Complex formation of vanadium(V) with 4-(2',3',4'-trihydroxyphenyl)-3-nitro-5-sulfoazobenzene (R) in the presence of cationic surfactants (CS), cetylpyridinium chloride (CPCl), cetylpyridinium bromide (CPBr), and cetyltrimethylammonium bromide (CTMABr), is studied. Vanadium(V) and R form a colored complex at a component ratio of 1 : 2 and pH of 5.0–5.5. The absorbance maximum of the complex is at 449 nm, while the reagent under these conditions absorbs light at 395 nm. In the presence of cationic surfactants, mixed-ligand complexes with a component ratio of V(V) : R : CS = 1 : 2 : 2 are formed, which results in a bathochromic shift of the absorbance maximum. Additionally, the pH value for the maximum complex formation shifts to a more acidic medium compared to the homoligand V(V)–R complex. The absorbance of the V(V) : R : CPCl, V(V): R : CPBr, and V(V) : R : CTMABr complexes is maximal at 457, 461, and 466 nm, respectively. The yield of these complexes is the highest at pH of 3.5–4.0 for VV(V) : R : CPCl and V(V): R : CPBr, and at a pH of 2.5–3.0 for V(V) : R : CTMABr. The formation of both homoligand and mixed-ligand vanadium(V) complexes depends on the reaction time, temperature, and concentrations of the reacting components. The determined stability constants indicate the high stability of the resulting mixed-ligand complexes. The specific conductivity of the complexes under the optimal conditions of complex formation was determined using conductometric titration. Calibration curves for the determination of vanadium(V) as homoligand and mixed-ligand complexes are linear. The effect of foreign ions and masking agents on the determination of V(V) as homoligand and mixed-ligand complexes was analyzed; it was shown that the presence of cationic surfactants significantly increases the selectivity of the reaction. An analysis of water samples from Lake Khanbulan, Lankaran District, Azerbaijan Republic using the developed procedure showed the presence of small amounts of vanadium(V).

Исследована возможность экстракции комплекса никеля(II) с 1-(2-алиламино-1-метилэтил)тиокарбамидом в присутствии и в отсутствие гидрофобных аминов- дифенилгуанидина и трифенилгуанидина. Установлено, что в присутствии гидрофобных аминов образуются смешанолигандные комплексы, хорошо растворимые в бутаноле-1. Извлечение комплексов происходит в течение 60 с, разделение фаз занимает 80 с. Однократной экстракцией извлекается до 96.7 и 98.0% никеля(II) в присутствии дифенилгуанидина и трифенилгуанидина соответственно. Установлены оптимальные условия образования и экстракции комплексов никеля(II) в присутствии и в отсутствие гидрофобных аминов. Определено соотношение компонентов в составе комплексов, установлен интервал линейности градуировочного графики для определения никеля(II) (0.10–2.80 мкг/мл) и получены уравнения градуировочных графиков по методу наименьших квадратов. Изучено влияние посторонних ионов и маскирующих веществ на экстракционно-спектрофотометрическое определение никеля(II) и установлено, что за счет образования смешанолигандных комплексов значительно увеличивается избирательность реакции. Разработана методика экстракционно-спектрофотометрического определения микроколичеств никеля в водах рек Акстафа и Джогаз Казахского района Азербайджанской Республики.

