The interaction of NH3 and CHCl3 molecules in CCl4 solution from infra-red spectra

Research notes

~c~~~e~~s-The author is indebted to Prof. D, F. HORNIGfor a ~scu~ion of these spectra, and to British Nylon Spinners Ltd., for permission to publish this work. c. G.

Research Dept., British Nylon Spinners Ltd. Pontypool, Mon., W&e

CANNON

References [l] BECKERE. D. and PIMENTEL G. C. J. Chem. Phys. 1956 25 224-28. [2] VEDDERW. Paper presented at European Molecular Spectroscopy Meeting, Freiburg im Breisgau, July 1957. [3] REDXNU F. P. and HORNIGD. F. J. Chem. Phys. 1954 22 1926-28. [4] REDINGF. P. and HOBNIGD. F. J. C&em. Php. 1951 19 594. [5] CANNON C. G. ~~ec~~oc~~rn.Acta 1958 10 417. D. vau [S] RERZBEROG. &z&a-red and ~~~~ Spectra of Pol~atom~c ~~o~~~es pp. 295-97. Nostrand, New York 1945. [7] CUXMINC;C. and WSXSH H. L. J. Chem. Phys. 1953 21 1119.

The interaction of NH, and

CHC&

molecules in

CCI,

solution from infra-red spectra

(Received 29 August 1957)

THE interactions of CDCI, with a variety of solvent molecules have been studied by LORD, et al. [l] and HUGGINS and PIMENTEL[2] by recording frequency and intensity changes of the GD stretching band in the infra-red spectra. &ICK has recorded the CH frequency shifts of haloforms interacting with triethylamine in tetrachlorethylene solutions [3]. This note records the C-H frequency shifts of chloroform on interaction with ammonia in dilute solution in carbon tetrachloride.

Results The spectra were recorded with a Perkin-Elmer 12C equipped with LIF prism and slit drive [4]. The frequencies observed are collected in Table 1. The NH, concentrations were determined by titration (Slav) and the CHCI, concentrations were obtained by volumetric addition (v/v). The rCH frequency of chloroform shows a lower frequency component in the presence of ammonia. At different relative molar concentrat,ions of NH, and CHCI, (9 : 1 and 3 : 1 approx.) the relative intensities of these two frequencies change(optica1 densities,O.D., given in Table 1) showing that the lower frequency corresponds to the complex formed by the specific interaction of NH, and CHCl, molecules which produces a frequency shift of 31 cm-l. This shift can be compared with Avon of 36 cm-l in pyridine (1) and Av,, of 110 cm-1 with triethylamine [3]. Remembering the mass difference (H, D) these shifts are in the order of basicities of the nitrogen atoms. No splitting or signi~cant frequency shifts were detected for any of the ND3 bands

429

Research notes Table 1. NH and CH frequencies of chloroform/ammonia Frequencies cm-l Assignments 0.2%

NH,

v3 +

14

?A f

v3

Vl + v2 +

v2 2v4

v3

2”;, CHCl, VCH“free” VCH“associated

NH,

NH, + 06% CHCl,

0.13%

4435 4325

3419 3315 3232

3417 3315 3228

in Ccl, solutions

T

I

0.13% NH, + 0.15% CHCI,

I _/-

3417 3315 3214

4217 3016 2985

0.5 y. CHCl,

_

I-

5020

5025 4438 4330 4205

mixtures in carbon tetrachloride

4215 O.D. 0.495 0.125

3017 2985

O.D. 0.145 0.025

3017 (O.D. 0.490) -

-CH frequency shift

= 31 cm-l

= 32 cm-l _I-

Molar ratio NH3: CHCl

2.75

:1

9.2 : 1

observed, so the interaction must be solely between the lone pair electrons of the nitrogen and the CH bond of the chloroform. Thanks are due to British Nylon Spinners Ltd., for permission to publish this note.

Research Dept., British Nylon Spinners Ltd. Pontypool, Mon., Wales

C. G. CAXNON

References [l] [2] [3] [4]

LORD R. C., NOLIN B. and STIDHAM H. D. J. Amer. HUGGINS C. M. and PIMENTEL G. C. J. Chem. Phys. GLICE R. E. Chem. & Ind. (Rev.) 1956 No. 19 413. CANNON C. G. J. Sci. Instrum. 1952 29 50.

Chem. Sot. 1955 77 1365. 1955 23 896-98.