Highly luminescent crystals of a novel linear π-conjugated thiophene–phenylene co-oligomer with a benzothiadiazole fragment

2019 ◽  
Vol 75 (6) ◽  
pp. 1076-1085 ◽  
Author(s):  
Valery A. Postnikov ◽  
Nataliya I. Sorokina ◽  
Artem A. Kulishov ◽  
Maria S. Lyasnikova ◽  
Vadim V. Grebenev ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Liquid Crystalline ◽  
Photoluminescence Spectra ◽  
X Ray Diffraction ◽  
Growth From Solutions ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Kinetics Of ◽  
Thermal Stability Of

The synthesis, growth from solutions and structure of crystals of a new linear thiophene–phenylene co-oligomer with a central benzothiadiazole fragment with a conjugated core, (TMS-2T-Ph)2-BTD, are presented. Single-crystal samples in the form of needles with a length of up to 7 mm were grown and their crystal structure was determined at 85 K and 293 K using single-crystal X-ray diffraction. The conformational differences between the crystal structures are insignificant. The parameters of melting and liquid crystalline phase transitions of (TMS-2T-Ph)2-BTD were established using differential scanning calorimetry and the thermal stability of the crystals was investigated using thermogravimetric analysis. The optical absorption and photoluminescence spectra of the solutions and crystals of (TMS-2T-Ph)2-BTD were obtained, and the kinetics of their photodegradation under the action of UV radiation were studied.

Growth and luminescence properties of Pr3+-doped LaCl3 single crystal

2016 ◽  
Vol 09 (02) ◽  
pp. 1650022
Author(s):  
Zihan Liu ◽  
Qinhua Wei ◽  
Laishun Qin ◽  
Hongsheng Shi ◽  
Kangying Shu
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Ultra Violet ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Xrd Pattern ◽  
X Ray ◽  
Decay Times ◽  
Vertical Bridgman ◽  
Dominant Peak

A transparent LaCl3:Pr[Formula: see text] single crystal with a dimension of [Formula: see text] [Formula: see text][Formula: see text]mm was grown by vertical Bridgman method. The differential scanning calorimetry (DSC) shows that the melting point of LaCl3:Pr[Formula: see text] crystal is about 841.5[Formula: see text]C. The powder X-ray diffraction (XRD) pattern proves the crystal structure of LaCl3:Pr[Formula: see text] is hexagonal with space group P63/m. There is a dominant peak centered at 335[Formula: see text]nm and a weaker peak located at 400[Formula: see text]nm under X-ray excitation, while three peaks located at 335[Formula: see text]nm, 356[Formula: see text]nm and 400[Formula: see text]nm under ultra-violet. The peaks of 335[Formula: see text]nm and 356[Formula: see text]nm can be ascribed to the transition of 5d–4f of Pr[Formula: see text], while the 400[Formula: see text]nm maybe related to LaCl3 host. Decay times were fitted to be about 14.5[Formula: see text]ns for 335[Formula: see text]nm, 14.6[Formula: see text]ns for 356[Formula: see text]nm and 1.3[Formula: see text]ns for 400[Formula: see text]nm. The experimental results show that the LaCl3:Pr[Formula: see text] crystal will be a promising scintillator.

Synthetic norsethite, BaMg(CO3)2: revised crystal structure, thermal behaviour and displacive phase transition

2014 ◽  
Vol 78 (7) ◽  
pp. 1589-1611 ◽  
Author(s):  
H. Effenberger ◽  
T. Pippinger ◽  
E. Libowitzky ◽  
C. L. Lengauer ◽  
R. Miletich
Keyword(s):  
Crystal Structure ◽  
Oxygen Atom ◽  
Single Crystal ◽  
Thermal Analyses ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Displacive Phase Transition ◽  
Changing Trend

AbstractThe crystal structure of synthetic BaMg(CO3)2 whose mineral name is norsethite was re-investigated by single-crystal X-ray diffraction. Complementary in situ high- and low-temperature studies by means of vibrational spectroscopy (Raman, IR), powder X-ray diffraction techniques and thermal analyses were performed. Diffraction images (298 K) revealed weak superstructure reflections caused by the displacement of the O atoms in the earlier considered Rm structure model (a = 5.0212(9), cnew = 2 cold = 33.581(6) Å , Rc, Z = 6, R1 = 0.011, sinθ/λ < 0.99 Å –1). Thermal analyses reveal decarbonatization in two decomposition steps above 750 K, and the heat-flow curves (difference scanning calorimetry) give clear evidence of a weak and reversible endothermal change at 343±1 K. This agrees with a discontinuity in the IR and single-crystal Raman spectra. The changing trend of the c/a ratio supports this discontinuity indicating a temperature-induced structural transition in the range between 343 and 373 K. As the change of the unit-cell volume is almost linear, the character of the transition is apparently second order and matches the mechanism of a subtle displacement of the oxygen atom position. The apparent instability of the Rc structure is also evidenced by the remarkably larger anisotropic displacement of the oxygen atom.

