Crystal structure of boron difluoride 3-phenylthiopentane-2,4-dionate. π stacking interactions and luminescence of boron difluoride acetyl acetonates

The crystal structure of boron difluoride 3-phenylthiopentane-2,4-dionate was determined. The relationship between the structure and luminescent properties is traced in the series of boron difluoride acetyl acetonates (acetyl acetonate, phenylacetyl acetonate, and phenylthioacetyl acetonate). The presence of the π stacking interactions in boron difluoride phenylthioacetyl acetonate crystals leads to increased intensity and bathochromic shift of the fluorescence band.     

Reversible luminescence thermochromism of dibenzoyl(methanato)boron difluoride

Reversible luminescence thermochromism of dibenzoyl(methanato)boron difluoride was found. A substantial hypsochromic shift of the luminescence band maximum (60 nm) with a temperature decrease from 300 to 77 K was observed, and the luminescence color changed from green to blue. A considerable decrease (by 0.386 Å) in the unit cell parameters along the c axis was detected by X-ray diffractometry when the temperature of the crystal decreased from 293 to 123 K. Shortening of the distances between the planes of adjacent molecules (stacking factor) weakens the interaction between the dimers and enhances the monomeric and excimeric luminescence. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 1032–1034, April, 2005.     

Size-dependent luminescence of boron difluoride β-diketonates

Size-dependent luminescence properties of boron difluoride β-diketonates were detected. Most compounds investigated are characterized by noticeable hypsochromic shifts of luminescence band maxima on going from bulk crystals to microcrystals. However, a decrease in the crystal size of (dibenzoylmethanato)boron difluoride with unique supramolecular structure was accompanied by a bathochromic shift of the luminescence band maximum. Size-dependent luminescence properties of complexes examined were analyzed in the framework of excitonic mechanism. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1168–1170, June, 2008.     

Fluorescence and photochemical properties of crystalline boron difluorides β-diketonato

The fluorescence and photochemical properties of crystalline β-diketonatoboron difluorides (DBD) RCOCHCOR¹BF₂ were studied. These compounds are characterized by relatively high photochemical stability. The introduction of electron-donating groups into the aromatic α-substituent of the chelate ring increases and the introduction of electron-withdrawing groups decreases the fluorescence intensity of DBD. Anisoylbenzoylmethanotoboron difluoride was found to exhibit the highest fluorescence intensity. The substituents were shown to influence the relative arrangement of singlet and triplet ηπ^* and ππ^* levels and luminescence properties of compounds. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1030–1033, June, 2000.     

Crystal structure and excimer fluorescence of dibenzoylmethanatoboron difluoride

Fluorescence properties of dilute and concentrated solutions of dibenzoylmethanatoboron difluoride and its crystals were studied. Excimers are formed in concentrated solutions and crystals of dibenzoylmethanatoboron difluoride. The crystal structure of dibenzoylmethanatoboron difluoride was determined by X-ray diffraction analysis. It was found that the molecules of dibenzoylmethanatoboron difluoride are coplanar with an interplanar distance of 3.6 .     

The structure and luminescence of isomeric boron difluoride acetylnaphtholates

A comparative study of the fluorescence of solutions and crystals of isomeric boron difluoride acetylnaphtholates, 2-acetyl-1-naphtholate (1) and 1-acetyl-2-naphtholate (2), was performed. The compounds only differ in the position of the naphthyl group with respect to the chelate ring. An important role played by the stacking factor in the formation of the fluorescent properties of the complexes was revealed. The planar structure of the molecule and effective overlapping of the π systems of neighboring molecules of 1 cause a substantial bathochromic shift of its spectrum and a sharp increase in the intensity of excimeric fluorescence.     

Crystal and molecular structure of <Emphasis Type="Italic">tris</Emphasis>-(1,1,1-trifluoro-5,5-dimethylhexan-2,4-dionato)iron(III)

Synthesis and results of the single crystal X-ray diffraction study of iron(III) pivaloyltrifluoroacetonate are reported. Crystal data for C₂₄H₃₀FeF₉O₆: a = 9.2205(6) Å, b = 9.6584(10) Å, c = 17.3799(17) Å, α = 75.902(2)°, β = 80.517(3)°, γ = 82.746(3)°, space group P-1, V = 1474.6(2) ų, Z = 2. The structure is molecular with the octahedral environment of Fe atom, Fe-O_av 1.991 Å, ∠O-Fe-O_av 86.48°. The van der Waals energy of intermolecular interactions is calculated and compared to thermodynamic data.     

