Because of the high cost of corrosion-resistant steels, a necessary condition for their production is reducing rejection at all stages of processing, including hot forming, by optimizing process ...parameters. In this work, the mechanical characteristics of a corrosion-resistant steel with high content of boron have been studied at elevated temperatures. Using a special complex for the physical simulation of thermomechanical processes, it has been shown that the optimum temperature range of hot compressive plastic deformation is 950–1100°C. A mathematical model has been constructed, which relates the yield stress to the parameters of the process of hot plastic deformation. During deformation in the range of 850–1150°C, the boride particles present in the steel become oriented perpendicular to the compression axis; at high temperatures, the spheroidization of titanium diborides occurs, which reduces their size.
Solid-state photochromic indoline spiropyrans bearing a formyl group at the 6′ and 8′ positions of the 2
H
-chromene moiety of the molecules were characterized. The molecular structures of ...spiropyrans were established by single-crystal X-ray diffraction. Intermolecular interactions and voids in the crystals were investigated using the CrystalExplorer17 software package. Further studies of photochromism and mechanochromism of these spiropyrans in the crystalline state are shown to be promising.
The work discusses the mechanism of the formation of by-products during the synthesis of spiropyrans based on 1,3-benzoxazin-4-one heterocycle as a result of the hydrolysis of intermediate styryl ...salt, which explains the low yields of this class of compounds. The structures of the isolated by-products were confirmed by IR and NMR spectroscopy using 2D homo- and heteronuclear experiments, as well as by elemental analysis.
The structure and mechanical properties of steel with an elevated content of boron are studied after tensile tests at a high temperature. In its initial condition, the structure of the steel contains ...two types of borides TiB
2
and (Fe, Cr)
2
B distributed uniformly in a ferritic matrix. The range of satisfactory process ductility is shown to be 1050 – 1150°C; at 1200°C the metal undergoes brittle fracture due to local fusion of individual regions of the structure.
Two new photochromic spiropyrans containing carboxyl groups in the hetarene part of the molecule and being of interest as modifiers of organometallic scaffolds to give them photo-controlled functions ...are obtained by the cyclocondensation reaction of 5-carboxy-1,2,3,3-tetramethyl-3
H
-indolium iodide with corresponding 2,4-diformylphenols. The structure of the compounds obtained is confirmed by infrared (IR),
1
H and
13
C NMR spectroscopy (using
1
H–
1
H COSY,
1
H–
13
C HSQC,
1
H–
13
C HMBC, and
1
H–
15
N HMBC 2D NMR techniques); the chemical composition is determined by elemental analysis. The diffraction patterns of powdered samples of the compounds are measured, which make it possible to determine the symmetry groups and unit-cell parameters. Photochemical studies reveal the photochromic properties of the compounds at room temperature, and measurement of the rate constants
k
BA
of the thermal discoloration of merocyanine forms at different temperatures allowed us to calculate the activation energy of these processes.
The new spiropyran systems with an azomethine bridge were synthesized from a spiropyran containing aminogroup at 6′ position of the benzopyran fragment and substituted aromatic aldehydes. The ...chemical structure of compounds is confirmed by elemental analysis data, NMR (
1
H and
13
C) and IR spectroscopy. Photochemical studies revealed the presence of photochromic properties at room temperature for one of the obtained spiropyrans.
Cyclocondensation of gossypol, the pigment of Gossypium (cotton), and Fischer’s bases produced two new spirocyclic compounds with potentially combined pharmacological and photoswitching activities. ...The structures and photochemical properties of the synthesized compounds were studied using PMR, IR, and UV spectroscopy.
The computational simulation of structure, energy and spectral characteristics of spiropyrans and their complexes with the cluster containing ten silver atoms was carried out using the density ...functional theory method (B3LYP/6-31G(d,p)/SDD). A competitive coordination of oxygen-containing substituents in the indoline and benzopyran moieties in spirocyclic molecules to the metal atoms was studied and an effect of position of donor groups on the activity of CO vibrational bands was established in the calculated Raman spectra. We revealed compounds, whose
trans-trans-trans
isomers upon a complexation with the silver cluster are characterized by the more than 100 times enhanced activity of band associated with the valence vibrations of CO bond in the Raman spectrum.
A comparative analysis is performed for the stress flow models of a steel containing 2.3 wt % B during its compressive hot deformation based on an Arrhenius-type equation and artificial neural ...networks. It is shown that the accuracy of the obtained data using the model based on artificial neural networks is much higher (relative calculation error is 0.2%) as compared to that of the regression model (relative error is 11%).
A polyfunctional spiropyran of 1,3-benzoxazin-4-one series containing one hydroxy and two carbonyl substituents in the 2H-chromene moiety was synthesized on the basis of a new analogue of ...2,4-dihydroxyisophthalic aldehyde, methyl 3,5-diformyl-2,4-dihydroxybenzoate. The structure of resulting 6'-carbomethoxy-3,7-dimethyl-8'-formyl-5'-hydroxy-4-oxo-spiro-(1,3-benzoxazine-2,2'-2
H
-chromene) was unambiguously established by single crystal X-ray diffraction analysis. These data allowed us to reveal the route for the reaction of the new polyfunctional aldehyde with 1,3-benzoxazin-4-onium perchlorate.
