CORRESPONDENCE 1805
Vol. 3, No. 22, December, 1964 tion of Kll from il than what the wave lengths 370-400 mp offered. Acknowledgment.-This work was supported by the United States Atomic Energy Commission through contract AT( 11-1)-687. DEPARTMENT OF CHEMISTRY OHIOUNIVERSITY
JAMES
YINGPRIT TONG
ATHENS, OHIO
RECEIVED JULY 6, 1964
600
Infrared Spectra and Force Constants of Ammine Complexes
200
100
a real one, although it is very weak.4 The metalnitrogen stretching bands for Co(III), Pt(II), and Pd(11) are very weak, that for Cr(II1) moderately weak, that for Cu(I1) medium, and those for Ni(I1) and Co(I1) fairly strong. The values of the metal-nitrogen force constants vary in the order Pt(I1) > Pd(I1) > Co(II1) > Cr(II1) > Cu(I1) > Ni(I1) > Co(I1). The intensity for the metal-nitrogen stretching vibrations increases as the value of the force constants decreases. This trend is plausible, because the ionic character of the metalnitrogen bond seems to increase as the force constant decreases, causing a larger transition moment ( b p / d r ) .
Watt and Klett suggested that the nature of Co-N stretching and deformation modes of cobalt-ammine complex ions remains to be reso1ved.l Recently we have extensively measured the far-infrared spectra down to 80 cm. -l for various metal-ammine complexes. We have made a normal coordinate analysis of the infraredactive species where the vibrations in the NH3 ligand as well as those for the skeletal part are taken into consideration and obtained the force constants associated with the metal-ligand bonds and those for the ligand vibration.2
TABLE I OBSERVEDAND CALCULATED FREQUENCIES (CM.-~)
Calcd. E, Obsd. Calcd. E, Obsd. Calcd. Flu Obsd. Calcd. Flu Obsd. Calcd. FI, Obsd.
400 300 Cm. -1.
Fig. 1.-The far-infrared spectra of trans-[CoClz(NH~)ajCl(upper curve) and tmns-[CoCl~(en)~]Br (lower curve).
Sir :
VI
500
Y2
OF
Y8
METAL-AMMINE COMPLEX IONS
Y1
us
YE
Y7
K(MN), mdynes/
HWNM), mdynes/
v(NH)a
U(NH)S
G(NH8)d
G(NHs)e
Q(NH&
v(MN)
G(NMN)
A.
A.
3231 3236 3240 3268 3240 3240 2396
3155 3156 3164 3142 3164 3170 2265
1619
1344 1325 1304 1285 1323 1325 1009 1016 1292 1310
846 842 7 74 797 830 820 661 665 759 745
509 510 493 49 1 501 503 454
295 297 296 295 328 325 291 310 267
1.92
0.180
1.71
0.1,50
1.05
0.169
1.05
0.169
0.94
0.123
1251
708 713
419 420
249 ~ 2 5 0
0.84
0.107
1197 1175 1171 1160
672 678 625 634
335 330 323 318
214 -215 184
0.34
0.095
0.33
0.065
2450 3268 3260
Calcd. E, Obsd.
3191 3205 (3140) 3310 3231 3270
Calcd. Flu Obsd. Calcd. Flu Obsd.
3393 3310 3370 b 3338 3258 3330 3250
1563 1613 1601 1615 -1600 1165 1155 1612 1600 1610 1610
);;{
1606 1610 1605 1605
...
474 470
...
...
The results are summarized in Table I. With regard to [CO(NH&]~+we reported three bands, a t 503, 492(?), and 464 cm.-l, in the region from 500 to 450 cm.-l in the previous paper.3 However, it was found that the band a t 464 cm.-l is due to the stray light and is not a real band.4 The band a t 503 cm.-' is definitely
We have made the calculation of the normal modes of vibration (the elements of the L-matrix) and the per cent potential energy distributions among the symmetry coordinates (PED, the diagonal elements of the matrix LFLA-I, FiiLih2/X). The results for the [Co("&I3+ ion are given in Table I1 as an example.
(1) G. W. W a t t and D. S Klett, Inorg. Chem , 8, 782 (1964). (2) I. Nakagawa and T. Shimanouchi Spectrochim. Acta, t o be published; J. Hiraishi, I. Nakagawa, a n d T. Shimanouchi, zbzd , t o be published. (3) T. Shimanouchi and I. Nakagawa, Spectrochzm. Acta, 18, 89 (1982).
