Dec. 20, 1955
NOTES
6507
TABLE I FORMATION CONSTANTS OF ( H z N C H ~ ) ~ C H O WITH H VARIOUS METALSIN 1.0 M KXOa SOLUTION Values for (H*SCH2)2CH2and (H~T\TCH~)ZC( CH3)1 included for comparison. log
H+, 0 " 30 50 O Ag++, 30' Co+', 30" Xi++, 0" 30" 50 O
Zn++, 30"
(H2NCHn)zCHOH Ki log
10.65 9.68 9.11 5.80 3.90 6.19 5.64 5.37 4.60
Kz 9.14 8.23 7.69 3.24 4.88 4.38 4.01 4.42
stants are those given by Carlson, McReynolds and Verhoek.6 The calculated constants are given in Table I.
1,3-Diamino-2-propanol is a somewhat weaker base than either 1,3-diaminopropane or 2,2-dimethyl-1,3-propanediamine. The complete agreement in the iV values for all three amines (except for Cu++) indicates that the -OH group is not active in coordination. The complexes of 1,3-diamino-2-propanol with Co++, Ni++ and Zn++ are less stable than those of 2,2-dimethyl-l,3-diaminopropane with the same ions. Similarly, the Ni++ complexes are less stable than those of 1,3-diaminopropane. The system Cu++-l,3-diamino-2-propanol is anomalous in that G reaches a maximum value of 1.5.
(HzNCHz)zC(CH3)z6 log K I log Kz
(HzNCHz)zCHz6 log
Ki 11.60 10.54 9.92
Kz 9.95 8.95 8.38
7.00
4.92
log
11.22 10.22 9.65 4.66 4.88 i.22 6.59 6.23 5.21
9.07 8.18 7.55 3.07 4.99 4.41 4.15 5.20
tion time to about 10 minutes. The original method gave yields from 35 to 45%. This method gives yields of from 45 to %yo.
Experimental Preparation of the trans Form.-A flask containing 3.8 ml. of I-propylenediamine (resolved by the method of Baumann6 as modified by Bailar and co-workers4 and further modified by Jonassen6) and 4.76 g. of CoC12.6HzO was immersed in an ice-bath. While swirling the solution in the reaction vessel 3 ml. of 30y0 HzOz was added cautiously. On removal from the ice-bath, 25 ml. of concd. HC1 (sp. gr. 1.18, 34y0 HC1) was added slowly. The resulting solution was concentrated to one-third of its original volume by passing a stream of air over it, keeping the temperature below 80". The green crystals formed, truns[Co-I-pn2Cl2] C1, were separated from the solution byofiltration, washed with ether and dried in an oven below 80 Conversion to the cis Form.-The dried crystals of the ( 5 ) C. A. Carlson, J P . McReynolds and F. H. Verhoek, THIS trans salt were dissolved in a minimum of water and the J O U R N A L , 67, 1334 (1945). solution carefully neutralized with dilute ( 1 :4) NH40H t o (6) G. B. Hares, W. C. Fernelius a n d B. E. Douglas, ibtd., aca PH of approximately 7. On evaporation of this solution cepted. on a steam-cone, purple cis-[Co-l-pnd&]Cl formed as a glassy solid. The extreme solubility of the compound in COLLEGE OF CHEMISTRY water and the fact that it must be converted to the cis form THEPENXSYLVAXIA STATEGNIVERSITY in a neutral solution seems to make the preparation as a STATECOLLEGE, PA. glassy solid imperative. Solubility studies made in this Laboratory have failed to yield any solvent from which it may be crystallized. This entire preparation was carried The Preparation of cis- and of frans-Dichloro-bisout in less than 4 hours.
I-propylenediaminecobalt(II1) Chloride1b2
BY SR. MARY MARTINETTE,B.V.M., JOAN BUSCHAND MILDAGULBINSKAS JULY 6, 1955 RECEIVED
.
(5) G. Baumann, Bev., 28, 1180 (1895). (6) H. B. Jonassen, Thesis, University of Illinois, 19-16
DEPARTMENT OF CHEMISTRY FOR WOMEN MUNDELEIN COLLEGE ILLINOIS CHICAGO,
The preparation of cis- and of trans-dichlorobis-l-propylenediaminecobalt( 111) chloride was first reported by Werner and F r o h l i ~ h . ~This method Basic Equilibrium Constants of Nitroguanidine and was later modified by Bailar and c o - ~ o r k e r s . ~ Nitroaminoguanidine We wish to report a semi-micro preparation which E DE VRIESA N D E ST. CLAIR is a further modification of the original procedure. BY LILAM HALL,J O H N GAXTZ By making a careful study of the acidity require26, 1955 RECEIVED SEPTEMBER ments and of the procedure for oxidizing cobalt(I1) to cobalt(II1) the time required has been greatly The basic equilibrium constants of nitroguanidine diminished and the product is obtained without dif- and nitroaminoguanidine are extremely small. ficulty. The original method often yielded a prod- Consequently accurate determination of these uct which could not readily be converted from trans values has not been possible by the usual titrimetric to cis, possibly because of a residual acid condition; procedures. I n connection with a study of the consequently the product was of questionable pu- reactions of nitroguanidine in strongly acidic solurity. The ready conversion from trans to cis has tions,' i t was observed that the small peak a t been considered a good index of purity. Use of 220-225 mp increased with increasing acidity. 30y0 H202cuts down the original 16 hours of aera- The family of curves obtained showed a sharp isosbestic point a t 240 mp between the minor (1) From t h e B.S. theses of Misses Joan Busch and Milda Gulbinskas. (225 mp) and major (265 mp) absorption peaks, (2) Aided by a grant from Research Corporation. Fig. 1. The 265 mw peak did not shift appreciably
(3) A. Werner and A . Frohlich, Ber., 40, 2225 (1907). ( 4 ) J . C. Bailar, Jr., C. A. Stiegman, J . H. Balthis, J r . , and E. H. Huffman, THISJ O U R N A L , 61, 2402 (1939).
(1) W U' Brandt, J E De Vnes and E S t C Gantz, A n d Ckem 27. 302 (1955)
