The crystal structure of C n mimNTf2 (n = 2, 4, 6) was studied for the first time simultaneously by X-ray diffraction method and IR spectroscopy. The temperature-dependent IR spectrum for crystalline ...C4mimNTf2 was demonstrated to correlate with both the X-ray data and the calorimetric results obtained earlier. Therefore, it was found that IR spectroscopy is able to establish the correspondence between the X-ray and the calorimetric data in this case. The joint use of X-ray diffraction, IR spectroscopy, and quantum-chemical calculations allowed us to determine the structure of all C2mimNTf2 crystalline modifications obtained earlier by adiabatic calorimetry measurements. Thus, a new approach for the future identification of ionic liquid crystal structure by use of temperature-dependent infrared spectroscopy is suggested and justified.
Wire Tension Test Bench for Wire Chambers Abazov, V. M.; Alexeev, G. D.; Golovanov, G. A. ...
Physics of particles and nuclei letters,
10/2022, Letnik:
19, Številka:
5
Journal Article
Recenzirano
A test bench for determining the wire tension of wire chambers was designed. The tension of the wires is checked by measuring the resonant frequencies of their vibrations. In this work the ...development of the key modules of the test bench and the corresponding software are presented. The results of the test stand performance during the production of detectors for the SPD Muon System Prototype (NICA/JINR) are presented.
The high-resolution X-ray diffraction analysis of the electron density distribution and plane-wave density functional theory has been applied to estimate the lattice energy and barrier to rotation of ...a benzene ring in the crystal of (η6-C6H6)2Cr. Experimental data made it possible to perform analysis of the metal−(π-ligand) bond and estimate the nature and energy of weak H···H and H···C intermolecular interactions in the crystal. Summation of the intermolecular H···H and H···C interaction energies makes it possible to reproduce the experimental sublimation enthalpy value with high accuracy.
Tetramethylcyclobutadiene(cyclopentadienyl)cobalt complexes Cb*Co(C5H4R) (Cb* = η4-C4Me4; R = H (5a), Me (5b), SiMe3 (5d), C(O)H (5f), and C(O)Me (5g)) were obtained by reaction of cyclopentadienide ...anions either with the (carbonyl)iodide complex Cb*Co(CO)2I (1) (method A) or with the more reactive acetonitrile complex Cb*Co(MeCN)3+ (2) (method B). Analogous compounds Cb*CoCp* (5c), Cb*Co(1,3-C5H3(SiMe3)2) (5e), and Cb*Co(η5-indenyl) (6) can be prepared only by method B. Treatment of 5f,g with NaBH4/AlCl3 or LiAlH4 affords the alkyl derivatives 5b and 5h (R = Et) or the alcohols 5i (R = CH2OH) and 5j (R = CH(OH)Me), respectively. The reaction of 1 with fluorene/AlCl3 yields complex Cb*Co(η6-fluorene)+ (8), which was deprotonated by KOBu t to give Cb*Co(η6-fluorenyl) (9). Visible light irradiation of 9 induces η6→η5 haptotropic rearrangement to afford Cb*Co(η5-fluorenyl) (7). The pyrrolyl and phospholyl complexes Cb*Co(C4R4N) (R = H (10a), Me (10c)) and Cb*Co(C4R4P) (R = H (11a), Me (11c); R4 = H2Me2 (11b)) were obtained by reaction of 2 with the corresponding pyrrolide or phospholide anions. Improved procedures for the preparation of the starting materials 1 and 2 were developed. Using a one-pot procedure, the iodide 1 was obtained in high yield from 2-butyne and Co2(CO)8. Complex 2 was prepared by heating or irradiation of the toluene complex Cb*Co(C6H5Me)+ (4b) in acetonitrile. Structures of 5g, 6, and 11c were investigated by X-ray diffraction. Electrochemistry and joint UV−visible and EPR spectroelectrochemistry of complexes prepared were studied.
The room-temperature photochemical reaction of the tricarbollide anion nido-7,8,9-C3B8H11- (1a) with CpFe(C6H6)+ proceeds without cluster rearrangement to form the 12-vertex closo-ferratricarbollide ...1-Cp-1,2,3,4-FeC3B8H11 (2a, the metal atom is assigned number 1). 2a rearranges to the isomeric complex 1-Cp-1,2,3,5-FeC3B8H11 (2b) at 110 °C and further to 1-Cp-1,2,4,10-FeC3B8H11 (2c) at 165 °C. The reaction of 1a with Cp*RuCl4 is accompanied by polyhedral rearrangement giving 1-Cp*-1,2,3,5-RuC3B8H11 (3b). Its further isomerization occurs slowly at room temperature and rapidly at 65 °C to give complex 1-Cp*-1,2,4,10-RuC3B8H11 (3c). Similar reactions of nido-7,8,10-C3B8H11- (1b) with CpFe(C6H6)+ and Cp*RuCl4 afford 2b and 3b, respectively. A diamond-square-diamond mechanism for the 2a → 2b → 2c rearrangement sequence is proposed. The relative stability of isomers 2a−c was estimated by DFT calculations. The constitution of the compounds prepared was determined by multinuclear NMR spectroscopy and mass spectrometry. The structures of 2a, 2b, and 3c were established by X-ray diffraction.
A room-temperature reaction between the 7- t BuNH-nido-7,8,9-C3B8H10- anion (1a) and Cp*RuCl4 leads to the ruthenatricarbollide 1-Cp*-12- t BuNH-1,2,4,12-RuC3B8H10 (2) (yield 85%). Analogously, the ...room-temperature photochemical reaction of 1a with CpFe(C6H6)PF6 gives the previously reported iron complex 1-Cp-12- t BuNH-1,2,4,12-FeC3B8H10 (3) (yield 82%). Both reactions are associated with extensive polyhedral rearrangement, which occurs under very mild conditions and brings the carbon atoms to positions of maximum separation within the framework. Compounds 2 and 3 were also surprisingly obtained via complexation of the isomeric 8- t BuNH-nido-7,8,9-C3B8H10- (1b) anion. Complex 2 rearranges further to 1-Cp*-10- t BuNH-1,2,4,10-RuC3B8H10 (4) upon refluxing in xylene (145 °C). Density functional theory calculations at the B3LYP/SDD level were used to estimate relative stabilities of these metallacarborane isomers. Compounds 2 and 4, along with the 11-vertex closo compounds 1-Cp*-1,2,3,10-RuC3B7H10 (5) and 1-Cp*-10- t BuNH-1,2,3,10-RuC3B7H9 (6), were also isolated from the reaction between Cp*RuCl22 and 1a in boiling xylene. The structure of 2 was established by an X-ray diffraction study, and the constitution of all compounds was determined unambiguously by multinuclear NMR spectroscopy, mass spectrometry, and elemental analyses.
It was discovered that bis-methylation of methano-Tröger base is smooth in pure dimethylsulfate, providing new, configurationally stable, bis-methylate
3a. Mono- and bis-methylates
2b and
3b of ...ethano-Tröger base were synthesized. The crystal structures of racemic ethano-Tröger base and of its enantiopure methiodide (+)-(5
R,11
R)-
2b benzene clathrate are also reported.
The cocrystal of organic compound dissolved in the ionic liquid (1-methyl-3-n-butyl imidazolium bromide) has been investigated for the first time using single crystal X-ray diffraction. The ...interactions between ionic solvent and solute were examined. It was shown that the general features of supramolecular organization of the solvent part remain the same as in the crystal of the pure ionic liquid.
