Dimolybdenum tetracarboxylate

Ionizations from the 6 and x levels of dimolybdenum tetracarboxylates have been resolved, but as shown in Table 26,190 not those from [Cr2(02CMe)4]. The location of the ionization from the a metal-metal bonding levels remains uncertain.190,19 Table 26 also contains core electron ionization energies. 

Calculated and Experimental Ionization Energies (eV) for Dimolybdenum Tetracarboxylates... 

Recently, it has been suggested (285) on the basis of ab initio calculations that the second ionization band of dimolybdenum tetracarboxylates contains both the it and o ionizations as opposed to the assignment presented in the text. This interpretation must be viewed with caution because inter alia it requires the degeneracy of the 2EU and 2A,g ion states for a wide range of substituent electronegativity. 

Quadruply bonded dimolybdenum tetracarboxylates are typically synthesised by extended reflux (20-24 hours) of Mo(CO)6 and the carboxylic acid in high-boiling solvents (e.g. diglyme, 1,2-dichlorobenzene) under an... 

O for S substitution [22], This large change in redox potential can alter the reactivity of the MOj core the dimolybdenum tetracarboxylate Mo2(T PB)4 can act as a catalyst for radical addition reactions of polyhaloalkanes to 1-alkenes, whereas amidinate and guanidinate analogs are catalysts for the radical polymerization of methyl methacrylate [23]. 

Unlike the dimolybdenum(II) tetracarboxylates, (especially Mo2(02CCH3)4), which have served as the key starting materials in the development of multiply bonded dimolybdenum chemistry15, the related ditungsten(II) species W2(02CR)4 have not yet found a similar use. This reflects their ease of oxidation, with consequent difficulty of handling. This is especially true for those reactions in which oxidative addition can occur across the... 

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