Hydrated Dodecatungstatosilicate Complex with Protonated 1,2-Phenylenediamine (C6H9N2)3(H3O)SiW12O40 · 8H2O: Synthesis and Crystal Structure

The hydrated dodecatungstatosilicate complex with protonated ortho-phenylenediamine (C6H9N2)3(Н3O)SiW12O40 · 8H2O has been synthesized and studied by X-ray diffraction. Crystals are triclinic, space group Р-1, a = 13.6817(5) Å, b =1 4.5915(5) Å, с = 15.8844(5) Å, α = 98.891(3)°, β = 101.836(3)°, γ = 114.156(2)°, V = 2729.05(16) Å3, ρcalcd = 4.100 g/cm3, Z = 2. © 2018, Pleiades Publishing, Ltd

POTENTIOMETRIC DETERMINATION OF REDOX POTENTIALS OF SYSTEM: THIUREA AND SOME OF ITS N-SUBSTITUTED

The redox systems of thiourea (Tu, RS), thiosemicarbazide (Tsc), N-phenylthiourea (Phtu), N-acetylthiourea (Atu) and their oxidized form (formamidine disulfide derivatives, RSSR2+) were studied in HCl at t = 25.0 +/- 0.1 degrees C. To determine the reversibility of the processes in the system (RSSR2+ + RS + 1 M HCl) and to form the corresponding disulfides, iodine solution (I-2) and hydrogen peroxide were used as oxidants. When RS is oxidized, equilibrium is established in the system according to the equations: 2 RS - 2 e = RSSR2+. The witnesses of the equations are the slope of the electrode function theta (theta = 2.3 RT/nF), which corresponds to n = 2, that is, each R=S molecule donates one electron. The oxidation reaction with hydrogen peroxide is slow. The values of the conventional standard potential of the redox system "RSSR2+ / RS - 1 mol/l HCl" have been determined. It was found that in the oxidized form thiourea and thiosemicarbazide exhibit a stable reproducible potential, while formamidine disulfide derivatives of N-phenylthiourea and N-acetylthiourea are unstable and after 30-60 min decompose with the formation of elemental sulfur and other products. Therefore, for these systems, only solution I-2 was used as an oxidizing agent. The oxidized form of thiosemicarbazide (Tsc) (diamminoformamidine disulfide, H(2)Damfds(2+)) remains in solution for up to 4 h, after which the appearance of colloidal sulfur is observed. Note that the decomposition of the oxidized form of Phtu and Atu depends on their concentrations: an increase in the concentration of the oxidized form in solution leads to a decrease in its stability

Hydrated Dodecatungstatosilicate Complex with Protonated 1,2-Phenylenediamine (C6H9N2)3(H3O)SiW12O40 · 8H2O: Synthesis and Crystal Structure

The hydrated dodecatungstatosilicate complex with protonated ortho-phenylenediamine (C6H9N2)3(Н3O)SiW12O40 · 8H2O has been synthesized and studied by X-ray diffraction. Crystals are triclinic, space group Р-1, a = 13.6817(5) Å, b =1 4.5915(5) Å, с = 15.8844(5) Å, α = 98.891(3)°, β = 101.836(3)°, γ = 114.156(2)°, V = 2729.05(16) Å3, ρcalcd = 4.100 g/cm3, Z = 2. © 2018, Pleiades Publishing, Ltd

Study of Silver(I) Complex Formation with Some Thiourea Derivatives in Aqueous Solution

Abstract: The equilibrium processes of the formation of mononuclear and some binuclear silver(I) complexes with thiourea, N-acetylthiourea, thiosemicarbazide, N-phenylthiourea, and N,Nʹ-diphenylthiourea at 25°C and I = 0.11 M. (0.01 M HNO3 + 0.1 M NaNO3) in aqueous solution were studied by potentiometry method with a silver electrode. The stability constants of the complexes were determined. The stability of mononuclear complexes is almost identical for all the ligands, except for complexes with acetylthiourea, for which it is lower. © 2020, Pleiades Publishing, Ltd

Synthesis and characterization of the acid hexamolybdocobaltate(III) complex with amino acid glycine of composition (H3O)3[CoMo6O18(OH)6]•(H3NCH2COO)2(H2O)5

The hydrated acid hexamolybdocobaltate(III) complex with the amino acid glycine of composition (H3O)3[CoMo6O18(OH)6]•(H3NCH2COO)2(H2O)5 was synthesized. The structure of the new complex was established by single-crystal X-ray diff raction, powder X-ray diff raction, IR and NMR spectroscopy. © 2020, Springer Science+Business Media LLC

