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COMMUNICATIONS TO THE EDITOR
(curve f , Figure 1D) could correspond to traces of 1-1 complexes. The spectra of ternary solutions water-acetone-carbon tetrachloride show that, for acetone molar fractions lower than 0.25, water and acetone interact essentially by following a 1-1 stoichiometry. On the contrary, in pure acetone, water at low concentration is almost totally involved in 1-2 complexes and the band around 7078 cm-’ must be related to such complexes, contrary to the hypothesis of McCabe, et al. These authors have indeed made an erroneous extension to water-acetone binary solutions of results obtained, by diff erent techniques, with ternary mixtures water-acetone-1,2dichloroethane where the acetone formal concentration was lower than 0.6 M (molar fraction c 0.05).’0
gives’ a shift of -90 cm-’ towards lower frequencies for each of the v1 and v3 vibrations from those for “free” water in CCI,. However, in the overtone region, the shift for the v(101) band for the 1-2 complex from that of “free” water in CClh is only 85 cm-l. This shift is about half the expected value. The anharmonicity factor would not, we believe, account for this drastic reduction. This, taken together with the fact that the intensity of bonded OH is higher than frec OH in the fundamental while the opposite is true in the overtone r e g i ~ nsuggests ,~ that the peak at 7078 cm-’ could be a composite of a sharp peak (at -7075 cm-I) due to a small amount of a 1-1 complex and a small broad peak at -6980 cm-’ due to the major 1-2 complex. We extended the arguments of a 1-1 complex in water-acetone 1,2-dichloroethane mixtures6 to water-inAcknowledgments. We wish to thank Professor M. acetone mixtures to show the spectral contribution at L. Josien for helpful discussions and Rilrs. R. nil. 7075 cm-1 is due to a 1-1 complex but did not deny the Moravie for her assistance with the experimental work. existence of a 1-2 complex for small amounts of water in large amounts of acetone. There was also another (10) T. F. Lin, 8. D. Christian, and H. E. Affsprung, J . P h y s . Chem., 69, 2980 (1965); T,F. Lin, S. D. Christian and H. E. Affbasis for assigning the 7075 cm-l Gauwian component sprung, ibid., 71, 1133 (1967). in Figure 5 of our paper to a 1-1 complex. Worley and LABORATOIRE DE SPECTROCHIMIE ANDRBBURNEAU* Klotz,6 in their near-infrared studies of HOD in D20, MOLBCULAIRE JACQUES CORSET assigned the peak at 7063 cm-’ to the overtone of free PARIS VI UNIVERSITB OH. Our water-in-acetone spectra had a major peak PARISVe, FRANCE at 7075 cm-’. Recognizing a small difference due to isotopic substitution and dielectric constant of the RECEIVED SEPTEMBER 22, 1971 medium, we assigned the 7075-cm-’ band to the v( 101) of the 1-1 complex. Reply to “Near-Infrared Spectroscopic Study
of the Interactions between Water and Acetone,” by Burneau and Corset Publication costs assisted by the Veterans Administration
Sir: Burneau and Corset’s studies’ of CC14-acetonewater mixtures in the medium and near-infrared spectral regions demonstrate the sequential formation of 1-1 and 1-2 water-acetone complexes as the mole fraction of acetone is increased. While their assignments are correct in the fundamental region, they are subject to certain doubts in the overtone region. The assignment of the 7163-crn-‘ band to ~(101)is in agreement with other studies.2 They do not consider the passibility of a v(200) band due to the bonded OH in the 1-1 complex while assigning the 7150-cm-l band to ~(002)of the free OH in the 1-1 complex and the 7078 cm-l band to ~(101)of the 1-2 complex. The shoulder at 7050 cm-l observed at moderate acetone concentrations moves toward higher frequencies and appears as a peak at 7078 cm-’ in pure acetone as solvent. The peak at 7078 Cm-’ (Similar to Figure 5 in our paper3) is broad and asymmetric and can be resolved into two Gaussian peaks-one at 7075 cm-’ and another at -6980 cm-1. This is obvious from Figure 5 in our Papers3 In the fundamental region, the 1-2 complex The Journal of Physical Chemistry, Vol. 76, No. 3,107%
(1) A. Burneau and J. Corset, J. Phys. Chem., 76, 449 (1972). (2) D. I?. Stevenson, ibid., 69, 2145 (1965). (3) W. C. McCabe, 8. Subramanian, and H. F. Fisher, ibid., 74, 4360 (1970). 43, 134 (1967). (4) W. A. P. Luck, Discuss. Faraday SOC., (5) T. F. Lin, S. D. Christian, and H. E. Affsprung, J. Phvs. Chem., 69, 2980 (1965); T. F. Lin, S.D. Christian, and H. E. Affsprung, ibid., 71, 1133 (1967). (6) J. D. Worley and I. M. Klote, J . Chem. Phys., 45, 2868 (1966).
VETERANSADMINISTRATION HOSPITAL KANSAS CITY,MISSOURI64128
S. SUBRAMANIAN
H. F. FISHER*
RECEIVED OCTOBER21, 1971
Bicipital Relaxation Phenomena Publication coats assisted by the National Institutes
of
Health
Sir: I n investigating the kinetics of metal-ligand reactions using the temperature-jump relaxation method, we have recently observed unusual behavior in the relaxation curves which does not appear to have been
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(1) (a) D. B. Rorabacher, Inorg. Chem., 5, 1891 (1966); (b) W. J. MacKellar and D. B. Rorabacher, J. Amer. Chem. ~ o c . ,93, 4379 (1971); (c) D. B. Rorabacher and C. A. Melendez-Cepeda, ibid., 93, 6071 (1971); (d) D. B. Rorabacher and R. B. Crue, Abstracts INOR-43,162nd National Meetingof the American Chemical Society, Washington, D. C., Sept., 1971; (e) F. R . Shu and D. B. Rorabacher, Inorg. Chem., accepted for publication.
