THE MOLECULAR-STRUCTURE OF N,N'-DIFORMOHYDRAZIDE FROM AB-INITIO STUDIES (MP2 AND DENSITY-FUNCTIONAL THEORY) AND FTIR MATRIX SPECTROSCOPY

The FTIR spectrum of N,N'-diformohydrazide isolated in argon and nitro gen matrices is presented and discussed in terms of normal modes predi cted by ab initio calculations, MP2/6-31G and BLYP/6-31G* methods are applied to calculate vibrational frequencies, IR intensities and isot opic shifts of different structures of the molecule. The number of abs orption bands and their frequencies for the isolated molecule differ s ignificantly from those of N,N'-diformohydrazide in the solid state. T he conformation of the undistorted molecule is different from the plan ar structure adopted by the molecule in the crystal and such a conform ation change is proposed as the reason for the spectral differences, A b initio calculations support this assignment and predict the vapour o f N,N'-diformohydrazide to be a mixture of conformers.