2834 Inorganic Chemistry, Vol. 16, No. 11, 1911
(15) (16) (17) (18)
contaminant. Also, the molar extinction coefficients previously reported for ( B U ~ N ) ~ R ~ ~ ( N C S )(see ~ ( Table P P ~ ,111 ) ~of ref 11) should be increased by a factor of 2, since these values were calculated" for the monomeric formulation. A. H. Norbury, Adu. Inorg. Chem. Radiochem., 17, 231 (1975). W. R. Robinson, J . E. Hahn, T. Nimry, and R. A. Walton, unpublished observations. Upon completion of the structure refinement we will publish the full details of this structure determination. For a detailed discussion of this procedure see (a) R. D. Feltham and R. G. Hayter, J . Chem. SOC.,4587 (1964), and (b) A. Davison, D. V . Howe, and E. T. Shawl, Inorg. Chem., 6 458 (1967). From plots of A, (0-I cm2) against C ~ I / ~ ,where c, is the equivalent concentration, we obtained the following hovalues (in a-' cm2): (I) A. = 131; (111) ho= 136; (VI) ho = 90; (X) ho= 101. Thevalue for 111 is very close to that reported previously (140 0-l cm2).11
Duck J. Yang and William L. Jolly (19) F. A. Cotton, Chem. SOC.Rev., 27 (1975). (20) H. P. Gunz and G. J. Leigh, J . Chem. SOC.A, 2229 (1971). (21) R. E. Myers and R A. Walton, Inorg. Chem., 15, 3065 (1976). (22) D. G. Tisley and R. A. Walton, J. Chem. SOC., Dalton Tram., 1039 (1973). (23) S. A. Best and R. A. Walton, Isr. J . Chem., in press. (24) R. R. Hendriksma, Inorg. Nucl. Chem. Lett., 8, 1035 (1974). (25) The only mechanistic information currently available is that re orted by Hynes26for substitution reactions of Re2C182-and Re2Br$ with tri-n-butylphosphine in methanol. (26) M. J. Hynes, J . Inorg. Nurl. Chem., 34, 366 (1972). (27) F. A. Cotton, B. A. Frenz, B. R. Stults, and T. R. Webb, J . A m . Chem. S o c , 98, 2768 (1976). (28) C. D. Cowman and H. B. Gray, J . A m . Chem. SOC.,95, 8177 (1973). (29) F. A. Cotton, N. F. Curtis. B. F. G. Johnson, and W. R. Robinson, Inorg. Chem., 4, 326 (1965).
Contribution from the Department of Chemistry, University of California, and the Materials and Molecular Research Division, Lawrence Berkeley Laboratory, Berkeley, California 94720
A Kinetic Study of the Hydrolysis of 2-Gesmaacetate in Neutral and Alkaline Solutions DUCK J. YANG and WILLIAM L. JOLLY*
Receiued February 14, 1977
AIC70121X
-
In neutral and alkaline solutions, the 2-germaacetate ion decomposes to give germane and bicarbonate (or carbonate): G e H 3 C 0 r t H 2 0 GeH4 H C O r . The rate of this decarboxylation is pM independent and is first order in the germaacetate s-l; the activation energy is 28.6 kcal/mol. In strongly ion. The rate constant at 60 OC and ionic strength 1.0 is 1.62 X alkaline solutions (especially at hydroxide concentrations above 1 M), a second decomposition reaction, producing hydrogen and the insoluble brown polymer H2Ge203-xH20, competes with the decarboxylation: 2GeH3CO< + 2 0 H - (3 x)HzO 6Hz H 2 G e 2 O 3 a H 2 0 2C032-. The rate of the latter reaction is first order in germaacetate ion and is inversely proportional to the Hammett acidity function h-, Le., first order in hydroxide ion; -d In (GeH3CO
