Thiolate complexes reactivity

Kruger, H.-J. and Holm, R. H. (1989) Chemical and electrochemical reactivity of nickel(II,I) thiolate complexes - examples of ligand-based oxidation and metal-centered oxidative addition. Inorg. Chem., 28, 1148-55. 

Sellmann, D., Geipel, F. and Moll, M. (2000) [Ni(NHPnPr3)(S3)], the first nickel thiolate complex modeling the nickel cysteinate site and reactivity of [NiFe] hydrogenase. Angew. Chem. Int. Ed. Engl., 39, 561-3. 

As mentioned above, reactions of this type have been widely used in the synthesis of macrocyclic ligands. Indeed, some of the earliest examples of templated ligand synthesis involve thiolate alkylations. Many of the most important uses of metal thiolate complexes in these syntheses utilise the reduced nucleophilicity of a co-ordinated thiolate ligand. The lower reactivity results in increased selectivity and more controllable reactions. This is exemplified in the formation of an A -donor ligand by the condensation of biacetyl with the nickel(n) complex of 2-aminoethanethiol (Fig. 5-78). The electrophilic carbonyl reacts specifically with the co-ordinated amine, to give a complex of a new diimine ligand. The beauty of this reaction is that the free ligand cannot be prepared in a metal-free reac-... 

The synthesis, structures, and reactivities of metal thiolates with group 4 and 5 metals, and the synthesis and study of copper-thiolates have been reviewed. Hg thiolate chemistry has been reviewed and related to the binding of Hg in vivo by metalloregulatory proteins. A range of two-, three-, and four-coordinate Hg thiolate complexes has been prepared, and comparisons with the metalloregulatory protein, Hg-MerR,... 

In addition to complexes with ON donor sets, complexes with bidentate N-donor atoms and other donors have been described. For example, after several solution studies the crystal structure of the bis(L-cysteine methyl ester)oxovanadium(IV) complex showed that the vanadium is coordinated by the amido nitrogens and thiolate sulfurs (128).561 The complexes and reactivity of a series of pyridine-2-thiolate complexes of V(IV, III, and II) have been characterized (129-131).651 The mass spectrometric fragmentation patterns of two of these complexes were investigated and show the formation of six 1 1 complexes and one 1 2 complex in the gas phase.651... 

The Josiphos ligand was selected based on detailed mechanistic investigations of reductive elimination from Pd-thiolate species [83, 85, 86, 106, 111]. Two factors were identified as crucial for the observed reactivity the strong electron releasing nature of this bisphosphine ligand and the suppression of formation of less-reactive bridging thiolate complexes due to the steric demands of the ligand. 

Guimoe recently demonstrated the addition of thiols to electron-deficient alkenes using well-defined Cu-NHC thiolate complexes (31) [255, 256]. The prehminary scope is broad, with a number of potentially reactive electron-withdrawing groups being well-tolerated. Both alkane thiols and arene thiols are effective. In addition, sterically hindered olefins also react efficiently. 

Hydrosulfido complexes, which contain M-SH groups, can react by an additional pathway unavailable to metal-thiolate complexes. Hydrosulfido complexes can react by cleavage of the S-H group to generate metal-sulfido complexes. The synthesis and reactivity of sulfido complexes are described in Qrapter 13 (metal-ligand multiple bonds). 

Abstract. The electrochemical activation of dinuclear molybdenum thiolate complexes and the reactivity of electrogenerated intermediates toward CO, RNC and RCN are described. 

The aim of the present chapter is to review the course of sulfur vulcanization in the light of recently obtained information on the reactivity of some of the intermediates in the process and on the stability of monosulfide crosslinks. All the recent results relate to NR, but reference to previous work with BR allows some major differences in behavior to be discerned. In the case of NR, the key role of zinc accelerator-thiolate complexes in promoting various reactions has been emphasized by the new findings. In addition, the importance of the position of substitution of sulfur on the rubber backbone in determining the subsequent fate of the system has been further underlined. It turns out that neither of these features can play any significant part in the sulfur vulcanizations of BR. 

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