Of coordinated nitrile

The reactivity of coordinated nitriles towards nucleophiles, and electrophiles when deprotonated, has been of major interest. Addition of OH- to the nitrile carbon occurs readily in alkaline solution, kobs = oh[OH-]) and the rate is increased some 106—107 times by coordination (equation 24).176177 k0H has values of 1-50mol-1 dm3 s 1 for R = alkyl177 [e.g. 3.4 (Me) 35 (CH=CH,)j and varies over a wider range for substituted benzonitriles following a Hammett relationship.For 2-cyanoben-zonitrile addition of one equivalent of OH is followed by intramolecular amidine formation on treatment with further alkali (29), or by rearrangement in acid and hydrolysis to the diamide (31), or cyclization to the alternative amidine isomer (32 Scheme 17).179 The alkaline hydrolysis of the... 

Reduction of coordinated nitrile to the parent amine can be accomplished with NaBH4 in slightly... 

Neighbouring-group participation in the hydrolysis of coordinated nitriles has also been investi-gated. The hydrolysis of (93) has been studied for R = H (fcoH = 1050 s , LH =... 

Reactivity of Coordinated Nitriles (A.J.L. Pombeiro, Vadim Yu Kukushkin). 

Reactivity of Coordinated Nitriles 1.39 Solid State Methods, Hydrothermal... 

This last reaction, the hydrolysis of coordinated nitriles, has been extensively studied by Ford and co-workers acidic hydrolysis of [Rh(NH3)5NCO] has been used as an alternate route to the hexaammine (equation 113). The reaction was shown to go through a carbamic acid intermediate, which was isolated and characterized. The kinetic study of the hexaammine formation was complicated by the presence of these two consecutive reactions, and by two different reaction paths. The mechanism proposed for the hydrolysis of the coordinated cyanate is shown in Scheme 14 at low acid concentrations (0.005 to 0.025 M) the rate determining step is HjO attack of the protonated species leading to a rate expression which is first-order in [H ] rate = ky [RhlfH" ]. At higher acid concentrations (0.2 to 1.0 M), decomposition of the carbamic acid complex is rate determining, and... 

The hydrolysis of coordinated nitriles has recently attracted some attention. A very facile hydrolysis of nitriles to the corresponding amides at platinum(IV) centers has been described.The complex [Cu(H2NCOCH2CONHNH2)Cl] is formed from the reaction NCCH2CONHNH2 the copper(II) both promotes the hydrolysis and is reduced to copper(I). The hydrolysis of 2-cyanopyridine to 2-pyridinecarboxamide is accelerated several hundred times by the copper(II) complexes of the ligands (21) and (22). In the case of the (22) some picolinic acid was formed, resulting from the intramolecular attack of alkoxide to yield an intermediate iminoester. ... 

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