R ~ KESWANI I AND HENRY FXEISER
1'18 i CO\lK'IB'LTIOY
FXOM THE L ) E P A K I U E X T OF
Vol. 71
CHEMISTR\ vNIVERSIrT U P PITTSBURGH]
Electric Moments and Structure of Substituted Thiophenes. I. Certain Halogenated Derivatives1 R Y RAJXKESWAW AXD HENRY FREISER
Interest in the structure 01thiophene and in the quency Audio Oscillator Model 179A whose influence of substituents upon that structure lias variable frequency oscillator circuit was modified prompted the initiation oi a prograin for the de- by the replacement of some of the original capacitermination of the dipole Inonients of substituted tance by a General Radio Precision Condenser , thiophenes. h i d e from thiopheiie2 itself and 2- -,i--. F and a dielectric cell in parallel. The measnitrothiophene,a no measurements of dipole mo- urement procedure has been reported elsewhere.' inents of members of this interesting heterocyclic The cell, similar in design to that previously refamily have been reported. The measurement oi ported,' was constructed of stainless steel and thiophene and 2-nitrothiophene have been re- Teflon. The densities of the liquids and solutions peated here for purposes of comparison. The were measured in flask-type pycnometers of 20 work reported here on certain of the halogenated ml. and 100 rnl. capacities, respectively, in a manthiophenes represents the first phase nf the pro- ner similar t o that previously reported,s with an estimated accuracy better than one part in 100, w but apprrciahlr ‘I
