Carbon-donor hgands

It is interesting to notice that the complex 58 is also able to react with soft donor hgands such as triphenylphosphine resulting in the formation in very mild conditions of the unexpected orthometallated complex 59 (Scheme 23) [89,91, 92]. The ligand here is linked to the metal through both an aromatic and an ylidic carbon. Other transformations are realized from 58 leading, including the compounds of the previous scheme, to four different structures for the bis-ylide (i) C,C-chelate (ii) C,C-orthometallated (iii) C,C-orthometallated and free ylide (iv) C,C,C-terdentate (Scheme 23). 

Carbodiphosphoranes C(PR3)2 and related ligands CL2 which are also termed double ylides differ from the other carbon hgands which are discussed in this volume in the number of lone electron pairs at the carbon donor atom. Ylides, carbenes, allenylidenes, and cumulenylidenes have one lone electron pair but carbodiphosphoranes have two lone electron pairs with ct and tt symmetry. The bonding situation in a carbodiphosphorane (a special class of CL2 compounds, abbreviated as CDP) is best described in terms of donor-acceptor bonding between the phosphane ligands which serve as cr donor and a naked carbon atom in an... 

Other non-precious metal chalcogenides centers containing cobalt have been also synthesized following the template depicted in Fig. 9. In this woik, the in sitn free-surfactant method for carbon supported COxXy (X = S, Se) based on the decomposition of cobalt carbonyls was obtained. To control the growth of the metal nanoparticles and to prevent agglomeration, the use of stabilizers, e.g., donor hgands, polymers and surfactants, i.e., oleic acid (OA), trioctylphosphine oxide (TOPO), trioctyl-phosphine (TOP) and triphenylphosphine (TPP) are necessary. ... 

The selection of compounds reviewed in this chapter deviates from the Patai rule , which states that only compounds containing C-Au and C—Ag bonds should be discussed. The aim is to describe how the electronic structure of silver and gold is affected by the presence of organic hgands, irrespective of whether or not the formal donor atom is carbon. 

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