A. P. Grekov

The appearance of the NH group valence vibrations in the infrared spectra of carboxylic acid hydrazides

Fig. 1. The IR spec t r a of solutions in CCl4: I)CsHsCONHNH2; II) CdHsCSNHNH2; III) CdHsCSN(CH3)NH2; a) C = 0.001 mole / l i t e r , d = 1 0 a m ; b) C = 0.01 mo le / l i t e r , d = 5 cm. p r i m a r y and secondary amino groups, it might be expected that the band at 3450 em -1 would be split. Since no such spli t t ing was observed, the authors of [2] suggested that, for the Mnemat tca i Iy coupled vibra t ions , the N H N H 2 f r agmen t is wholly cha rac t e r i zed by two bands r a the r than three . In o r d e r to check the val idi ty of these different p roposa l s , it is of in te res t to study the changes which occur in the s p e c t r a of the hydraz tdes when the hydrogen a toms in the N H N H 2 group a re replaced . Definite conclusions can be drawn f r o m a compar i son of the s p e c t r a of the foilbwtng compounds: benzhydrazide (I), th iobenzhydraztde (II), ce-methyI th tobenzhydrazide (III)*