Aromatic C–H⋯π, C–H⋯O and parallel aromatic–aromatic interactions in the crystal structure of meso-tetrakis[4-(benzyloxy)phenyl] porphyrin

Analysis of the crystal packing of the title porphyrin derivative ( C72H54N4O4) suggests no classical hydrogen bonds between neighbor molecules. X-ray crystal structure shows that all benzyl units of this porphyrin have close C–H⋯π weak contacts with phenyl or porphyrinyl units forming a network of porphyrin rings. Also C–H⋯O and parallel aromatic–aromatic weak interactions play an important role in structure extension. All of these interactions control the crystal packing of molecules. X-ray diffraction was used to perform single crystal analysis. The structure was solved in the triclinic space group P-1, with unit cell parameters: a = 8.0597(3) Å, b = 11.6862(4) Å, c = 14.2572(5) Å, α = 96.173(3)°, β = 93.150(4)°, and γ = 93.679(3)°, V = 1329.72(8) Å3, Z = 1

Fidelity susceptibility in Gaussian Random Ensembles

The fidelity susceptibility measures sensitivity of eigenstates to a change of an external parameter. It has been fruitfully used to pin down quantum phase transitions when applied to ground states (with extensions to thermal states). Here we propose to use the fidelity susceptibility as a useful dimensionless measure for complex quantum systems. We find analytically the fidelity susceptibility distributions for Gaussian orthogonal and unitary universality classes for arbitrary system size. The results are verified by a comparison with numerical data.Comment: 2nd version, 5+5pp, comments welcom

2,3-O-Isopropylidene-1-O-p-tolylsulfonylglycerol

In the title compound, C13H18O5S, the five-membered ring has an envelope conformation. The packing involves four C— H O interactions, three of which combine to form layers of molecules parallel to the bc plane

Spectroscopic and crystallographic characterization of two cathinone derivatives : 1-(4-fluorophenyl)-2-(methylamino)pentan-1-one (4-FPD) hydrochloride and 1-(4-methylphenyl)-2-(ethylamino)pentan-1-one (4-MEAP) hydrochloride

Purpose In this study, we performed identification and physicochemical characterization of two cathinone derivatives, 4-FPD and 4-MEAP, found in market-available materials. Methods The compounds were characterized by electrospray ionization ion trap mass spectrometry (MS) in MS2 and MS3 modes, gas chromatography–MS, infrared, Raman and ultraviolet-visible spectroscopies, X-ray crystallography, differential scanning calorimetry and nuclear magnetic resonance spectroscopy. Results We could obtain detailed and comprehensive physicochemical characterization of 4-FPD and 4-MEAP—new cathinone derivatives available on the designer drugs market. Conclusions Dynamic growth in the number of psychoactive substances available on the designer drug markets makes it compulsory to obtain analytical data allowing unequivocal identification of these drugs in the fastest possible way. In this study we presented analytical data useful in quick identification of the investigated compounds

On determination of statistical properties of spectra from parametric level dynamics

We analyze an approach aiming at determining statistical properties of spectra of time-periodic quantum chaotic system based on the parameter dynamics of their quasienergies. In particular we show that application of the methods of statistical physics, proposed previously in the literature, taking into account appropriate integrals of motion of the parametric dynamics is fully justified, even if the used integrals of motion do not determine the invariant manifold in a unique way. The indetermination of the manifold is removed by applying Dirac's theory of constrained Hamiltonian systems and imposing appropriate primary, first-class constraints and a gauge transformation generated by them in the standard way. The obtained results close the gap in the whole reasoning aiming at understanding statistical properties of spectra in terms of parametric dynamics.Comment: 9 pages without figure

(2,2-Dimethyl-1,3-dioxolan-4-yl)methyl 3-carboxy­propanoate

In the title compound, C10H16O6, the five-membered ring has an envelope conformation. The packing involves hydrogen-bonded carboxylic acid inversion dimers and three C—H⋯O inter­actions

Dimorphism of 1,4-dibromo-2,5-bis(bromomethyl)benzene: crystallographic and physico-chemical investigations

