Reviews and Advances in Chemistry最新文献

Abstract

The structure of the tetra(p-tolyl)antimony compounds p-Tol₄SbX (X = Br (1), OC(O)Ph ∙ PhH (2), OSO₂C₆Me₃-2,4,6 (3)) is determined by X-ray diffraction analysis (XRD). According to the XRD data, the antimony atoms in complexes 1–3 exhibit a distorted trigonal bipyramidal coordination with three aryl ligands in the equatorial plane, and the axial angles CSbX are 174.75(8)°, 175.13(9)°, and 174.51(6)°, respectively.

The XRD data for compound 1 are as follows: C₂₈H₂₈BrSb, M = 566.16; monoclinic system, sp. gr. P2₁/n; cell parameters: a = 9.868(6) Å, b = 23.312(11) Å, c = 12.106(6) Å; β = 113.15(2)°, V = 2561(2) ų, Z = 4; ρ(calc.) = 1.469 g/cm³; μ = 2.649 mm^–1; F(000) = 1128.0; 2θ data acquisition region: 6.4°–56.76°; –13 ≤ h ≤ 13, –31 ≤ k ≤ 31, –16 ≤ l ≤ 16; total reflections 42 998; independent reflections 6359 (R_int = 0.0346); GOOF = 1.080; R factor 0.0325. For compound 2: C₄₁H₃₉O₂Sb, M = 685.47; monoclinic system, sp. gr. С2/с; cell parameters: a = 28.186(13) Å, b = 15.116(6) Å, c = 17.629(8) Å; β = 91.73(2)°, V = 7507(6) ų, Z = 8; ρ(calc.) = 1.213 g/cm³; μ = 0.765 mm^–1; F(000) = 2816,0; 2θ data acquisition region: 6.572°–56.996°; –37 ≤ h ≤ 37, –20 ≤ k ≤ 20, –23 ≤ l ≤ 23; total reflections 116 806; independent reflections 9489 (R_int = 0.0492); GOOF = 1.102; R factor 0.0363. For compound 3: C₃₇H₃₉O₃SSb, M = 685.49; monoclinic system, sp. gr. P2₁/n; cell parametrs: a = 12.172(4) Å, b = 18.802(5) Å, c = 15.433(6) Å; β = 108.744(12)°, V = 3345(2) ų, Z = 4; ρ(calc.) = 1.361 g/cm³; μ = 0.921 mm^–1; F(000) = 1408.0; 2θ data acquisition region: 5.96°–63.02°; –16 ≤ h ≤ 17, –27 ≤ k ≤ 27, ‒22 ≤ l ≤ 21; total reflections 138 835; independent reflections 11 081 (R_int = 0.0373); GOOF = 1.045; R factor 0.0304. Complete tables of atomic coordinates, bond lengths, and bond angles for compounds 1–3 have been deposited to the Cambridge Structural Database (CSD) with the following deposition numbers: 2182608, 2149953, and 2171918. For access to the data, please contact deposit@ccdc.cam.ac.uk or visit http://www.ccdc.cam.ac.uk.

Abstract

Cyanoaurate complexes represent a broad class of compounds with diverse structures. In particular, coordination polymers based on these complexes have numerous potential practical applications, including in microelectronics, nanotechnology, materials science, and medicine. In the development of new functional materials, significant attention is given to the possibility of molecules and other structural units participating in noncovalent interactions, which play a crucial role in determining the physicochemical properties and biological activity of these materials. Thus, the presence of aurophilic contacts or halogen–halogen interactions in cyanoaurate complexes only intensifies researchers’ interest in this class of compounds. At present, study of the chemistry of gold cyanides continues to develop rapidly, making the synthesis and exploration of new cyanoaurate compounds, as well as the systematization of the knowledge gained, relevant tasks. This review, encompassing a description of contemporary achievements in the methods of synthesis, investigation of structural features, and potential practical applications of metal dicyanoaurates, tetracyanoaurates, and dihalodicyanoaurates of both molecular and ionic types, is based on an analysis of publications, with the majority of sources published before 2022. Some more recent studies are also included in the review. The information presented in this article is fundamentally important and undoubtedly valuable for specialists in the field of inorganic and organometallic chemistry of gold.

