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The interaction of sulfenyl- and selenylchloride derivatives of boron difluoride acetylacetonate with ketones, diketones and other dicarbonyl compounds was investigated. In the majority of cases the expected products of substitution of hydrogen atom with γ-hio(selen)acetylacetonate group were obtained. The products with two chelate groups were obtained using the lack of ketone. The unusual interaction of selenylchloride with acetylacetone and acetoacetic ether was revealed. Derivatives of acetylacetone with ketone groups at the central sulfur atom were obtained by soft hydrolysis of boron complexes. [ABSTRACT FROM PUBLISHER]

The addition reaction of sulfenyl chlorides of metal acetylacetonates to vinyl-, allyl-, and cyclohexenyl-containing silanes has been studied to form silicon containing chelates of chromium(III), aluminum(III), and cobalt(III). The yields and stability of the chelates depend on the nature of the alkenyl groups and decrease in the order cyclohexeny > vinyl > allyl. The decomposition leads to elimination of chlorosilane, which depends on the stability of the silicon-carbon bond in the obtained chelates. The thermal decomposition of the monomeric chelates proceeds by elimination of chlorosilane and oxidation of the acetylacetonate group. The thermal stability decreases in the order Al > Cr > Co for all compounds, depending on the ease of conversion into the other oxidation states and on the ability of the metal to catalyze the oxidative processes. The aluminum-containing polymers have chelating properties after acidic hydrolysis. [ABSTRACT FROM AUTHOR]

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]

Modeling of cationic and excited states of boron difluoride acetylacetonate and eight of its γ-substituted derivatives was carried out using the methods of outer-valence Green's functions (OVGF), algebraic-diagrammatic construction for the polarization propagator of the second order (ADC(2)), coupled clusters with single and double excitations (EOM-CCSD), and time-dependent density functional theory (TDDFT/CAMB3LYP). Comparison of the calculated data with the absorption spectra made it possible to determine the influence of functional groups on the energies of electronic transitions and the nature of the absorption spectrum bands. Addition of the substituent SPh causes a decrease in the energy gap between the levels of the highest occupied and lowest vacant molecular orbitals, which determine the bathochromic shift of the long-wavelength band in the absorption spectrum relative to the other studied complexes. In the complexes containing Cl, Br, SCN, SEt, SPh and OS(O) 2 Ph groups in the γ-position, it was found that the highest occupied molecular orbitals are localized mainly on the substituents, and the lowest vacant molecular orbital corresponds to the chelate orbital π 4 , which determines the presence of transitions with charge transfer. It was shown that the calculated energies of excited states according to the ADC(2) method, in comparison with EOM-CCSD and TDDFT/CAMB3LYP, can be correlated with maxima of the experimental absorption spectra for the lowest average shift (0.27 eV). Image 1 • Nine boron difluoride β-diketonates were studied. • Complexes were studied by means of absorption spectroscopy. • The calculations were carried out using the Green's function and EOM-CCSD methods. • The experimental results were interpreted using quantum chemical computations. [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]

