This study investigates lead-free organic-inorganic hybrids (CNH)[BiCl] () and (CNH)[BiBr] (), focusing on their structural, dielectric, ferroelectric, and optical properties. Both compounds exhibit paraelectric () to ferroelectric () phase transitions (PTs) at 230/233 K and 228/229 K, respectively, transitioning from orthorhombic () to monoclinic (2) phases, with distorted [BiX] octahedra forming 1D chains. Quasielastic neutron scattering and solid-state H NMR studies reveal the localized motion of azetidinium cations.
View Article and Find Full Text PDFWe have synthesized and characterized two novel lead-free organic-inorganic hybrid crystals: (S(CH))[BiI] (TBI) and (S(CH))[SbI] (TSI). Thermal DSC, TG, and DTA analyses indicate structural phase transitions (PTs) in both compounds; TBI undergoes two structural phase transitions at 314.2/314.
View Article and Find Full Text PDFHybrid organic-inorganic iodides based on Bi(III) and Sb(III) provide integrated functionalities through the combination of high dielectric constants, semiconducting properties and ferroic phases. Here, we report a pyrrolidinium-based bismuth () and antimony () iodides of (NCH)[MI] (M: Bi(III), Sb(III)) formula which are ferroelastic at room temperature. The narrow band gaps (~2.
View Article and Find Full Text PDFWe have synthesised and characterised novel organic-inorganic hybrid crystals: and ( and ). The thermal DSC and TG analyses indicate four structural phase transitions (PTs) at 366.2/366.
View Article and Find Full Text PDFWe report a metal-organic material of the following formula [DabcoH]·CrCl(HO)·2(Cl) (DabcoH = CHN, diprotonated 1,4-diazabicyclo[2.2.2]octanium).
View Article and Find Full Text PDFThe crystals of pure [(CH)NH][KFe(CN)] (TrMAFe) and [(CH)NH][KCo(CN)] (TrMACo) as well as their mixed crystals (TrMAFeCo), with different ratios of x = 0, 0.12, 0.18, 0.
View Article and Find Full Text PDFTwo organic-inorganic hybrid halobismuthates(iii), (NH2CHNH2)3[Bi2Cl9] (FBC) and (NH2CHNH2)3[Bi2Br9] (FBB), have been prepared with their structures revealed by single-crystal X-ray diffraction at various temperatures. FBC is characterized by one-dimensional (1D) [Bi2Cl9]3-∞ anionic chains built by edge-sharing BiCl6 octahedra, whereas FBB adopts a layer structure (2D) [Bi2Br9]3-∞. Both materials were found to exhibit a rich polymorphism in the solid state.
View Article and Find Full Text PDFWe have synthesised and characterised a novel organic-inorganic hybrid crystal, [(CH3)2NH2]2KCr(CN)6. The thermal DSC, TMA, DTG and DTA analyses indicate two solid-to-solid structural phase transitions (PTs). According to the X-ray diffraction experiments, the first PT at 220 K is isostructural, since it does not involve a change of the space group.
View Article and Find Full Text PDFHere we report the dynamics of organic cations as guest molecules in a perovskite host-framework. The molecular motion of CHNH (MAFe), (CH)NH (DMAFe) and (CH)NH (TrMAFe) in the cage formed by KFe(CN) units was studied using a combination of experimental methods: (i) thermal analysis, (ii) dielectric and electric studies, (iii) optical observations, (iv) EPR and H NMR spectroscopy and (v) quasielastic neutron scattering (QENS). In the case of MAFe and TrMAFe, the thermal analysis reveals one solid-to-solid phase transition (PT) and two PTs for the DMAFe crystal.
View Article and Find Full Text PDFA description of the thermal, structural, 1H NMR, electric and optical properties of four organic-inorganic hybrids, haloantimonates(iii) and halobismuthates(iii), based on homopiperidinium cation: (C6H14N)2SbCl5 (abbrev. HSC), (C6H14N)2SbBr5 (HSB), (C6H14N)2BiCl6[H3O] (HBC), (C6H14N)2BiBr5 (HBB), is presented. The common feature of the crystal structures of the studied compounds is the 1D (one-dimensional) chain for the anionic network in HSC, HSB and HBB, 1D hydrogen bond chain between 0D (zero-dimensional, isolated) BiCl6 octahedrons and hydronium moieties in HBC as well as a rich polymorphism in the solid state for all title compounds.