Abstract

The report describes the synthesis of a series of new imidazolinones-2, imidazole-2-thiones, and 1,3-oxazoles based on the interaction of 1-bromo ketones containing a diterpene fragment with urea and thiourea. It is shown that the direction of the reaction and the yields of the products depend on the nature of the initial substrates and the conditions of the reaction. For instance, boiling bromides with ureas or thiourea in ethyl alcohol in the presence of sodium carbonate leads to nucleophilic substitution, forming diterpene-substituted ureas. Performing the same reaction in ethylene glycol at a temperature of 200–250°C in the presence of potassium hydroxide results in the formation of imidazolin-2-ones or -thiones containing the diterpene fragment at the 4-position with high yields.

Abstract

We investigated the complexation reaction of N-benzoyl-N'-(phenylsulfonyl)hydrazine with Cu(II) ions in an ammonia medium. The absorption spectra of the reagent and its complex compound with Cu(II) ions were recorded and analyzed. Optimal conditions for complex formation were determined, including the pH range for complexation, the optimal time for color development, and the amount of photometric reagent. Under optimal conditions, a calibration curve for the complexation of BFSH with Cu(II) ions was plotted. The Beer–Lambert–Bouguer law is valid in the range from 0.5 to 1.75 mg of Cu(II) in 25 mL of the solution. The true (19 389 cm²/mol) and apparent (4708 cm²/mol) molar absorption coefficients were calculated. Using the methods of saturation, equilibrium shift, curve intersection, isomolar series, and conductometric titration, the molar ratios in the solution of the complex compound were determined as [Cu(II)] : [BFSH] = 1 : 1 and 1 : 2. The conditional stability constant of the complex, calculated using the Babko method, is 2.45 × 10¹³. The convergence and accuracy of the spectrophotometric method were determined statistically.

Abstract

The review focuses on the latest advancements in chlorine-free oxidizers for solid rocket propellants as of January 1, 2023. The properties and applications of phase-stabilized ammonium nitrate, ammonium dinitramide, and compounds with trinitromethyl and trinitroethyl groups as high-density explosive materials, plasticizers, and components of solid rocket propellants are discussed. Formulations of rocket propellants containing these components, along with their physicomechanical properties, ballistic characteristics, and chemical stability indicators, are presented.

Abstract

We present the results of the investigation of the physicochemical properties of oxalic acid N'-tosylhydrazide ethyl ester (THE). The solubility of the reagent was examined in ethanol, 0.1 mol/L KOH solution, toluene, chloroform, hexane, and water using spectrophotometry, refractometry, and gravimetry. The results suggest that THE can be useful in flotation and extraction processes. Acid–base equilibria in the reagent solutions were studied by spectrophotometric methods. The obtained dissociation constants (pK_a1 = 7.56 ± 0.14; pK_a2 = 13.48 ± 0.22) confirm that THE is a weak dibasic acid. The hydrolytic stability of the reagent was investigated spectrophotometrically. The research findings indicate that THE solutions are sufficiently stable over time in alkaline media, with a hydrolysis rate of 4.77% over 2 h. The surface activity of the reagent was determined by the stalagmometric method, revealing that THE is a surfactant.