Context: This paper presents the results of the study of the electronic structure and cationic and excited states of three spiroborate complexes (2-acetylacetonato-1,3,2-benzodioxaborol, its NH- and NMe-derivatives) and three corresponding ligands (acetylacetone, 4-aminopent-3-en-2-one, and 4-methylaminopent-3-en-2-one). Materials based on spiroborates are used in medicine, for example, as a drug carrier. In industry, spiroborate anions are used in ionic liquids and as alternative high performance lubricants. Analysis of experimental and calculated data allowed determining the influence of functional groups on the parameters of the electronic structure and energy of electronic transitions. Compared to acetylacetone and its NH- and NMe-derivatives, the upper filled molecular orbitals of the corresponding spiroborates are stabilized at 0.4–1.7 eV, which is due to the positive charge of the ligand due to the acceptor properties of the dioxyphenylene fragment. Among the studied compounds, when replacing the oxygen atom in the α-position with the NH- or NMe-group, a bathochromic shift of intense bands in the absorption spectra is observed, since the energy intervals between the orbitals of the π3 and π4 ligand are reduced. In addition, in a number of spiroborates, the violation of C2v symmetry when replacing an oxygen atom leads to the appearance of a low-intensity maximum in the long-wave part of the absorption spectrum, due to the π2X → π4 transition. Method: Complexes were studied by photoelectron spectroscopy, absorption spectroscopy, and high-level ab initio quantum chemical computations, including the algebraic diagrammatic construction method for the polarization propagator of the second order (ADC(2)), the outer-valence Green's function (OVGF), the density functional theory (DFT), the time-dependent density functional theory (TDDFT) and the domain-based local pair natural orbital (EOM-DLPNO) methods. X-ray photoelectronic spectra of two spiroborates in the condensed state were measured using a two-chamber high-vacuum system MXPS XP (Omicron, Germany). UV–visible absorption spectra were recorded using a spectrophotometer 2550 (Shimadzu-UV, Japan). The geometry of all studied compounds was optimized by the DFT/B3LYP/Def2-SVP method. The energy of electron levels in the S0 state and the distribution of electron density at each MO were obtained by the DFT/CAMB3LYP/cc-pVDZ method. The energies of excited states were obtained by the TDDFT/CAMB3LYP/cc-pVDZ, ADC(2)/cc-pVDZ and EOM-DLPNO/cc-pVDZ methods. All DFT and TDDFT calculations were carried out in the GAMESS (US) software computing package. ADC(2) calculations of excited states were performed using the Orca 4.0.1 software package. EOM-DLPNO and OVGF calculations were carried out in the Gaussian 16 software package. [ABSTRACT FROM AUTHOR]

• Raman spectra of the F2B(AcAcX) with X= = H, Cl, Br, I were measured. • DFT calculations of the dimer and tetramer models remarkably fit experiment. • Combined investigation of non-covalent interactions in crystalline was performed. • Vibrational coupling νBF 2 +δC α H is essential for the band assignment and correlations. DFT calculations were carried out for two dimer forms and tetramers to model equatorial and axial noncovalent intermolecular interactions in the crystalline samples of F 2 B(AcAcX), where X = H, Cl, Br, I. Vibrational frequency shifts for dimer and tetramer models in reference to their monomer frequency values were analyzed in terms of their correlation with calculated energetic characteristics and experimental spectral and geometrical features. The role of intermolecular vibrational coupling in the νBF 2 range of the parent compound was shown. RDG plots and NCI isosurfaces in combination with vibrational spectra were applied to discriminate and describe different kinds of molecular interactions in the crystalline state of the compounds. In particular, halogen bonding and van der Waals bonds were revealed. Image, graphical abstract [ABSTRACT FROM AUTHOR]

[Display omitted] • Curcuminoids of boron difluoride have been synthesized. • Complexes studied by luminescence spectroscopy and DFT modeling. • Introduction of π-donor substituents increases luminescence quantum yield. • Dyes bio-imaging ability and cytotoxicity were investigated. Curcuminoids of boron difluoride, 1-aryl(hetaryl)-5-phenylpenta-2,4-dien-1-onates of boron difluoride, have been synthesized. A comparative study of the electronic structure, luminescent properties and their potential for applications in bio-imaging has been carried out. The influence of the electronic structure of α-substituents on the luminescence of compounds was studied by the methods of stationary and time-resolved luminescence spectroscopy and DFT modeling. The introduction of π-donor substituents leads to a noticeable bathochromic shift and an increase in the Stokes shift in the luminescence spectra. On going from σ-donor substituents in the phenyl ring to π-donor substituents, the luminescence quantum yield increases from 0.03 to 0.22. The maximum Stokes shift and high quantum yield of luminescence is exhibited by the complex with a stilbene substituent, which has the longest π-system and the maximum efficiency of charge transfer. Dyes are able to penetrate into the cells of the model cell line and accumulate, moreover, accumulation occurs mainly in the cytoplasm of cells. The compounds penetrate into the cells by 12 h of incubation without damaging it's structure and without causing rapid cell death. The submicromolar range of non-toxic concentrations during long-term incubation for a model cell line was determined, which is a characteristic of fluorescent imaging. Due to uniform distribution in the cytoplasm of cells dye with naphtyl substituent is promising for visualization of the cell cytoplasm. This leader compound has the lowest cytotoxicity for cells from the synthesized series of dyes, which makes it promising for further studies as a fluorescent imaging agent. The leader compound has the lowest cytotoxicity for cells from the synthesized series of dyes, which makes it promising for further studies as a fluorescent imaging agent. [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]