VIBRATIONAL-SPECTRA OF THE SOLID-SOLUTION OF (PIPERAZINE-PINACOL) HEXAHYDRATE AND POLARONS

Raman and infrared spectra of crystals obtained from an aquaeous solut ion of piperazine and pinacol with an arbitrary molar ratio were obser ved and confirm the formation of a solid solution of (piperazine-pinac ol) hexahydrate, for which the infrared and Raman bands due to piperaz ine molecules change as tbe molar fraction of piperazine, x, changes. The Raman spectra of the deuterated system with x = 0.80 were also obs erved in the temperature range 296-25 K. One of two N-D stretches, the lower wavenumber one, increased in intensity as the temperature decre ases and was assigned to polarons. It was found that the Raman intensi ty of the polarons is stronger in the solid solution than the parent c ompound, which can be qualitatively explained in terms of the differen ce in structure between them. (C) 1997 John Wiley & Sons, Ltd.