View Article and Find Full Text PDFThe simple organic crystal formamidinium iodide (FAI) appeared to be a novel semiconducting material in a wide temperature range. The electric properties of FAI and the role of formamidinium cation (FA) in the molecular mechanism of the solid-to-solid phase transitions (at 345 K (III → II) and 388 K (II → I)) were analysed. The creation of the ferroelastic domain structure in phases III and II was proved on the basis of observation under a polarizing microscope.
View Article and Find Full Text PDFThe content of glucose, fructose, sucrose, maltose and water were determined for multiflorous honey of Great Poland. The measurements were carried out for different fractions of honey and also for the liquefied honey at 40 °C. Water activity and pH were both determined for all samples.
View Article and Find Full Text PDF(C3N2H5)2[CoCl4] (ICC) was characterized in a wide temperature range by the single-crystal X-ray diffraction method. Differential scanning calorimetry revealed two structural phase transitions: continuous at 245.5 K (from phase I to II) and a discontinuous one at 234/237 K (cooling/heating) (II → III).
View Article and Find Full Text PDFDipyrazolium iodide triiodide, [C3N2H5(+)]2[I(-)·I3(-)], has been synthesized and studied by means of X-ray diffraction, differential scanning calorimetry, dielectric measurements, and UV-Vis spectroscopy. Two reversible, solid-solid phase transitions (Imma (I) ↔ (II) ↔Pbam (III)) at 254 K and 182/188 K respectively have been revealed. The anionic network experiences spectacular changes associated with a huge rebuilding of the inorganic network from [I(-)·I3(-)] to [I4(2-)].
View Article and Find Full Text PDFThe mechanism of molecular dynamics in the antibacterial/antifungal agent, triclosan (5-chloro-2-(2',4'-dichlorophenoxy)-phenol), in solid state was studied by (1)H NMR spectroscopy and periodic density functional theory (DFT) calculations. Temperature dependencies of the proton spin-lattice relaxation time (T1) in the ranges 86-293 and 90-250 K (at 15 and 24.667 MHz, respectively) and the second moment (M2) of the (1)H NMR resonant line in the range 103-300 K were measured.
View Article and Find Full Text PDFA (1)H and (19)F nuclear magnetic resonance study of [Mg(H2O)6](BF4)2 has confirmed the existence of two phase transitions at Tc1 ≈ 257 K and Tc2 ≈ 142 K, detected earlier by the DSC method. These transitions were reflected by changes in the temperature dependences of both proton and fluorine of second moments M2 (H) and M2 (F) and of spin-lattice relaxation times T1 (H) and T1 (F). The study revealed anisotropic reorientations of whole [Mg(H2O)6](2+) cations, reorientations by 180° jumps of H2O ligands, and aniso- and isotropic reorientations of BF4 (-) anions.
View Article and Find Full Text PDFThe crystal and molecular structure of the 2,3,5,6-tetramethylpyrazine (TMP) complex with 2,5-dibromo-3,6-dihydroxy-p-quinone (bromanilic acid, BRA) has been studied and the results are compared with TMP CLA (2,5-dichloro-3,6-dihydroxy-p-quinone (chloranilic acid, CLA) complex. The X-ray structure of TMP BRA complex indicates the formation of dimeric units, in which two BRA(-) anions are connected by two O-H···O (2.646(2) Å) hydrogen bonds, whereas the cations and anions are joined together by strong N(+)-H···O(-) (2.
View Article and Find Full Text PDFSome of haloantimonates(III) and halobismuthates(III) are ferroelectric. Bis(imidazolium) pentachloroantimonate(III), (C3N2H5)2SbCl5 (abbreviation: ICA) is the first example of such compounds with a one-dimensional anionic chain which exhibits ferroelectric properties. The relation between the ionic dynamics and network structure and the ferroelectric features is not clear.