A Long-Chain Phosphine Designed as a Metallomesogen Generator—Synthesis and Coordination Properties

2004 ◽  
Vol 57 (2) ◽  
pp. 157 ◽  
Author(s):  
Daravong Soulivong ◽  
Dominique Matt ◽  
Jack Harrowfield ◽  
Loïc Toupet
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Liquid Crystalline ◽  
X Ray Diffraction ◽  
Subsequent Reaction ◽  
X Ray ◽  
Coordination Properties ◽  
Long Chain

The long-chain phosphine Me2PC≡C(p-C6H4CHNR C8) [L; RC8 = p-C6H4OC(O)(p-C6H4OC8H17)] has been prepared in two steps starting from 4-ethynylbenzaldehyde (1): (a) condensation of 1 with H2NRC8 (2) afforded the corresponding imine 3 (yield 86%) which displays liquid-crystalline behaviour; (b) deprotonation of 3 with LiNPri2 and subsequent reaction with Me2PCl gave a mixture of the phosphine–alkyne L and the precursor 3 (L : 3 = 60 : 40). Reaction of this mixture with [PtCl2(PhCN)2] produced cis-[PtCl2L2] (4) and provided an efficient means of separating the phosphine from 3. The crystal structure of imine 3 has been determined by single-crystal X-ray diffraction and analysis of this structure provides a basis for understanding both the mesogenic character of 3 and its absence in the complex 4.

scholarly journals Crystal chemistry of fluorcarletonite, a new mineral from the Murun alkaline complex (Russia)

2020 ◽  
Vol 32 (1) ◽  
pp. 137-146 ◽  
Author(s):  
Ekaterina Kaneva ◽  
Tatiana Radomskaya ◽  
Ludmila Suvorova ◽  
Irina Sterkhova ◽  
Mikhail Mitichkin
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Structure Refinement ◽  
New Mineral ◽  
X Ray Diffraction ◽  
Alkaline Complex ◽  
Scanning Calorimetry ◽  
Oh Groups ◽  
X Ray ◽  
Weight Losses

Abstract. This paper reports the first description of the crystal structure and crystal chemical features of fluorcarletonite, a new mineral from the Murun potassium alkaline complex (Russia), obtained by means of single-crystal and powder X-ray diffraction (XRD), electron microprobe analysis (EMPA), thermogravimetry (TG), differential scanning calorimetry (DSC), and Fourier transform infrared (FTIR) spectroscopy. The crystal structure of fluorcarletonite, KNa4Ca4Si8O18(CO3)4(F,OH)⚫ H2O, a rare phyllosilicate mineral, contains infinite double-silicate layers composed of interconnected four- and eight-membered rings of SiO4 tetrahedra and connected through the interlayer K-, Na- and Ca-centered polyhedra and CO3 triangles. The X-ray diffraction analysis confirms the mineral to be tetragonal, P4∕mbm, a=13.219(1) Å, c=16.707(2) Å, V=2919.4(6) Å3 (powder XRD data), a=13.1808(5) Å, c=16.6980(8) Å, V=2901.0(3) Å3 (single-crystal XRD data, 100 K). The EMPA (average from 10 analyses) gave the following composition (wt %): SiO2 44.1(6), CaO 20.0(3), Na2O 11.1(3), K2O 4.5(2), F 1.3(5), TiO2 0.1(1) and Al2O3 0.03(3). The TG–DSC analysis confirmed the presence of H2O and CO2 (weight losses of 1.17 % and 14.9 %, respectively). The FTIR spectrum acquired in the range from 4000 to 400 cm−1 reveals the presence of H2O, CO3 and OH groups. The average formula of fluorcarletonite calculated from the results of EMPA and crystal structure refinement is K1.04Na3.89Ca3.87Ti0.01Si7.99Al0.01O18(CO3)3.86(F0.72OH0.28)⚫1.11H2O.

Dimeric Liquid Crystalline Epoxy Resins Containing Azo Group: Mesogenic Behavior and Curing with Anhydride

2010 ◽  
Vol 123-125 ◽  
pp. 955-958
Author(s):  
De Wen Zhou ◽  
Li Yan Liang ◽  
Man Geng Lu
Keyword(s):  
Epoxy Resins ◽  
Liquid Crystalline ◽  
Cure Kinetics ◽  
X Ray Diffraction ◽  
Melting Points ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Azo Group ◽  
Kinetics Of

A series of dimeric liquid crystalline (LC) epoxy monomers containing azo groups with different length of central spacers were synthesized. The mesogenic behavior of these monomers was characterized by differential scanning calorimetry(DSC), polarized optical microscopy (POM) and wide-angle X-Ray diffraction(WAXS). Like other dimeric LC epoxy monomers, the melting points, clear points and mesophase of these compounds were influenced by the carbon numbers of the central spacers. Cure kinetics of these monomers with anhydride was studied by non-isothermal DSC at different heating rates. With the increasing of conversion, the values of activation energy show a tendency to decrease. The formation and development of LC phase during curing were also studied by POM. Finally LC thermosets with nematic phase were obtained.

