Gauche and trans ethylenediammonium in the structures of ethylenediammonium tetrafluoroborate and tetrafluoroborate‑fluoride crystalsVakulka, Andrii (Avtor) Goreshnik, Evgeny A. (Avtor) ethylenediammoniumRaman spectrumtetrafluoroboratefluoridecrystal structureIR spectrumThe possible stereochemical conformations of the isolated ethylenediammonium dication were discussed, along with an assessment of their relative stabilities. Crystals of ethylenediammonium tetrafluoroborate-fluoride and tetrafluoroborate salts were prepared and structurally characterised. The crystal packing and hydrogen bonding interactions involving the ethylenediammonium dication were also described and analysed. In the structure of [enH$_2$](BF$_4$)F, the ethylenediammonium dication adopts a superposition of left-handed and right-handed C$_2$-symmetrical gauche (synclinal) conformations, with an NCCN torsion angle of ±75.49(10)°. These conformers form a cyclic R$^1_2$(7) [enH$_2$]F$^+$ fragment through hydrogen bonding with the fluoride anion. Three such R$^1_2$(7) [enH$_2$]F$^+$ fragments, along with a fluoride anion from a fourth [enH$_2$]F$^+$ unit, associate into a more complex R$^4_8$(16) ring motif within the hydrogen-bonded network of [enH$_2$](BF$_4$)F. In the [enH$_2$](BF$_4$)$_2$ salt, the ethylenediammonium dications adopt a trans configuration, corresponding to C$_{2h}$ point group symmetry. Raman and IR spectra were recorded and tentatively interpreted. A clear spectroscopic distinction between the trans and gauche conformations of the enH$^{2+}_2$ dication was observed and discussed.20262026-01-30 15:05:37Članek v reviji178849UDK: 54ISSN pri članku: 1572-9001DOI: 10.1007/s11224-025-02579-3COBISS_ID: 245833987sl