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The kinetics of the copper(I1) catalyzed decarboxylation of 3-0x0-glutaric acid have been investigated in unbuffered solutions at 25 "C and 0.60 M ionic strength, both in the presence of aromatic tertiary amines, and with hydrated copper ions alone. The amines used were 2,2'-bipyridyl and 1,lO-phenanthroline. Equilibrium constants for the formation of the various copper complexes were determined with a copper ion selective electrode, particularly for the species CuAB, where A is the 3-0x0-glutarate ion, and B is an aromatic amine. The kinetic behavior was then interpreted as arising from the simultaneous decarboxylation of all the species present containing a 3-0x0-glutarate ligand. The resulting rate constants indicated that some kinetic effect was transmitted through the copper from the base to the 3-0x0-glutarate, but the effect was relatively small, and the bulk of the catalytic effect caused by the base arose from changes in equilibrium concentrations.Les cinttiques de la decarboxylation de I'acide 0x0-3 glutarique, catalyst par le cuivre(II), ont ete etudites dans des solutions non tamponees a 25 "C et a une force ionique de 0.60 M; ceci a la fois en presence d'amines aromatiques tertiaires et avec des ions hydrates du cuivre uniquement. Les amines utilisees sont la bipyridyle-2,2' et la phtnanthroline-],lo. Les constantes d'equilibre pour la formation des divers complexes du cuivre ont Cte determintes au moyen d'une electrode stlectives en cuivre, specialement dans le cas d'especes CuAB, ou A est l'ion 0x0-3 glutarate et B une amine aromatique. Le comportement cinetique a alors ete interpret6 en fonction d'une decarboxylation simultanee de toutes les especes presentes contenant le ligand 0x0-3 glutarate. Les constantes de vitesse qui en resultent, indiquent qu'un certain effet cinttique est transmis de la base vers 1'0x0-3 glutarate par l'intermediaire du cuivre; cet effet demeure cependant petit et I'importance de I'effet catalytique provoqut par la base provient de modifications dans les concentrations a I'tquilibre. Canadian Journal of Chemistry, 50, 1461 (1972) IntroductionThe decarboxylation of a-keto dicarboxylic acids is catalyzed by transition metal ions (l), and the reaction has been shown to occur through the spontaneous decomposition of the 1 : 1 complex of formula MA, where M2+ is a divalent metal ion, and A2-is the dianion of the keto acid. The catalytic effect of the metal ion may be appreciably enhanced when the 1 : 1 complexes of the metal ion are added instead of simply the hydrated metal ion (2-7). Presumably the decarboxylation now proceeds through a new reactive species, and it is shown in the present work that reasonably consistent rate constants are obtained, if it is assumed that this species is the 1 : 1 : 1 tertiary complex MAB, where B is the amine. Since aliphatic amines and phosphines are relatively ineffective in promoting decomposition, it is presumed that the delocalized n-systems of the aromatic amine are involved. The overall catalytic rate constant, kc,,, is defined by

Equilibrium constants have been measured for the formation of M A species, where M is divalent manganese, cobalt, nickel, or zinc, and A 2 -is the 3-0x0-glutarate ion. Equilibriumconstants havealso been measured for the reactions MB2' + A 2 -e M A B , where B is 2,2'-bipyridyl or 1,lO-phenanthroline. These constants were obtained by p H measurements at 25 "C and an ionic strength of 0.60. The results are compared with those for similar systems, especially as regards the tendency to form ternary mixed complexes of the type MAB.The rates of decarboxylation of the various M A and MAB species have been measured. The resulting rate constants follow the Irving-Williams order for stability constants, except that in both MAB species the cobalt compound decomposed slightly faster than the nickel compound. The aromatic base, which had been found earlier to have very little effect in copper complexes, increased the rate constants appreciably with other metals, especially with manganese and zinc. Usually 1,IO-phenanthroline has a larger effect than 2,2'-bipyridyl. Some possible explanations of the results are considered.Nous avons mesure les constantes d'equilibre dans la formation d'especes MA, ou M est le manganese, le cobalt, le nickel ou le zinc bivalents et A 2 -, I'ion 3-0x0-glutarate. Nous avons egalement mesure les constantes d'equilibre des reactions MB2' + A2-$MAB, oh B est le 2,2'-bipyridyl ou le 1 ,lo-phenanthroline. Ces constantes furent obtenues au moyen de mesures de p H a 25 "C et sous une force ionique de 0.60. Nous comparons les resultats Q ceux de systemes semblables, specialement en ce qui concerne la tendance a former des complexes ternaires mixtes du type MAB.Nous avons mesure les vitesses de dttcarboxylation des especes M A et MAB. Les constantes de vitesse obtenues suivent I'ordre d'Irving-Williams des constantes de stabilite, excepte que dans les deux especes MAB, le compose de cobalt se decompose Iegeremect plus vite que celui de nickel. La base aromatique, chez qui on a trouvk anterieurement tres peu d'effet dans les complexes de cuivre, augmente appreciablement les constantes de vitesse avec d'autres metaux, specialement le manganese et le zinc. La 1.10-phenanthroline possede un plus grand effet que le 7,2-bipyridyl. Nous considerons quelques explications possibles des rCsultats.[Traduit par le journal]Canadian Journal o f Chemistry, 50, 3573 (1972) In recent paper (I), the present authors reported experiments on the effect of two tertiary aromatic amines, 2,2'-bipyridyl and 1,lO-phenanthroline, on the decarboxylation of 3-0x0-glutaric acid, catalyzed by copper ions. It was found that complexes of formula CuAB, where A2-is the 3-0x0-glutarate ion and B is the aromatic amine, were responsible for the enhanced rates of decomposition. Kinetic and equilibrium measurements made it possible to compare the rate constants for decarboxylation of CuAB and CuA species. In fact the rate constants do not differ greatly, and the major enhancement of the rate arises from changes in the equilibria, and hence ...

4‐Phenyl‐triazolindion (I) reagiert mit zahlreichen Olefinen (II) zu den 1‐substituierten Triazolidindionen (III).