Crystal structure of an inclusion complex between chiral monoaza-15-crown-5 and S(–)-1-phenyl-ethyl ammonium percholorate

2003 ◽  
Vol 218 (5) ◽  
Author(s):  
Süheyla Özbey ◽  
F. B. Kaynak ◽  
M. Toğrul ◽  
N. Demirel ◽  
H. Hoşgören
Keyword(s):  
Crystal Structure ◽  
Inclusion Complex ◽  
Single Crystal ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
New Type

AbstractA new type of inclusion complex, S(–)-1 phenyl ethyl ammonium percholorate complex of R-(–)-2-ethyl - N - benzyl - 4, 7, 10, 13 - tetraoxa -1- azacyclopentadecane, has been prepared and studied by NMR, IR and single crystal X-ray diffraction techniques. The compound crystallizes in space group

scholarly journals An investigation of polyhedral deformation in two mixed-metal diarsenates: SrZnAs2O7and BaCuAs2O7

2015 ◽  
Vol 71 (4) ◽  
pp. 330-337 ◽  
Author(s):  
Sabina Kovač ◽  
Ljiljana Karanović ◽  
Tamara Đorđević
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
General Formula ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
Hydrothermal Conditions ◽  
X Ray ◽  
Open Framework ◽  
Geometrical Characteristics ◽  
Barium Copper

Two isostructural diarsenates, SrZnAs2O7(strontium zinc diarsenate), (I), and BaCuAs2O7[barium copper(II) diarsenate], (II), have been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction. The three-dimensional open-framework crystal structure consists of corner-sharingM2O5(M2 = Zn or Cu) square pyramids and diarsenate (As2O7) groups. Each As2O7group shares its five corners with five differentM2O5square pyramids. The resulting framework delimits two types of tunnels aligned parallel to the [010] and [100] directions where the large divalent nine-coordinatedM1 (M1 = Sr or Ba) cations are located. The geometrical characteristics of theM1O9,M2O5and As2O7groups of known isostructural diarsenates, adopting the general formulaM1IIM2IIAs2O7(M1II= Sr, Ba, Pb;M2II= Mg, Co, Cu, Zn) and crystallizing in the space groupP21/n, are presented and discussed.

scholarly journals Crystal Structure of Moganite and Its Anisotropic Atomic Displacement Parameters Determined by Synchrotron X-ray Diffraction and X-ray/Neutron Pair Distribution Function Analyses

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 272
Author(s):  
Seungyeol Lee ◽  
Huifang Xu ◽  
Hongwu Xu ◽  
Joerg Neuefeind
Keyword(s):  
Crystal Structure ◽  
Distribution Function ◽  
Single Crystal ◽  
Pair Distribution Function ◽  
Atomic Displacement ◽  
Single Crystal Xrd ◽  
X Ray Diffraction ◽  
X Ray ◽  
Neutron Pair ◽  
Atomic Displacement Parameters

The crystal structure of moganite from the Mogán formation on Gran Canaria has been re-investigated using high-resolution synchrotron X-ray diffraction (XRD) and X-ray/neutron pair distribution function (PDF) analyses. Our study for the first time reports the anisotropic atomic displacement parameters (ADPs) of a natural moganite. Rietveld analysis of synchrotron XRD data determined the crystal structure of moganite with the space group I2/a. The refined unit-cell parameters are a = 8.7363(8), b = 4.8688(5), c = 10.7203(9) Å, and β = 90.212(4)°. The ADPs of Si and O in moganite were obtained from X-ray and neutron PDF analyses. The shapes and orientations of the anisotropic ellipsoids determined from X-ray and neutron measurements are similar. The anisotropic ellipsoids for O extend along planes perpendicular to the Si-Si axis of corner-sharing SiO4 tetrahedra, suggesting precession-like movement. Neutron PDF result confirms the occurrence of OH over some of the tetrahedral sites. We postulate that moganite nanomineral is stable with respect to quartz in hypersaline water. The ADPs of moganite show a similar trend as those of quartz determined by single-crystal XRD. In short, the combined methods can provide high-quality structural parameters of moganite nanomineral, including its ADPs and extra OH position at the surface. This approach can be used as an alternative means for solving the structures of crystals that are not large enough for single-crystal XRD measurements, such as fine-grained and nanocrystalline minerals formed in various geological environments.

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