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The molecular and crystal structures of chlorine-, bromine-, and nitro-substituted chromium(III) acetylacetonate are determined. Connecting the substituent to the central atom does not change bond lengths and valence angles in metal chelate rings. Studied chromium complexes are characterized by greater intermolecular interactions compared with analogous metal acetylacetonates. In some cases, intermolecular interactions increase the bend of chelate rings along the O⋯O line. Substituents do not interact with chromium ions of neighboring molecules because metal is blocked by three ligands. [ABSTRACT FROM AUTHOR]

Abstract Molecular and crystal structure of the complexes F 2 B(AcAcX) (X = I, OCOCH 3 , 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 = OCOCH 3 , 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 O 2 BF 2 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. Graphical abstract Image 1 Highlights • 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: νCC α vs electrophilicity index and ΔνBF vs melting points. [ABSTRACT FROM AUTHOR]

[Display omitted] • Two isomers of boron difluoride naphthaloylacetonates were synthesized. • Interrelation between crystal structure and luminescent properties has been revealed. • The complexes exhibited fluorescence, delay fluorescence and phosphorescence. • The role of the inversion of S 1 and T 2 levels in enhancing delay fluorescence is revealed. A comparative study of the luminescence properties of solutions and crystals of two isomers: boron difluoride 1-(1′-naphthyl)butanedionate-1,3 (α-NAcBF 2) and 1-(2′-naphthyl)butanedionate-1,3 (β-NAcBF 2) has been performed. An interrelation between the molecular and crystal structure of the studied complexes and their luminescence properties has been revealed. In the α-NAcBF 2 molecule, the plane of the naphthyl group was turned by 34.26° relatively to the chelate cycle, while the β-NAcBF 2 molecule was planar. The difference in the luminescence properties of the crystals of α-NAcBF 2 (452 nm) and β-NAcBF 2 (537 nm) was related to different abilities to form excimers. In β-NAcBF 2 crystals, J-aggregates consisted of dimers of antiparallel molecules comprising excimer traps. For the crystals and solutions of α-NAcBF 2 at 77 K, in addition to phosphorescence, the delayed fluorescence was observed. In case of β-NAcBF 2 , the delayed fluorescence was detected only for crystals, whereas the phosphorescence – for both crystals and solutions. [ABSTRACT FROM AUTHOR]