Ligands bidentate covalent

A chiral transition metal catalyst generally consists of a metal atom ligated by a chiral organic molecule. This coordination complex can influence the outcome of a reaction by interacting with a substrate. This interaction involves coordination of the substrate to a vacant site on the metal atom. The ligand is covalently bound to the ligand via donor atoms such as P, N, O or S, typically in a bidentate fashion to form the chiral metal complex (Fig. 4.2). The complex can transfer its chiral information to a substrate when it binds to the metal. The nature of the donor atoms and the backbone through which they are linked can have a profound effect on the... 

Despite the obvious beauty of this approach and the enormous research work dedicated to its technical realization there is no example of a covalently surface bonded hydroformylation catalyst in industry so far. The main difficulty that has been encountered is unacceptably high metal leaching from the support, mainly due to unfavorable ligand-metal complexation equilibria. Therefore, the best results have been reported for bidentate, covalently anchored ligands, with Rh leaching in the range 100-1000 ppb. Other drawbacks of the approach in... 

An alternative way for the generation of a bidentate ligand makes use of a self-assembly process of monodentate to bidentate ligands employing non-covalent interactions [87]. 

Monodentate (monometallic monoconnective) phosphor-1,1-dithiolato ligands are rare. Bidentate (monometallic biconnective) form chelate rings and three sub-types can be distinguished according to the degree of asymmetry (Scheme 2). The most asymmetric type (anisobidentate) occurs when a covalent bond is associated with a secondary bond this takes place mostly in main-group metal complexes. The second type is rare and is the result of the association between a covalent and a dative coordinate bond. The symmetric bidentate bonding (isobidentate) is found mainly in transition metal complexes. 

Define monodentate, bidentate, hexadentate, ligand, complex ion, chelate, chelating agent, masking, masking agent, formation constant, coordinate covalent bond, water hardness, aliquot. 

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