View Article and Find Full Text PDFMolecular relaxation in antibacterial/antifungal agent: chloroxylenol (4-chloro-3,5-dimethylphenol, PCMX) in the solid state was studied by the (1)H NMR and quantum chemistry calculations. The temperature dependencies of the proton spin-lattice relaxation time (T1) in the ranges 15-273 K (at 24.667 MHz), 77-295 K (at 15 MHz), and 112-291 K at 90 MHz and the second moment (M2) of (1)H NMR resonant line in the range 106-380 K were measured.
View Article and Find Full Text PDFThree new organic-inorganic hybrids based on halogenoantimonates(III) and halogenobismuthates(III) with the morpholinium cation, [NH2(C2H4)2O]SbCl4, [NH2(C2H4)2O]SbBr4 and [NH2(C2H4)2O]BiBr4, have been prepared and characterized with DSC, TGA, DTA and single-crystal X-ray diffraction. The common feature of the crystal structures of the studied compounds is the presence of polyanionic ([MX4]∞(-)) and morpholinium (head-to-tail configuration) chains, which expand themselves parallel to each other. The antimonate derivatives are isomorphous, crystallizing in a centrosymmetric orthorhombic Pbca space group and show no phase transitions (PTs) between 110 and 370 K.
View Article and Find Full Text PDFProton spin-lattice relaxation times T1 at 24.7 MHz and 15 MHz and second moment of NMR line have been applied to study molecular dynamics of a novel ferroelectric (NH4)2H2P2O6 (T(c)=178 K) in the temperature range 10-290 K. Low-temperature T1 behaviour below Tc is interpreted in terms of Haupt's theory and Schrödinger correlation time of tunnelling jumps.
View Article and Find Full Text PDF(1)H spin-lattice relaxation rates in glycerol solutions of selected nitroxide radicals at temperatures between 200 K and 400 K were measured at 15 MHz and 25 MHz. The frequency and temperature conditions were chosen in such a way that the relaxation rates go through their maximum values and are affected by neither the electron spin relaxation nor the electron-nitrogen nucleus hyperfine coupling, so that the focus could be put on the mechanisms of motion. By comparison with (1)H spin-lattice relaxation results for pure glycerol, it has been demonstrated that the inter-molecular electron spin-proton spin dipole-dipole interactions are affected not only by relative translational motion of the solvent and solute molecules, but also by their rotational dynamics as the interacting spins are displaced from the molecular centers; the eccentricity effects are usually not taken into account.
View Article and Find Full Text PDFSolid State Nucl Magn Reson
October 2011
A general theory of field dependent spin-lattice relaxation for nuclei of the spin quantum number 1/2 (1H, 19F, 13C) caused by dipole-dipole interactions with neighboring quadrupolar nuclei (nuclei possessing a quadrupolar moment) is presented. The theory is valid for arbitrary motional conditions and should be treated as a quadrupolar counterpart of the paramagnetic relaxation enhancement theory. When the energy level splitting of the dipolar spin (I=1/2) matches one of the transition frequencies of the quadrupolar nuclei one can observe a local enhancement of the dipolar spin relaxation (referred to as "quadrupolar peaks").
View Article and Find Full Text PDFMolecular dynamics of a polycrystalline sample of (CH(3)NH(3))(5)Bi(2)Br(11) (MAPBB) is studied on the basis of the proton T(1) (55.2 MHz) relaxation time and the proton second moment of NMR line. The T(1) (55.
View Article and Find Full Text PDFMolecular dynamics of a polycrystalline sample of [(CH(3))(4)P](3)Sb(2)Br(9) (PBA) has been studied on the basis of the T(1) (24.7 MHz) relaxation time measurement, the proton second moment of NMR and the earlier published T(1) (90 MHz) relaxation times. The study was performed in a wide range of temperatures (30-337 K).
View Article and Find Full Text PDF