Methanol— anionic ligands

A slightly different pattern of reactivity is seen when 3.8 interacts with antimony(m) fluoride in methanol. In this case, the product contains a ligand derived from the hemia-cetal, but the hydroxy group is deprotonated and co-ordinated to the metal centre, to give an N,iV,0-bonded anionic ligand (Fig. 3-17). It is not known whether the co-ordination of the oxygen to the metal centre occurs after the hydration reaction (in which case we are... 

It must be stressed that the above arguments are conjecture, and that the possibility of the presence of an undetectably small but finite concentration of an active hydrido-complex cannot be excluded on the basis of available data.The above systems are not simple, and the presence of more than one parallel mechanism is possible. Comparison of the activities of complexes with different anionic ligands (see Table 1) was made by comparing methanol solutions.Acetone and other strong donor solvents form... 

Also, several P-S (phosphino-thiolate) anionic ligands which form five- and six-membered chelate rings have been evaluated as catalysts for the methanol carbonylation. When using these ligands, the catalyst precursors are... 

The methanol can be removed by heating gently in vacuo. Similar compounds can be made with other carboxylate groups, either by using this method or by heating the acetate with excess carboxylic acid. Treatment of the anhydrous carboxylate with various neutral ligands (L) or anionic donors (X-) forms Rh2(OCOR)4L2 and [Rh2(OCOR)4X2]2-, respectively. The colour of the adduct depends on the donor atom in L (or X) ... 

An extension of the research on silver complexes with Lewis base-functionalized mono(A-heterocyclic carbene) ligands has been made toward the better-studied and stronger coordinating phosphine systems. The reaction of a diphenylphosphine-functionalized imidazolium salt with silver oxide in dichloromethane affords a trinuclear silver carbene complex 50, as confirmed by electrospray-ionization mass spectrometry.96,97 Metathesis reaction of 50 in methanol using silver nitrate gives 51 in 33% yield. The crystal structures of 51 were found to be different when different solvents were used during crystallization (Scheme 12).97 One NO3- anion was found to be chelated to... 

The Ru-BINAP diacetate complex, which gives good results in the enantio-selective hydrogenation of various ketones, is ineffective in the hydrogenation of methyl 3-oxobutanoate. Reactivity in methanol is low, and the enantioselectivity is discouragingly poor. As the carboxylate ligands in Ru complexes may also be replaced by other anions, it is possible to introduce a strong acid anion by... 

The reactions involved are unimolecular, and the cyclohexenyl derivative 3 undergoes solely the spontaneous heterolysis while both spontaneous heterolysis and ligand coupling occur with the iodane 14. The relative contributions of the two reactions of 14 depend on the solvent polarity. The results summarized in Table I show that the iodonium ion and the counteranion are in equilibrium with the hypervalent adduct, X3-iodane. The equilibrium constants depend on the identity of the anion and the solvent employed, and the iodane is less reactive than the free iodonium ion as the k /k2 raios demonstrate. Spontaneous heterolysis of 3 occurs more than 100 times as fast as th t of the adduct 14 as observed in methanol the leaving ability of the iodonid group is lowered by association by more than 100 times. 

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