DIPOLEMOMENT MEASUREMENTS OF TETRAZOLE DERIVATIVES
Scpt. 5 , 1956
9s and S9 kcal./niole, respectively. Their calculation was based on the incorrect assumption that the CO bond energy is the same in Fe(C0)6 as in Ni(C0)4. The Raman spectrum of Fe(C0)5 indicates t h a t this assumption is not justified. Also, they had no effective means of estimating the %O bond energy from that of carbon monoxide. The Fe-C and Ni-C bond energies calculated here are of the same order of magnitude as bond energies calculated for Sn-C and Pb-C, indicating that the Fe-C and Ni-C bonds must have a bond order only slightly larger than 1.16 This result is consistent with the values for the Sn-C,Pb-C, Zn-C and
4197
Cd-C bond stretching force constants which have values of 2.37, 1.94, 2.39 and 2.05 X lo7 dynes,’ cm., respectively. l 8 hi^^^ ADDED I N PROOF.-L$”? have recently made detailed calculations of the valence force symmetry coordinates (VFSC) and valence force coordinates (VFC) for Fe(CO)s using the Wilson F G technique and the above assignment of frequencies. We calculate for the axial and equatorial Fe-C bond stretching VFC the values 3.06 X 105 and 3.29 X lo5 dynes/cm, respectively.
This work was supported in part by the U. S . Atomic Energy Commission. (18) R. K. Sheline, J. Chern. Phrs., 1 5 , 602 COLLEGEPARK,MD.
(1‘35‘3).
u. s. NAVALORDNANCE TESTS T A T I O N ] Dipole Moment Measurements of Tetrazole Derivatives [COSTRIBETION FROM
13l’
h1,UXTIN 13. KAUFMAN, FRED31. ERNSBERGER ,4ND
II‘ILLIAM
s. MCEWAN
RECEIVEDDECEMBER 27, 1955 Uipolc rnoiiients have been measured for a variety of tetrazole derivatives. inents are not suitable for recognizing “meso-ionic” compounds.
It has been established that such nicdwrc-
Dielectric Constants.-These mere measnred with a Leeds Introduction and Worthrup Company capacitance and conductance bridge Henry, Finnegan and Lieber‘ recently reported using No. 1553 shielded ratio box. The dielectric constant a cell consisting of three concentric cylinders of brass tubing the preparation of 1,3-dimethyl-5-i:ninotetrazole, was similar in design to the measuring condenser of Smyth cyclic “meso-ionic“ compound. It was antici- and Morgan.6 The assembly was sealed into an annular pated2 that the reaction of 2-methyl-3-aminotetra- “Pyrex” glass cylindrical vessel. The annular space rezole with methyl benzenesulfonate, according to duced the quantity of solution required and aided in the the procedure of Herbst, Roberts and H a r ~ i l l , ~circulation of the thermostated kerosene. The apparatus calibrated with benzene, the dielectric constant of which would result in the formation of the 1,2-dimethyl was was taken to be 2.2750 a t 25O.6 derivative. However, a preliminary X-ray analySpecific volumes were determined with a 25-ml. “Weld” sis of the hydrobromide salt of the resultant com- specific gravity bottle with which specific gravities can be pound? and a modified three-dimensional Fourier determined t o within 0.001 7c. Refractive indices were measured with a “Spencer Abbe” synthesis by Bryden? demonstrated unambiguously refractometer. The pure benzene was taken to havc a that the compound was the cyclic “meso-ionic” standard refractive index of 1.5002.
1,5-dimethy1-5-iminotetrazole. A complete X-ray analysis will lead to an accu-
rate structure; however, it is not generally applicable t o all compounds. The purpose of this investigation was to see what information about the structure of tetrazoles could be obtained from dipole moment measurements and whether it was possible to recognize “meso-ionic” compounds by such measurements. Experimental Materials and Methods.-Mallinckrodt, analytical reagent grade benzene was purified by crystallizing twice and then fractiimally distilling after standing several days over freshly cut and ribboned sodium. All was rejected but the center cut which was redistilled in the same nianner before use. The spccific volume parameter for the solvent was obtained for each run from a least-squares examination of the specific volume, weight fraction data and was found to be cbnstant to rt0.02y~: Tetrazo1es.-These were obtained, fairly pure, from Drs. Iiltc,n
1 ) Ollis,
V
13 l ' ( ~ > l i i .1 , A I ; c t r l t r o ~I
(kcal./ml.)
(kcal./m.)
25.75 21 ,10
- 430. 1 -430.8
The vapor pressure data of tetrazole seem to intlicate that its dipole moment in benzene should be lower than the dioxane value of Jensen and Friediger. It is also apparent from melting point data that intramolecular bonding to ring nitrogens by amino hydrogen is hindered by alkylating the amine if another allyl is in the one position. Acknowledgments.-We wish to thank Drs. I