Abstract

Eye drops represent the traditional form of medication delivery for the eyes, constituting approximately 90% of the presently available ophthalmic formulations. While they are generally well-received by patients, a significant challenge associated with eye drops is the rapid loss of medication before it reaches the cornea. The creation of new systems and means of drug delivery is important for solving the main problems of medicine – improving the therapeutic efficiency, tolerability, and safety of medical therapy. In the treatment of numerous of eye diseases, the main problem is creating a constant and sufficient concentration of drugs in the lesion due to the peculiarities of the anatomical and physiological structure of the eyeball. New approaches to non-invasive drug delivery are being developed, such as eye implants, contact lenses, as well as drug delivery systems based on nanoparticles, micelles, dendrimers, microneedles and liposomes. In situ gelation systems are also the subject of study and promising developments. Combining drugs within conventional delivery systems has the potential to pave the way for enhanced outcomes and improved therapeutic responses, particularly for systems that have previously shown limited effectiveness. This review discusses current understanding and recent discoveries attributed the utilisation of drug delivery systems in ophthalmology, including the characteristics, advantages, and disadvantages of each class of delivery system.

Abstract

Here we present the literary review concerning methods of synthesis and application fields of substituted quinophthalones, an interesting class of heterocyclic compounds containing fragments of substituted/unsubstituted quinolines and phthalic anhydride in their structure. Such compounds have an extended π-conjugated system and are, therefore, most often used as dyes.

Abstract

Interaction of pentafluorophenyl- and penta(para-tolyl)antimony with ferrocenedicarboxylic acid (molar ratios 1 : 1 and 2 : 1) in toluene (20°C, 24 h) results in the substitution of hydrogen in one or two carboxylate groups, leading to the formation of ferrocenecarboxylates of tetraaryl antimony HOOCС₅H₄FeС₅H₄C(O)OSbPh₄ (1), HOOCС₅H₄FeС₅H₄C(O)OSbTol₄ (2), Ph₄SbC(O)OС₅H₄FeС₅H₄C(O)OSbPh₄ (3) and p-Tol₄SbC(O)OС₅H₄FeС₅H₄C(O)OSbTol₄ (4) with yields up to 83%. Compounds 1−4 were identified by elemental analysis, IR spectroscopy, and X-ray diffraction analysis for 4. The XRD analysis of complex 4 was conducted on an a D8 Quest Bruker automatic four-circle diffractometer (Мо K_α radiation, λ = 0,71073 Å, graphite monochromator) at 293 K. Crystallographic characteristics of 4: monoclinic syngony, space group P2₁/c, a = 17.227(17) Å, b = 11.064(9) Å, c = 30.59(3) Å, β = 100.00(4)°, V = 5742(9) ų, Z = 4, ρ_calc = 1.440 g/cm³, 2θ 6.02°−49.08°, 124 343 total reflections, 9436 independent reflections, number of refined parameters 684, R_int = 0.1051, GOOF 1.094, R₁ = 0.0536, wR₂ = 0.1309, residual electron density (max/min) 0.88/–1.21 e/ų. According to XRD analysis, the coordination of antimony atoms in crystal 4 is distorted octahedral due to the bidentate chelating nature of the carboxylate ligand. Diagonal angles in the two octahedra are 146.4(2)°, 154.0(3)°, 171.0(2)° and 147.4(2)°, 154.8(2)°, 166.9(2)°. The Sb−О distances are 2.296(5), 2.502(5) Å and 2.289(5), 2.453(5) Å, while the Sb−С bonds differ significantly, 2.146(7)−2.166(7) and 2.123(6)−2.165(7) Å. The structural organization of the crystal is mainly governed by С−Н···π interactions.

Abstract

Photoinduced polymerization of Langmuir–Schaefer monolayers of four unsymmetrical hydroxyalkadiynyl N-arylcarbamate derivatives, prepared on the basis of diynes solutions with an extremely low concentration, was studied under prolonged UV irradiation. The kinetics of these diacetylene (DA) molecules films transition to the blue phase of polydiacetylenes (PDA) films, which is not characteristic of any other DA alcohol derivatives, has been studied by light absorption spectroscopy and scanning electron microscopy. The structure homogeneity of DA and PDA films was demonstrated. A continuous shift of the optical absorption band of each PDA film to the long-wavelength region of the spectrum during 60 min of UV light irradiation was found. That indicated an increase of the chains conjugation length in blue-phase PDA samples.