Acetonitrile complexes with ammonia, reaction

Both complexes (867) and (868) promote the hydrolysis of urea in a two-step process.2080 Heating of (867) or (868) in acetonitrile solution produced ammonia with kinetic first-order dependence on complex concentration and an observed rate constant of (7.7 0.5) x 10-4 h-1 to yield a cyanate complex as the reaction product. When the reaction was carried out in 50% aqueous acetonitrile solution, ammonia was produced at the same rate but without buildup of the cyanate-containing product, suggesting that the latter is hydrolyzed in the presence of water. The hydrolysis rate was also first order in water, indicating that it occurred by attack of an external water on the coordinated cyanate.2080... 

Another example is found in the various platinum (II) ammines which contain acetonitrile. One such is formed by reaction of [Pt(CH3CN)2Cl2] with ammonia. This gives a product with a formal composition corresponding to [Pt(CH3CN)2(Cl)2(NH3)2]. For many years this was considered to be an unusual complex in which platinum (II) was 6-coordinated. There are very few instances (if any) in which platinum (II) exhibits a coordination number other than 4. It has been shown by x-ray studies (67) that the product of this reaction is [Pt(acetamidine)2Cl2] and that the reaction may be written as shown at the top of the next page. Here, the coordination act accentuates the electron drift from the nitrile carbon atom and makes it more susceptible to attack by nucleophiles—in this case, ammonia. This kind of process had been essentially substantiated by chemical studies carried out previously, and the formation of... 

Ammonia methods with use of metal oxides are of undoubted interest. The yields of formed complex compounds are 60-90% [202]. For example, the reaction (3.271) of diethyleneamine (L) with a powder of ZnO and ammonium thiocyanate in acetonitrile leads to complex 824a (yield 90%) [676] ... 

Complexes having nitrogen ligands such as ammonia, acetonitrile, pyridine and dinitrogen readily undergo exchange reaction with RNC ... 

Since alkylamines are more sensitive to oxidation than liquid ammonia, numerous attempts to find an appropriate oxidant (instead of KMn04), possessing a higher selectivity towards tj -complexes, have been undertaken. For example, alkylaminations of 2-nitrobenzothiophene with primary amines have been performed in various solvents in the presence of such oxidants as AgNOs, H2O2, t-BuOOH, MnOa, or N-methylmorpholine N-oxide. However, yields of 3-aIkylamino derivatives proved to be very low, varying from 0 to 14% [61].The bestresults were obtained with ceric ammonium nitrate (CAN) in water acetonitrile system (Scheme 12). Unfortunately, CAN did not work properly in the reactions with secraidary alkylamines. 

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