Distortion ligands

Lipkowitz, K.B. and Schefzick, S. (2002) Ligand distortion modes leading to increased chirality content of Katsuki—Jacobsen catalysts. Chirality, 14, 677. 

CuL2C12(H20)2],3H20 ligand, 02 from neighbouring ligand distorted octahedral, trans-bonded ... 

Scheme 4.2 Frontier orbitals of the porphyrins according to the Gouterman four-orbital model for D4h point group (top). In the presence of a perturbation (substituents or ligand distortion) the degeneracy might be lifted (bottom). With permission from Wiley, ref 7a.

The observed standard rate constants, k , for one-electron, outer-sphere redox couples vary over wide ranges . Couples such as [RuCNHj) ] , [Fe bipy)j] and [Cr(bipy)j) (bipy = 2,2 -bipyridine) each exhibit values of k that approach the experimentally observable limit of a few cm s . Because the differ. ice, a, in the metal-ligand bond lengths in the oxidized and reduced stetes are mi - jt S <0.5 nm) for each of these systems , the major component of AG arises frjm the outer-shell (solvent) component AG, which is predicted to be insensitive to the chemical nature of the reactant. Much smaller values of are observed for redox couples that involve greater structural differences between the oxidized and reduced forms, as expected because the inner-shell (metal-ligand distortion) component AG will increase rapidly for larger values of a. 

X —and X —bonds. Thus the driving forces of the L ligand distortion stem from the intraligand and the Pt-L interactions. In addition, the bond involved in the L ligand coordination is weakened by the extent to which the L hgand distortion is reduced. ... 

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