Two polymorphic modifications of 1,4-dibromo-2,5-bisIJbromomethyl)benzene have been discovered and structurally characterized; their thermodynamic relationships and transformation behaviour have been investigated. Form I crystallizes in the triclinic space group P1¯, whereas form II crystallizes monoclinic in space group P21/c, both with imposed inversion symmetry of the molecule. Their crystal structures involve layers, in which the molecules are linked by intermolecular Br⋯Br interactions to form similar systems of linked rings. Initial studies involved batches consisting of pure form I or a mixture of I with traces of II (as obtained by chance from the synthesis), but solvent-mediated conversion experiments in various solvents clearly prove that form II is the thermodynamically stable form at room temperature. Thermomicroscopic and heating-rate-dependent DSC measurements show that the melting point of form I is slightly higher than that of form II and that the higher melting polymorph exhibits the lower heat of fusion. Therefore, form I becomes thermodynamically stable at higher temperatures and both forms are related by enantiotropism. This is also in agreement with the density rule, because the low-temperature form II exhibits the higher density. Isothermal annealing of both modifications at different temperatures reveals a thermodynamic transition temperature of about 135 °C, which is in excellent agreement with that of 137.5 °C calculated from the melting temperatures and the heat of fusion of both forms. The high-temperature form can easily be prepared pure by solidification of the melt, which is in agreement with Ostwald's step rule, because form I crystallizes at a temperature where it is thermodynamically metastable. A qualitative energy/ temperature diagram is presented

Identification and characterization of new designer drug 4-fluoro-PV9 and [alfa]-PHP in the seized materials

In this study, we present identification and physicochemical characterization of new cathinone derivatives, 4-fluoro-PV9 and already known a-PHP in seized materials. Although the disclosure of a-PHP from an illegal product had been reported and characterized to some extent, the data on a-PHP are also presented together with those of 4-fluoro-PV9. The data of characterization for the two compounds were obtained by high-performance liquid chromatography (HPLC)–mass spectrometry and HPLC– diode array detection, electrospray ionization/ion trap mass spectrometry in MS2 and MS3 modes, gas chromatography– mass spectrometry, thermogravimetric analysis, differential scanning calorimetry, Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, and nuclear magnetic resonance spectroscopy. To our knowledge, this is the first report for identification and detailed characterization of 4-fluoro-PV9 circulated on the illegal drug market

Crystal structure of sparteinium tetrachlorocuprate monohydrate‑packing polymorph

A new polymorph of sparteinium tetrachlorocuprate monohydrate [(C15H28N2)CuCl4·H2O] is reported. The structure of the analyzed crystal was solved in the orthorhombic P212121 space group with the following unit cell parameters at 295 K: a = 9.7722(2) Å; b = 13.4582(3) Å; c = 15.1582(3) Å. The various types of hydrogen bonding interactions existing in the crystal structure of this salt were compared with the data of the previously reported polymorph. XRPD measurement proved that our salt consists of a pure phase of the new polymorph. Cooling down the salt to ca. 230 K caused its color to change from orange-brown to yellow. DSC experiments revealed that during the cooling an endothermic process takes place corresponding to the mentioned color change of the salt

Spectroscopic characterization and crystal structures of two cathinone derivatives : 1-(4-chlorophenyl)-2-(1-pyrrolidinyl)-pentan-1-one (4-chloro-α-PVP) sulfate and 1-(4-methylphenyl)-2-(dimethylamino)-propan-1-one (4-MDMC) hydrochloride salts, seized on illicit drug market

Purpose: Two compounds newly found in the seizures by drug enforcement agencies were identified and characterized by various instrumental analytical methods. Methods: The obtained powder samples were analyzed by gas chromatography–mass spectrometry (GC–MS), liquid chromatography–mass spectrometryn (LC–MSn), nuclear magnetic resonance (NMR) spectroscopy, infrared and Raman spectroscopy and X-ray crystallography. Results: The two compounds were tentatively identified as 4-chloro-α-PVP and 4-MDMC by GC–MS, and LC–MS/MS. The confirmation of the results was made by NMR spectroscopy. The X-ray crystallography gave information that 4-chloro-α-PVP and 4-MDMC were in salted forms with sulfate and hydrochloride, respectively; in addition, both compounds existed as racemic mixtures. Conclusions: We could identify 4-chloro-α-PVP and 4-MDMC in the seizure powder samples by various analytical methods. X-ray crystallography was especially useful for identifying the salted forms and enantiomeric forms