Crystal and molecular structure of (hexafluoroacetylacetonato) (pivaloylacetonato)copper(II)

The crystal structure of (hexafluoroacetylacetonato)(pivaloylacetonato)copper(II) has been determined. Crystal data for CuO₄C₁₃H₁₄F₆: a = 8.288(2) Å, b = 8.682(2) Å, c = 12.307(2) Å; α = 90.75(3)°, β = 94.29(3)°, γ = 106.60(3)°; V = 845.7(3) ų, space group \(P\overline 1 \), Z = 2, d_calc = 1.617 g/cm³. The coordination polyhedron of the copper atom is formed by four oxygen atoms of two different β-diketonate ligands with Cu-O distances within 1.874–1.946 Å; the O-Cu-O bond angles are 94.8° and 90.6°. The complexes are united into centrosymmetrical “dimers” with Cu...Cu distances of 4.365 Å.     

Crystal structure of oxotitanium(IV) 2,2,6,6-tetramethyl-3,5-heptanedionate

The structure of titanyl dipivalylmethanate TiO(dpm)₂ has been studied by X-ray diffraction analysis. The compound has a molecular structure formed by isolated centrosymmetrical dimers [TiO(dpm)₂]₂; the unit cell contains two structurally related, crystallographically unique binuclear molecules. The Ti...Ti distance in the dimer is 2.73 Å. Crystal data for Ti₂C₃₆H₇₆O₁₀: a = 32.477(6) Å, b = 14.409(3) Å, c = 25.630(5) Å; β = 107.82(3)°, space group C2/c, Z = 8, d _calc = 1.002 g/cm³.     

Crystal structure of <Emphasis Type="Italic">trans</Emphasis>-bis(trifluoro-acetylacetonato)copper(II)

Triclinic modification of trans-bis(trifluoroacetylacetonato)copper(II) is studied by single crystal X-ray diffraction (diffractometer X8 APEX BRUKER, MoK _α radiation, T = 173(2) K). The structure is molecular. Square environment of the Cu atom (Cu-O_av 1.916 Å, ∠O-Cu-O_av 93.4°) is completed to a bipyramid by two atoms of neighboring molecules, Cu...C_γ 3.18 Å and 3.23 Å.     

Crystal structure of lithium(i) 1,1,1,-trifluoro-5,5-dimethyl-2,4-hexanedionate

Lithium pivalyltrifluoroacetonate has been studied by X-ray crystallography. The compound has a structure of a coordination polymer [Li(pta)]_∞ with Li…Li distances of 2.74 Å. Crystal data for C₁₆H₂₀F₆Li₂O₄: a = 19.151(4) Å, b = 10.723(2) Å, c = 19.801(4) Å, space group Pbca, Z = 8, d _calc = 1.321 g/cm³.     

Crystal structure and thermal investigation of bis-(1-thenoyl-4,4,4-trifluorobutan-1,3-dionato) lead(II)

Lead(II) complex with thenoyltrifluoroacetone has been prepared and characterized by IR spectroscopy, powder and single crystal X-ray diffraction. Crystal data for PbO₄S₂F₆C₁₆H₈: a = 20.457(4) Å, b = 11.292(2) Å, c = 8.409(2) Å; β = 91.37(3)°, space group C2/c, Z = 4, d _calc = 2.222 g/cm³. The molecule of the complex is non-planar, average distances Pb-O are 2.384 Å, chelate angle O-Pb-O is 75.0°. The structure is of polymeric chain nature, Pb...Pb separation in the chains being 4.311 Å. The complex Pb(ttf)₂ is stable under heating up to 250°C. The compound is less volatile than Cu(ttf)₂ or Fe(ttf)₃.     

Crystal structure and fluorescence properties of p-nitrobenzoylanisoylmethane and its complex with boron difluoride

The crystal and molecular structures of p- and m-nitrobenzoylanisoylmethanatoboron difluoride were determined. The spectral luminescence properties of these compounds were studied and compared.     

Crystal structure and vapor pressure of a copper(II) complex with 2,2,6,6-tetramethyl-4-fluoroheptane-3,5-dione

Synthesis and single crystal X-ray diffraction study were carried out for copper(II) 2,2,6,6-tetramethyl-4-fluoroheptane-3,5-dionate (Bruker AXS P4 automated diffractometer, MoK _α radiation). Crystal data for C₂₂H₃₆CuF₂O₄: a = 5.9165(4) Å, b = 10.2787(7) Å, c = 10.5223(8) Å, α = 81.383(3)°, β = 76.106(3)°, γ = 83.778(3)°, space group P $\bar 1$ , V = 612.42(7) ų, Z = 1, d _x = 1.264 g/cm³. The structure is molecular; the copper atom has a square plane coordination formed by the oxygen atoms of two β-diketonate ligands; the average Cu-O distance is 1.895 Å, ∠O-Cu-O 92.5°. Only van der Waals interactions are realized between the molecules in the structure. The temperature dependences of the saturated vapor pressure were studied by the mass transfer technique, and the standard thermodynamic parameters of sublimation were derived for the complex, ΔH _subl ⁰ = 115.6 ± 1.1 kJ/mol, ΔS _subl ⁰ = 204.9 ± 2.5 J/mol·K.     