(4) I n [CoX(NHdalZ+ a n d tvaws-[CoXz(NHs)al+ ions, where one or two NH3 ligands are substituted b y halogens, t h e bands observed in t h e region 500-450 cm -1 enhance their intensities, and these bands are primarily assigned t o metal-ligand stretching vibrations 2 3 For [Co(NHs)e]Brs we have made very careful measurements using two different instruments and we could not regard t h e band a t 464 ern.-' as a real band,
1806 BOOKREVIEW
Inorganic Chemistry
The results for the other metals are more or less alike, but these are not given to save space. Table I1 shows
TABLE 111 ORSERVED AUD CALCULATED FREQUESCIES OF [CoCle( [Dshl
TABLEI1 PER CENTPOTENTIAL EXERGY DISTRIBUTIONS (PED) [Co(SH&] 3 - (FI,,SPECIES)~ Symmetry coordinates
SINHs asym. str. S2NHa sym. str. Sa NH3 deg def. S4 XH3 sym. def. S, NH3 rocking
Y2
FOR
Azu
v3 Y4
YI
YZ
ua
Y4
Yb
YG
Yl
v5
100 100 94
+
15-
loo+
3190+ 5M-h’ str. 1+ 71+ S7 SiMS def. 729a Only the relative signs for the L-matrix are given. s 6
Y1
2+ 28+ 64+
that the ligand vibrations (“3 stretching and deformation vibrations) are pure vibrational modes corresponding to the symmetry coordinates. The Co-N stretching and NCoN deformation modes ( V 6 and v7) are coupled with each other moderately but they are not coupled with the ligand vibrations. When we look a t the results of Table I , nSH3 rocking frequencies change considerably with metal ions. This arises mainly from the change of the angle deformation force constants H(HNM), which are also listed in Table I, but not from the coupling of NH3 rocking and M-N stretching modes. With regard to the Co-X stretching mode of the halogenoammine complexes, we should revise our previous assignment, as Watt and Klett pointed out. The far-infrared spectrum of [CoC12(NH3)~] + is shown in Fig. 1, compared with [ C ~ C l ~ ( e n ) ~ ]By + . this comparison we can reasonably assign the sharp band a t 353 ern.-' to the Co-C1 stretching mode. The observed and calculated frequencies are shown in Table 111. The broad strong band a t 290 cm.-l of similar feature to the 325 cm.-l band of [Co(XH3)6j3+is assigned to NCoN deformation vibration of E, species. The calculated value of this vibration by using the same value
Calcd.
Obsd.
3239 1616 829 347 186
3253 1585 815 333 186
3240 3164 1617 1339 833 483 311 127
3252 3161 1385 1300 815 501 290 (167)
Vib mode
Y(XH),
a( SH3)d 6( SH3
4MX) 6(KMX)
of the force constant H(N1LIN) is in good agreement with the observed value. In [ C ~ C l ~ ( e n ) ~ the ] +broad , band near 290 cm.-I is assigned to the skeletal deformation mode similar to that for [CoC12(KHa)a]+,which is also supported by a normal coordinate analysis.5 If we assign the 290 cm.-l band to a Co-Cl stretching mode, we should assign the 353 cm.-l band to a NCoN deformation mode. This is unreasonable, because the band feature is quite different from the NCoK vibration band for [Co(“3)6I3+, and also the observed frequency deviates from the calculated one. K(Co-N) is assumed to be the same as in [c0(”3)6]~+ and K(Co-C1) is calculated to be .OO mdynellA. -4 normal coordinate analysis has also been done for [ C O X ( ; \ T H ~ ) ~ ]For ~+. [CoC1(NH3)5]2+, the 457 cm.-l band is assigned to the antiphase (Co-N, Co-C1) stretching mode of A41 species and the doublet (487 and 479 cm.-l) is assigned to the Co-N Stretching mode of E species. ( 5 ) I. Nakagawa and T. Shimanouchi, t o be published (Eighth International Conference o n Coordinat;on Chemistry, Vienna, 1961).
DEPARTMENT O F CHEMISTRY TAKEHIKO SIIIMANOUCIII FACULTY O F SCIENCE TCRIRO P\-AKAC,AIVA USIVERSITYOF TOKYO HOSOGO. TOKYO, JAPAS RECEIVED JULY 9, 1964
Book Review Organoboron Chemistry. Volume 1. Boron-Oxygen and BoronSulfur Compounds. By HOWARDSTEINBERG. Interscience Publishers, John Wiley and Sons, Inc., New York, N. Y. 1964. 950 pp. 16 X 23.5 cm. Price, $33. xxxii
+
This book, which is one of three volumes planned by Dr. Steinberg, deals with organic compounds having boron-oxygen and boron-sulfur linkages. The next two volumes will deal with boron-nitrogen, boron-phosphorus, and boron-carbon compounds. The arrangement of material follows a detailed outline; the same outline IS given in the Table of Contents (which alone encompasses 24 pages!). The research results reported in over a thousand publications are mentioned. There are 21 chapters and each is ended with a list of references and of compounds (including what physical properties are available). For example, Chapter 15, which deals with “Coordination Compounds Derived
from Polyhydric Alcohols and Phenols,” has about 56 pages of text, 45 pages nf tables, and 169 references. This book clearly demonstrates the large amount of available qualitative data on boron-oxygen compounds containing organic groups. Unfortunately the available amount of quantitative data, such as structures, rates, and equilibrium constants, lags far behind. The material in Chapter 21 (“Hydrolytic Stability”) exemplifies the type of data that we need more of. The author has done a monumental (and, I believe, successful) job in bringing together the data 011 these compounds into one volume, and the resulting encyclopedic nature is useful to thosc interested in this field. Xevertheless, the strengths of the book are also the weaknesses; for example, several types of synthetic methods for the preparation of a class of compounds are listed, yet rarely does the reader get any feel for the preferred method.
