Dialkyl metal complexes

Relative differences between S 2p3/2 and O 1 s ionization potentials show a characteristic separation for oxygen-bound and sulphur-bound sulphoxides. It is clearly shown in Table 20 that sulphur-bound complexes have (O 1 s-S 2p3/2) relative shifts of 365.0 eV, while oxygen-bound complexes have relative shifts of 365.8 eV. Infrared and X-ray crystallographic results also show that most neutral platinum and palladium dialkyl sulphoxide complexes contain metal-sulphur rather than metal-oxygen bonds, while first-row transition metals favour oxygen-bonded sulphoxide. 

Methods for the preparation of tris(0-ethyl dithiocarbonato) complexes of chromium(III), indium(III), and cobalt(III) are presented and serve to illustrate procedures applicable to the preparation of O-alkyl dithiocarbonato, alkyl trithiocarbonato, iV,A7-dialkyldithiocarbamato, and 0,0 -dialkyl dithiophosphato complexes of several metals. 

Metal complexes, dialkyl thiophosphates and dialkyl thiocarbamates of Zn, Ni, Ba, and Ca, in particular, are widely used for the stabilization of lubricants [30-32,34]. At moderate temperatures (350 400 K), these inhibitors are less efficient than phenols, but they are more potent at higher temperatures (430 480 K). The sophisticated mechanism of action of these antioxidants involves their reactions with hydroperoxide. The interaction of hydroperoxide with metal dialkyl thiophosphates induces a cascade of reactions [5,66-69],... 

Complexes of 2,2 -Dialkyl( ethanediylidenedinitrilo )diethanethiols. The previously unknown Schiff base derivatives of a-diketones with -mercaptoalkyl-amines should be ideally suited to form metal complexes in which the ligand is coordinated in a planar tetradentate manner. Further, the mercaptide functions should occupy cis positions in the coordination sphere of the metal ion. Structure V illustrates the structure expected for such substances. Three products might... 

The As—N bond is labile and this has been widely exploited in synthetic arsenic chemistry. Some idea of the versatility168 can be seen from Schemes 1 and 2. Refluxing secondary amines with tris(dimethylamino)arsine effects transamination (equation 6). These tris(dialkyl-amino)arsines undergo the general reactions in Scheme 1, enabling ready access to a wide variety of compounds, many of them finding use as ligands in transition metal complexes (see Chapter 14 of this work). 

The metal complexes of diethyl dithiophosphate were first investigated in 1931,134 when it was shown that the transition metal complexes [M((EtO)2PS2 ] (n = 2 or 3) were similar to those of xanthates and dialkyl dithiocarbamates, containing a four-membered XSMS (X = C or P) ring. A... 

The reaction of carbonyl sulfide with [M(02)(PPh3)2] (where M = Pd or Pt) has resulted in the first reported examples of transition metal complexes of the monothiocarbonate anion (47 R = O-). Bidentate S—O coordination was concluded from 3IP H NMR analyses of these compounds.184 A short structural review of metal complexes of monothiocarbamate ions (47 R = N(R )R") demonstrates their varied coordination chemistry.185 In complexes of the dialkyl forms the sulfur atom is seen to have considerable mercaptide character , whereas aromatic amine derivatives demonstrate C—S and M—S partial multiple bonding.185,251 A review on the coordination chemistry of these ligands has appeared.186 Additional detail is provided in Chapter 16.4 of this volume. 

Scheme 11. Stepwise alkylation of diethylcyclopentadiene (57,59), yielding isomeric mixtures of triethyl-, tetraethyl-, and pentaethylcyclopentadiene. In analogy to the perisopro-pyl-Cp s (see Scheme 10), purification of the nongeminally dialkylated forms is achieved via conversion to the alkali metal salts and further to transition metal complexes (56).

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