Methoxide ligand

Each triangular face has a triply bridging methoxide ligand and a doubly bridging methoxide group is attached to each base. On the other hand, complexes of the type Cp Ln(Sal)3- and Cp Ln(fur)3 , where Ln = Nd, Yb, n = 1,2 Sal, salicyl aldehyde fur = furfuryl alcohol have been synthesized and found to be susceptible to disproportionation [131]. 

In another example of a dendrimer with a metal cluster core, Gorman and co-workers reported that dendritic ligands with phenoxide groups substituted for triflate or methoxide ligands around an Mo6C18 core to form molecules of the type Mo6(jjl3-C1)8(OR)6, where R = dendrons with zero to two hyperbranches.53... 

Addition of two equivalents of sodium methoxide to Mo6Cl12 in methanol leads to [MosCIgChlOCH ]2 (37). Single-crystal X-ray diffraction reveals that the methoxide ligands occupy axial positions in a trans geometry (Fig. 7). However, it is not clear whether the trans... 

This complex contains bridging oxide and methoxide ligands. It was suggested that the emissive state is derived from an MC sp transition. The large Stokes shift (2iv -13,000 cm 0 was attributed to metal-metal interaction. In a later study it has been concluded that this Stokes shift is caused by a Jahn-Teller distortion [94]. 

A closely related methoxide complex [Pt(Me)(OMe)(dppe)] (dppe = diphenylphosphinoethane) inserts perfluoroethylene into the Pt-OMe bond (Scheme 6.65). The mechanism of the reaction is consistent with coordination of the alkene in a rapid preequilibrium, followed by rate determining insertion. It does not involve dissociation of the methoxide ligand since exchange of this ligand with deuterated methanol is too slow to account for product formation, and the reaction of perlluorocyclopentene in deuterated methanol does not afford a deuterated product (Eq. 6.36) [206]. 

A cupric ion-initiated chain oxidation of substrate does not occur under reaction conditions [260]. In the absence of oxygen the cupric complex yields a stoichiometric amount of the dienoxy radicals which combine to give dehydrodimers. The active cupric complex was shown to have a methoxide ligand and only three pyridine ligands. 

Scheme 6.7 Gas-phase catalytic cycles for the oxidation of methanol to formaldehyde. Reaction 2 is a key CID reaction ofthe methoxide ligand, which produces two isomeric products [77].

Theoretical studies on four- and five-coordinate palladium(ii) model complexes containing a methyl, carbonyl, and methoxide ligand have been carried out, and the results obtained are in agreement with the above experimental observations. A kinetic and thermodynamic preference for insertion into the Pd-OMe bond over Pd-Me is found. The activation energy for methoxide migration was calculated to be between 33 and 42 kj mol compared to 62 and 73 kj moP for methyl migration in the same complexes. 

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