Thiones metal complexes

The preparation of a series of transition metal complexes (Co. Ni. Pd. Pt, Ir. Au. Cu. Ag) with ambident anion (70) and phosphines as ligands has been reported recently (885). According to the infrared and NMR spectra the thiazoline-2-thione anion is bounded through the exocyclic sulfur atom to the metal. The copper and silver complexes have been found to be dimeric. 

Triazine-3-thione, 5,6-diphenyl-Friedel-Crafts reaction, 3, 409 metal complexes, 3, 456... 

Recent reports on transition metal complexes of 2-heterocyclic thiosemicar-bazones suggest that stereochemistries adopted by these complexes often depend upon the anion of the metal salt used and the nature of the N-substituents. Further, as indicated previously, the charge on the ligand is dictated by the thione-thiol equilibrium which in turn is influenced by the solvent and pH of the preparative medium. Many of the reported complexes have been prepared in mixed aqueous solvents, often with bases added. However, there are few reports in which workers have varied the nature of their preparations to fully explore the potential diversity of these ligands. 

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. 

Electrostatically-controlled pre-association interactions have an important effect on rates for [Pd(dien)Cl]+ reacting with thione-containing nucleosides, nucleotides and oligonucleotides, as is often the case for reactions between metal complexes and this type of biological ligand. Interaction between the charged complex and the polyanionic oligonucleotide surface leads to an increase in both enthalpy and entropy of activation in the DNA or model environment (252). 

Transition Metal Complexes of l-(2-Methylphenyl)-4, 4, 6-Trimethyl Pyrimidine-2-thione Synthesis and Biological Studies... 

M(dmit)2 complexes (dmit = C3S52- = l,3-dithiole-2-thione-4,5-dithio-late) constitute one of the most important subclasses. The most studied metal complexes are those of group 10 (Ni, Pd, Pt), which possess a square-planar geometry see for instance the molecular structure of the monoanion [Ni(dmit)2], Figure 42.73... 

Cassoux P, Valade L, Kobayashi H, Kobayashi A, Clark RA, Underhill AE (1991) Molecular metals and superconductors derived from metal complexes of l,3-dithiol-2-thione-4, 5-dithiolate (dmit). Coord Chem Rev 110 115-160... 

Infrared data have been tabulated for benzotriazole and a wide range of its transition metal complexes or adducts (172). Far infrared spectra have been recorded for copper(II) benzotriazole adducts and bands at 270-320 cm-1 have been assigned to Cu-N vibrations (172). Infrared absorptions at approximately 825, 800, and 775 cm-1 in the spectra of cobalt(III)/4,5-disubstituted triazolate complexes have been attributed to triazolate ring vibrations (109). Infrared data have been reported and assignments made for palladium and platinum thiatriazoline-5-thionate complexes (37) and for the parent thione (127). Vibrational spectroscopy has been employed in an attempt to determine coordination sites for a range of 8-azapurine complexes (108). 

With Chiral Bis(oxazoline)/metal Complexes Several research groups have developed chiral Lewis acids by using chiral 1,3-bis(oxazoline) ligands for asymmetric Diels-AIder reactions. Evans designed C2-symmetric bis(oxazoline)/Cu(II) complexes derived from chiral bis(oxa-zoline)and Cu(OTf)2, and applied them to asymmetric cycloadditions of acryloyl oxazolidinones and thiazolidine-2-thione analogues. Attractive features of this catalyst system include a clearly interpretable geometry for the catalyst-dienophile complex, which rationalizes the sense of asymmetric induction for the cycloaddition process [26] (Eq. 8A.14). 

Among the heterocyclic thiones, we present in Tables 20-25 the metal complexes of some of the thiocarbonyl ligands most widely used, which are represented in Figure 3. In these tables, data are given from 1988. In the case of copper, only complexes reported since Raper s review28 are given. 

Another very important group of organic acceptors employed as components for organic metals during the last decade is presented by dithiolene metal complexes [e.g., l,3-dithiole-2-thione-4,5-dithiolate (dmit) ligand and... 

---