Aryloxide ligands

Tripodal Carbene and Aryloxide Ligands for Small-Molecule Activation at Electron-Rich Uranium and Transition Metal Centers Karsten Meyer and Suzanne C. Bart... 

Fig. 16.2 The Nbvand Tav hydride complexes containing bulky aryloxide ligands (as described by Rothwell).

Arene hydrogenation catalysts based on other metals than late transition ones are less numerous. Of particular relevance are the results reported by Rothwell, who found that Nbv and Tav hydride complexes containing bulky aryloxide ligands (Fig. 16.2) are active for the homogeneous hydrogenation of arenes [30]. 

Aryloxide ligands, thorium, 24 770 Aryloxides, uranium complexation with, 25 436-437... 

TRIPODAL CARBENE AND ARYLOXIDE LIGANDS FOR SMALL-MOLECULE ACTIVATION AT ELECTRON-RICH URANIUM AND TRANSITION METAL CENTERS... 

As with the starting complex, 4 -U, the uranium ion is displaced below the plane formed by the aryloxide ligands by 0.66 A for... 

Isotropically shifted resonances associated with the aryloxide ligands and obtain in CH3CN-d3 solution, they represent resonances associated with the 2 1 adducts that are predominant in solution. Doublets that correspond to the o- p- and m- protons of the 1 1 adduct, that exists in equilibrium with the 2 1 adduct, are not listed. 

Table 1. Monomeric A1R1R2R3 complexes incorporating simple, monodeprotonated aryloxide ligands (Rl) and, where appropriate, Lewis base (L). R2, R3 = other ligands, C.N. = coordination number of the metal... 

Tripodal Carbene and Aryloxide Ligands for Small-Molecule... 

Aromatics. A new generation of homogeneous arene hydrogenation catalysts was developed by Rothwell and coworkers. These are hydride derivatives of niobium and tantalum with bulky ancillary aryloxide ligands (see, i.e., 43) exhibiting high regio- and stereoselectivities 467... 

The use of unsubstituted or 4-methyl phenols resulted in the formation of cluster compounds [58]. However, 2,6-di(fcrt-butyl) substituted aryloxide ligands allowed the isolation of mononuclear 3-coordinate homoleptie complexes of the lanthanide elements, the coordination mode of which was first demonstrated with the N(SiMe3)2 ligand [59], The 2,6-substitution pattern is very effective because the alkyl groups are directed towards the metal center and impose a steric coordination number onto the metal which is comparable to the Cp ligand (Cp 2.49 OC6H3rBu2-2,6 2.41) [60],... 

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