The effect of the third components of cationic surfactants – chloridecetylpyridinium (CPCl), cetylpyridinium bromide (CPBr), cetyltrimethylammonium bromide (CPMABr) for complexation of nickel (II) with 4- (2´, 3´, 4´-trihydroxyphenyl) -3-sulfo-5-chlorophenylazo benzene (R). Same- (NiR) and mixed-ligand complex compounds (Ni (II) -RCPCl, Ni (II) -RCPBr and Ni (II) -RCPMABr) are formed at pH 6, 4, 4 and 4, respectively. All complexes are formed immediately after mixing the solutions of the components and differ in stability. The ratio of the reacting components in the composition of same- (1: 1) and mixed-ligand (1: 1: 1) complexes are established. The interval of obedience to Beer's law is determined. The coefficients of the calibration curve equation are determined by the method of least squares. Complexation of nickel (II) is expressed by linear dependence of A = f (c) is. Stability constants of same- (NiR) and mixed-ligand complexes (Ni (II) -RCPCl, Ni (II) -RCPBr and Ni (II) -RCPMABr) are calculated. Under optimal conditions of complexation, Ni-R was titrated with a solution of third components (CPCl, CPBr and CPMABr) by conductometric method. The influence of foreign ions on complexation of nickel (II) with R in the absence and in the presence of third components was studied. A technique has been developed for the spectrophotometric determination of microquantities of nickel in the waters of the Akstafa and Jogaz rivers of the Kazakh region of the Republic of Azerbaijan

A possibility of extracting nickel(II) complex with 1-(2-allylamino-1-methylethyl)thiocarbamide in the presence and absence of hydrophobic amines, diphenylguanidine and triphenylguanidine, was studied. It was found that, in the presence of hydrophobic amines, mixed ligand complexes formed, which are readily soluble in 1-butanol. The extraction of complexes occurred within 60 s, phase separation took 80 s. A single extraction recovered up to 96.7 and 98.0

The effect of the third components of cationic surfactants - chloridecetylpyridinium (CPCl), cetylpyridinium bromide (CPBr), cetyltrimethylammonium bromide (CPMABr) for complexation of nickel (II) with 4- ( 2', 3', 4'-trihydroxyphenyl) -3-sulfo-5-nitrophenylazo benzene (R). Same- (NiR) and mixed-ligand complex compounds (Ni (II) -RCPCl, Ni (II) -RCPBr and Ni (II) -RCPMABr) are formed at pH 6, 3, 3 and 4, respectively. All complexes are formed immediately after mixing the solutions of the components and differ in stability. The ratio of the reacting components in the composition of same- (1: 1) and mixed-ligand (1: 1: 1) complexes are established. The interval of obedience to Beer's law is determined. The coefficients of the calibration curve equation are determined by the method of least squares. Complexation of nickel (II) is expressed by linear dependence of A = f (c) is. Stability constants of same- (NiR) and mixed-ligand complexes (Ni (II) -RCPCl, Ni (II) -RCPBr and Ni (II) -RCPMABr) are calculated. Under optimal conditions of complexation, Ni-R was titrated with a solution of third components (CPCl, CPBr and CPMABr) by conductometric method. The influence of foreign ions on complexation of nickel (II) with R in the absence and in the presence of third components was studied.

The interaction of Ti(IV) with 4-(2',3',4'-trihydroxyphenyl)-2-nitro-1-sulfoazobenzene (H3L) in the presence and in the absence of cationic surfactants (CAS) (cetylpyridinium chloride (CPCl), cetylpyridinium bromide (CPBr), cetyltrimethylammonium bromide (CTMABr)) was studied. The interval of concentration obeying Beer's law is established. In the complex formation of titanium(IV), the dependence A = f(C) is expressed by linear equations. The effect of time and temperature has been studied. The stability constants of binary and mixed-ligand titanium(IV) complexes were calculated. The ratio of the reacting components in the binary complex is 1:2, and in the mixed ligand 1:2:2. The effect of foreign ions and masking substances on the complex formation of titanium(IV) with reagents has been studied. Alkaline, alkaline earth and some transitional elements practically do not interfere to the determination. A technique has been developed for the spectrophotometric determination of titanium(IV) in aluminum-based standard samples