Effect of Temperature on the Stability of Mononuclear and Binuclear Silver(I) Complexes with Thiourea and N-Phenylthiourea in Aqueous Solutions

Abstract: A potentiometric study is conducted of equilibria of the formation of silver(I) complexes with thiourea and N-phenylthiourea (L) using a silver electrode in the 278.16–318.16 K range of temperatures at an ionic strength of I = 0.11 M (0.1 NaNO3 + 0.01 HNO3). It is found that mono- and binuclear complexes are present in the studied systems in a wide range of concentrations of Ag+ ions (1 × 10−5–1 × 10−3) in solution at different temperatures, and the Ag2L32+ form dominates in both systems. It is shown that the stability of mono- and binuclear complexes falls as the temperature rises. Thermodynamic parameters (ΔH°, ΔG°, and ΔS°) are determined for mononuclear complexes. © 2022, Pleiades Publishing, Ltd

Синтез и исследование гексамолибдохромата пиридин-3-карбоновой кислоты состава(С6H5NO2)2[H3O]4[CrMo6O18(OH)6].4Н2О

The Chemistry of heteropoly compounds (HPC) is one of the modern direction of Coordination chemistry. In current times, the high importance in the development of HPC chemistry is the synthesis of new hybrid, organic-inorganic heteropolystructures with preassigned physicochemical properties as well as the determination of common factors of change in these properties depending on the composition and structure. The X-ray diffraction study of the obtained compounds has showed that the packing of molecules into crystals is carried out with the formation of through channels along the c axis, which can play a significant role, for example, during catalytic processes. The ability of natural nicotinic acid to form complexes with heteropolyanion [CrMo6(ОН)6O18]4- is known. The high biological activity of nicotinic acid, as well as the activity of a number of polymetallates to the suppression of certain types of viruses which was described in the literature, make it possible to consider hybrid materials based on these substances promising from the point of view of the consciousness of new pharmaceuticals. Based on this data, we have synthesized pyridine-3-carboxylic acid hexamolybdochromate of composition (С6H5NO2)2[H3O]4[CrMo6O18(OH)6].4Н2О. The compound was studied by chemical, X-ray diffraction, thermogravimetric, NMR and IR spectroscopic methods of analysis. It is established that the synthesized compound crystallizes in triclinic syngony with unit cell parameters: а = 9.1640(8)Å, b = 10.6441(11)Å, с = 10.8241(12)Å; α = 95.968(10)°, β = 109.864(12)°, γ = 105.059(11)°; calc .= 2.502 g/cm3, V = 937.2(2) Å3; Z = 1.Химия гетерополисоединений (ГПС) - одно из современных направлений координационной химии. В настоящее время большое значение в развитии химии ГПС имеет синтез новых гибридных, органо-неорганических гетерополиструктур с заданными физико-химическими свойствами, а также определение закономерностей изменения этих свойств в зависимости от состава и строения. Рентгеноструктурное исследование полученных соединений показало, что упаковка молекул в кристаллы осуществляется с образованием сквозных каналов вдоль оси с, что может играть существенную роль, например, при проведении каталитических процессов. Известна способность природной никотиновой кислоты образовывать комплексы с гетерополианионом [CrMo6(ОН)6O18]4-. Высокая витаминная биологическая активность никотиновой кислоты, а также описанная в литературе активность ряда полиметаллатов в отношении подавления некоторых видов вирусов, позволяют рассматривать гибридные материалы на основе этих веществ перспективными с точки зрения сознания новых лекарственных препаратов. Основываясь на этих данных нами синтезирован гексамолибдохромат пиридин-3-карбоновой кислоты состава (С6H5NO2)2[H3O]4[CrMo6O18(OH)6].4Н2О. Соединение исследовано химическим, рентгено-структурным, термогравиметрическим, ЯМР и ИК-спектроскопическими методами анализа. Установлено, что синтезированное соединение кристаллизуется в триклинной сингонии с параметрами элементарной ячейки: а = 9.1640(8)Å, b = 10.6441(11)Å, с = 10.8241(12)Å; α = 95.968(10)°, β = 109.864(12)°, γ = 105.059(11)°; (выч.).= 2.502 г/см3, V = 937.2(2) Å3; Z = 1. На основании полученных результатов и анализа литературных данных можно сделать вывод об отсутствии большого влияния органического фрагмента на структуру гетерополианиона, однако характер его определяет способ упаковки молекул в кристалле