Benzyl barium complexes

Fig. 1 Homoleptic and heteroleptic benzyl barium complexes (6-7) by Harder and coworkers [28]...

Ylides Coordinated to Metals. - The structure of a barium complex (52) of methylbenzylidenetriphenylphosphorane has been reported. The Ba ion is in contact with both the ylidic- and the benzylic-carbon atoms. Ab initio calculations and NPA charge analysis indicate that the ylidic moiety is highly polarised, P -C . 

The reduced transition metal cation can easily act as a nucleophile to, for example, benzyl halides. The first example of electrocatalysis by a dinuclear complex is the conversion of benzyl bromide into phenyl acetone in the presence of the nickel/barium complex 5, and acetic anhydride. This transformation does not occur in the presence of the corresponding nickel complex 5 in which case only toluene and bibenzyl are formed [ref 12]. 

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