Ligands bidentate sulfur-donor

Fig, 1 provides a listing of the various sulfur donor ligands whose complexes have been the subject of considerable research. The list of ligands in Fig. 1 is not exhaustive since only potentially bidentate ligands are given. The electronic properties of complexes with bidentate sulfur donor ligands are usually similar although their physical properties, e.g., solubility, can vary widely. This review deals primarily with dithio- and diselenophosphate complexes however, related complexes are discussed wherever they are pertinent to the present discussion. 

Other complexes of bidentate sulfur donor ligands "SCHjCHjS"... 

Detailed structural parameters are given in Table 13. On the other hand, the bidentate sulfur donor ligands in [Te (SPPh2)2N 2] form six-membered chelate rings with large normalized bites, b - 1.37, and the complex has an undistorted planar rectangular structure, 4>a = 47.0°, [Pg.60]

A dinuclear selenide complex anion [Au2(M-Se)2(Se4)2] is the product of the reaction" between [AuCN] and Na2 Ses. Square-planar gold(IIl) complexes are readily formed by a variety of bidentate sulfur-donor ligands such as toluene-1,2-dithiolate, maleonitriledithiolate, and dithiocarbamate. On oxidation with CI2 or Br2, [ Au(S2CNR)2 2] forms Au -Au complexes, which may be oxidized further to an Au complex. 

The first molecular, 6-coordinate complexes which proved to adopt a nonoctahedral structure contain the bidentate, sulfur-donor ligands of the general structures, I and II ... 

Recent Advances in the Chemistry of Transition Metal Complexes of Unsaturated Bidentate Sulfur Donor Ligands (Metal Dithienes)... 

Much of the interest in the bidentate sulfur donor ligands was the discovery that trigonal prismatic as well as octahedral coordination could occur. Thus, X-ray studies of Re(S2C2Ph2)3 and V(S2C2Ph2)3 showed trigonal prismatic geometry. However, Gray and co-workers have concluded from electronic spectral measurements that Ti(nrnt) (mnt = maleonitriledithiolate) has a severely distorted octahedral structure. 

Another important class of bidentate ligands in gold chemistry are those composed of sulfur donor ligands such as dithiocarbamates, dithiolates, dithiocarboxylates, dithiophosphinates, dithiophosphates, and so on. The complexes prepared with these ligands are generally of the type Au2(p.-SS)(PR3)2]"+ or Au2(p-SS)(p-PP)] [153-155], [Au2(p-SS)2f [156, 157] or Au3( i-SS)2(PPh3)2 [158]. All these... 

Many of the general characteristics of dithiolene ligands and their metal complexes described in other chapters of this volume are also useful to Nature. A recurring theme of dithiolene coordination chemistry is their ability to stabilize multiple redox states for a wide variety of metals. The access to multiple redox states combined with a propensity for substantial electronic delocalization likely influenced Nature s choice of dithiolene as a chelating ligand over other potential bidentate sulfur donors. 

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