray absorption spectroscopy and time-dependent density-functional calculations. Chemistry-A European Journal 13(10), 2783-2797. 

---