Crystal structure and thermodynamic stability of an acetone solvate of bis(trifluoroacetylacetonato)copper(II)

A solvate [Cu(CF₃COCHCOCH₃)₂(CH₃COCH₃)] has been synthesized and characterized for the first time. According to X-ray structural data (diffractometer X8 APEX BRUKER, radiation MoK _α, T = 150 K), it crystallizes in the monoclinic crystal system, space group P2₁/c, a = 8.9940(4) Å, b = 22.3966(11) Å, c = 8.1884(3) Å, β = 92.705(2)°, V = 1647.59(12) ų, Z = 4, d _calc = 1.725 g/cm³, final R = 0.0272. The structure is molecular. In the equatorial plane the atom Cu(II) is surrounded with four oxygen atoms of two chelating ligands (CF₃COCHCOCH₃)^?; Cu-O distances 1.927–1.937 Å, O-Cu-O angles 86.18–93.30° and 170.18–175.67°. Square coordination of Cu is complemented to the square-pyramidal one by the oxygen atom of an acetone molecule behaving as an axial ligand; Cu-O_acetone 2.342 Å, O-Cu-O_acetone 89.66–100.11°. In the studied compound disorder of one of the chelate ligands implies the co-existance of the molecules in the cis- and trans-configuration in the crystal under ratio 54.6:45.4. In air the solvate rapidly degrades losing acetone, while in a sealed vessel melts around 313 K. Temperature dependence of equilibrium vapor pressure of acetone over the complex was measured with the static spoon gauge technique, thermodynamic characteristics of its dissociation process being derived: [Cu(CF₃COCHCOCH₃)₂(CH₃COCH₃)]_s = [Cu(CF₃COCHCOCH₃)₂]_s + CH₃COCH_3g, ΔH _av ⁰ = 49.6(3) kJ/mol, ΔS _av ⁰ = 152(1) J/(mol K), ΔG _av ⁰ = 4.30(2) kJ/mol.     

Crystal structure of lithium β-diketonate containing perfluorobutyl and pyridyl substituents

The crystal structure of lithium 4,4,5,5,6,6,7,7,7-nonafluoro-1-(3-pyridyl)heptane-1,3-dionate hydrate was established by X-ray diffraction. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 561–571, March, 2008.     

Synthesis and structural investigation of hafnium(IV) complexes with acetylacetone and trifluoroacetylacetone

Two volatile hafnium(IV) complexes with acetylacetone and trifluoroacetylacetone (HL) have been prepared and their structures have been studied at ?30°C. Crystal data for C₂₀H₂₈HfO₈: a = 21.5493(4) Å, b = 8.36720(10) Å, c = 13.9905(3) Å; β = 116.5550(10)°, space group C2/c, Z = 4, d _calc = 1.692 g/cm³, R = 0.015. Crystal data for C₂₀H₁₆F₁₂HfO₈: a = 8.1039(12) Å, b = 11.4499(14) Å, c = 15.790(2) Å; α = 99.341(4)°, β = 103.175(4)°, γ = 108.185(4)°, space group P?1, Z = 2, d _calc = 2.003 g/cm³, R = 0.074. Both structures are molecular and comprise isolated complex molecules HfL₄. The hafnium atom is coordinated with eight oxygen atoms of four β-diketonate ligands, Hf-O distances varying from 2.153 Å to 2.191 Å. The molecules make van der Waals contacts in the structures.     

Synthesis and condensation reactions of the boron difluoride complex with 3-acetyl-4-hydroxy-1-methyl-2-quinolone

A reaction of 3-acetyl-4-hydroxy-1-methyl-2-quinolone with boron trifluoride etherate gave its boron difluoride complex. Condensation of this complex with various carbonyl compounds afforded new 2-quinolone derivatives (polymethine and styryl dyes) that intensely absorb in the visible region of the spectrum and show effective fluorescence. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1701–1706, August, 2008.     

Structure of the hexanuclear Cu(II) β-diketonate complex

The structure of the hexanuclear copper(II) β-diketonate complex with gfa (hexafluoroacetylacetone) and dpm (dipivalylmethanate) ligands was studied by low-temperature (T = 100 K) X-ray diffraction. Crystal data for Cu₆(gfa)₄(dpm)₄(OH)₄ [C₆₄H₈₄Cu₆F₂₄O₂₀]: a = 28.2364(7) Å, b = 12.8072(3) Å, c = 24.7199(7) Å, β= 115.900(1)°, V = 8041.5(4) ų, space group C2/m, Z = 4, d _calc 1.661 g/cm³. The coordination polyhedra of the copper atoms — squares and octahedra — are formed by the oxygen atoms of the gfa and dpm ligands and groups. In all cases, the Cu-O distances vary from 1.89 Å to 2.13 Å. The complexes follow the sites of the rhombohedral sublattice with the parameters a _c ≈ 14.4 Å and a _c ≈ 61.5°.