Vanadium aryloxides

Table 2 Known alkoxide, dialkoxide, aryloxide, diaryloxide, and dicarboxylate vanadium(V) complexes and their characterization in both organic and aqueous solvent... 

Vanadium(IV) forms complexes with charged carboxylate, aryloxide and alkoxide functionalities as well as the neutral carbonyl group. The steric crowding of the /-butoxides allowed structural characterization of the tetraalkoxide (96) by gas-phase electron diffraction.475 Vw phenoxide complexes derived from ligands such as 2-(dimethylaminomethyl)phenol and 4-chloro-2-[(dimethylamino)methyl]phenol are active as ethylene and propylene copolymerization agents 476 Complexes with silanoxides have been prepared by the oxidation of Vnl complexes.477... 

It has been concluded that the interaction of an analogous vanadium complex with hydrocarbons does not occur by a simple ct bond metathesis mechanism [35b], The alkylidene tantalum(V) complexes undergo intermolecular cyclo-metalation of the aryloxide hgand [35c] (Scheme VIII.5). 

In other systems, N—cleavage gives bis(/i-nitrido)dimetal diamond cores as the products of N2 cleavage. A reduced niobium complex of calix[4]arene reduces N2 in the presence of sodium metal, and a number of intermediates can be isolated. A related tridentate aryloxide ligand also splits N2 to give a diamond core with lithium ions bound to the nitrides. A vanadium diamidoamine complex reacts with N2 to give a product with a similar core structure, which may be further reduced by potassium graphite to a compound with one unpaired electron. This... 

For vanadium, the use of available lower valent hahdes has allowed the isolation of simple aryloxides with the metal in a variety of formal oxidation states (Table 6.24). Important mononuclear examples include [V(OC6H3Me2-2,6)3(py)2] and square planar [V(OC6H2Bu2-2,6-Me-4)2(py)2]. A variety of vanadium(v) aryloxides [(X)V(OAr>3] have also been isolated containing oxo (X = and imido (X = nr)388-390... 

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