Transition metal complexes with sulfur

Multidentate sulfur ligands mainly derived from 1,2-benzenedithiol have furnished a large number of transition metal complexes with multifarious structures, electronic properties, and reactivity features. This chapter emphasizes the reactivity of complexes that, in the end, were found in the quest of competitive catalysts for nitrogenases and other metal-sulfur enzymes. The... 

Bayon JC, Claver C, Masdeu-Bulto AM (1999) Homogeneous catalysis with transition metal complexes containing sulfur ligands. Coord Chem Rev 193-195 73-145... 

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. 

A variety of routes is available for the preparation of metal-thionitrosyl complexes. The most common of these are (a) reaction of nitride complexes with a sulfur source, e.g., elemental sulfur, propylene sulfide or sulfur halides, (b) reaction of (NSC1)3 with transition-metal complexes, and (c) reaction of [SN]" salts with transition-metal complexes. An example of each of these approaches is given in Eq. 7.1,... 

A variety of polysulfido complexes of transition metals has also been synthesized by the reactions of low-valent metal complexes with elemental sulfur. 

Metal complexes of ligands containing a sulfur donor in conjunction with nitrogen, oxygen or a second sulfur have been reviewed in the past [11-13]. For example, reviews of the coordination compounds of dithiophosphates [14], dithiocarbamates [15, 16], dithiolates [17], dithiodiketonates [18], and xanthates [16] have appeared. The analytical aspects [19] and the spectral and structural information of transition metal complexes of thiosemicarbazones [20, 21] have been reviewed previously. Recent developments in the structural nature of metal complexes of 2-heterocyclic thiosemicarbazones and S-alkyldithiocarbazates, depicted below, are correlated to their biological activities. 

This book clearly demonstrates that transition-metal complexes of chiral sulfur ligands are nowadays powerful catalysts in a considerable number of reactions, although, they have been generally less investigated than complexes with other donor atoms, since the interest in this chemistry is much more recent. In this book, the author has attempted to systematise the role that chiral... 

The UV/visible absorption spectra of [MoO S4 ]2 (n = 0-2) complexes are dominated by the sulfur-to-metal charge transfer transitions of the anion and these bands often serve to characterize the particular system, even though these absorptions may be correlated with those of the parent anion.4 The reduction in symmetry due to complex formation often leads to a broadening or splitting of the bands and, in the majority of the d transition metal complexes, the lowest energy band is red-shifted by an amount which is dependent both upon the nature of the transition metal and the number of such metals bound per MoviO S4 group. 

The stabilization of these heteroaldehydes and -ketones by coordination to transition metals is the subject of this review. Many problems connected with the high reactivity of these heterocarbonyl compounds can be circumvented by using their transition metal complexes. The chemistry of organo-sulfur and organoselenium transition metal complexes in more general terms30,31 and some aspects of thio- and selenoaldehydes and -ketones as... 

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