Structure and vibrational spectra of iodo-, acetoxy- and thiocyanato-substituted acetylacetonates of boron difluoride

• Published in: Journal of molecular structure 2019-01, Vol.1175, p.512-523
• Main Authors: Kuarton, Larisa A., Ryabchenko, Olga B., Svistunova, Irina V., Bukvetskii, Boris V.
• Format: Article
• Language: English
• Subjects: DFT calculations; Difluoroboron acetylacetonates; Frequency shift correlations; Intermolecular interactions; IR and Raman spectra; X-ray diffraction
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2018.07.100

Molecular and crystal structure of the complexes F2B(AcAcX) (X = I, OCOCH3, SCN) have been studied by XRD method. All the compounds manifest noticeable distortions of the chelate ring due to intermolecular interactions of fluorine atoms with atoms of the α-substituent as well as with carbon atoms of the chelate ring. First detailed assignment of FT-IR spectra registered in crystalline state and in solution and FT-Raman spectra in crystalline state of acetoxy- and thiocyanato-substituted complexes has been carried out basing on DFT/B3LYP calculations in 6-311G (d, p) basis set. Raman spectra of the complexes with X = OCOCH3, SCN have been obtained for the first time including their low frequency region, previously unobserved for these compounds. All spectral results have been discussed in comparison with those for previously reported IR spectrum of the iodo-substituted complex. Observed in vibrational spectra evidence of intermolecular interactions is consistent with XRD data. Both XRD and spectral results prove that intermolecular interactions (IMI) involving O2BF2 moiety play the key role in the crystal packing of these compounds and govern their related properties in crystalline state. Revealed in this study correlations may be suitable in subsequent studies of physical and chemical properties of boron difluoride β-diketonates. [Display omitted] •Structure of α-substituted boron difluoride acetylacetonates is determined by XRD.•DFT calculations of the complexes are performed.•Detailed assignment of bands in IR and Raman spectra of two complexes is done.•Marker bands that demonstrate evidence of intermolecular interactions are revealed.•Correlations are found: νCCα vs electrophilicity index and ΔνBF vs melting points.