Ethylenediammonium dication: H-bonded complexes with terephthalate, chloroacetate, phosphite, selenite and sulfamate anions. Detailed vibrational spectroscopic and theoretical studies of ethylenediammonium terephthalate

Crystalline complexes between ethylenediammonium dication and terephthalate, chloroacetate, phosphite, selenite and sulfamate anions were obtained by slow evaporation from water solution method. Room temperature powder infrared and Raman measurements were carried out. For ethylenediammonium terephthalate theoretical calculations of structure were performed by two ways: ab-initio HF and semiempirical PM3. In this case the PM3 method gave more accurate structure (closer to X-ray results). The additional PM3 calculations of vibrational spectra were performed. On the basis theoretical approach and earlier vibrational studies of similar compounds the vibrational assignments for observed bands have been proposed. All compounds were checked for second harmonic generation (SHG).

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Spectroscopic properties of different forms of ethylenediamine specie are presented. ► For ethylenediammonium terephthalate spectra correlate satisfactorily with structure. ► Bands corresponding to main functional groups were assigned. ► For ethylenediammonium terephthalate ab-initio HF and PM3 formalism were applied. ► All studied compounds were checked for second harmonic generation (SHG).