The article considers the interaction of Ti(IV) with 2, 3, 4-trihydroxy-3'-fluoroazobenzene (H3R) in the presence and absence of phenontroline (Phen), α, α'-dipyridine (α, α'-dip), and batophenontroline (B-phen) studied by using a spectrophotometric method. It has been found that the yield of the binary complex is maximum at pHopt = 5 (λmax = 428 nm), and for mixed-ligand complexes, pHopt = 3.0; 4.0; 3.5; λmax = 477 nm, 443 nm, 440 nm Ti(OH)2(H2R)-Phen, Ti (OH)2(H2R)-α, α'-dip and Ti(OH)2(H2R)-B-phen, respectively. It has been investigated that a twofold excess of the reagent is required for complete binding of titanium(IV) into the complex. The influence of time and temperature on the complexation is investigated. The stability constants of binary and mixed-ligand titanium(IV) complexes were calculated: logβ = 8.61 ± 0.05 for Ti(OH)2(H2R)2, logβ = 10.98 ± 0.06 for Ti(OH)2(H2R)-Phen, logβ = 10.85 ± 0.04 for Ti (OH)2(H2R)-α, α'-dip, logβ = 11.26 ± 0.03 for Ti(OH)2(H2R)-B-phen. The ratio of the reacting components in the binary complex is 1 : 2, and in the mixed ligands 1 : 2 : 2. The influence of foreign ions and masking substances on the titanium(IV) complexation with reagents has been studied. The determination is practically not interfered by alkaline, alkaline-earth and some transition elements. Due to these characteristics, the complexes can be used for defining titanium(IV) in different objects.

We studied the complexation of titanium(IV) with 2,2',3,4-tetrahydroxy-3'-nitro-5'-sulfoazobenzene (R) in the presence of cationic surfactants (CSs) cetylpyridinium chloride (CPCl), cetylpyridinium bromide (CPBr), and cetyltrimethylammonium bromide (CTMABr). In the presence of cationic surfactants, mixed-ligand complexes are formed with the ratio of components $${\text{Ti}}({\text{OH}})_{{\text{2}}}^{{{\text{2}} + }}$$ : H4R– : CS = 1 : 2 : 2. The optimal pH values of the complex formation were found: 4.5 for ( $${\text{Ti}}({\text{OH}})_{{\text{2}}}^{{{\text{2}} + }}$$ (H3R2–)2 and 3.5 for mixed-ligand complexes ( $${\text{Ti}}({\text{OH}})_{{\text{2}}}^{{{\text{2}} + }}$$ (H3R2–)2(CPCl)2, ( $${\text{Ti}}({\text{OH}})_{{\text{2}}}^{{{\text{2}} + }}$$ (H3R2–)2(CPBr)2, and ( $${\text{Ti}}({\text{OH}})_{{\text{2}}}^{{{\text{2}} + }}$$ (H3R2–)2(CTMABr)2. We also investigated the effect of time, temperature, and concentrations of the reacting components on the formation of mixed-ligand complexes. The Beer law is observed in the concentration range of ( $${\text{Ti}}({\text{OH}})_{{\text{2}}}^{{{\text{2}} + }}$$ (H3R2–)2, ( $${\text{Ti}}({\text{OH}})_{{\text{2}}}^{{{\text{2}} + }}$$ (H3R2–)2(CPCl)2, ( $${\text{Ti}}({\text{OH}})_{{\text{2}}}^{{{\text{2}} + }}$$ (H3R2–)2(CPBr)2, and ( $${\text{Ti}}({\text{OH}})_{{\text{2}}}^{{{\text{2}} + }}$$ (H3R2–)2(CTMABr)2 of 0.10–1.8, 0.10–1.92, 0.10–1.92, and 0.08–1.92, respectively. The effect of foreign ions and masking substances on the determination of titanium(IV) as mixed-ligand complexes was studied. We developed a procedure for the spectrophotometric determination of trace amounts of titanium in sea sand taken from the Caspian Sea coast near the Turkan village.

The effect of various components, including alpha,alpha'-dipyridyl (alpha,alpha'-dip), phenanthroline (Phen) and bathophenanthroline (B-phen), on the complexation of Ni(II) with 1,3-diphenyl-2-(2-hydroxy-4-nitrophenylhydrozo)propodion-1,3 (R) was studied. Homogeneous (Ni(II)-R) and mixed-ligand (Ni(II)-R-alpha,alpha'-dip, Ni(II)-R-Phen and Ni(II)-R-B-phen) complex compounds are determined to form at pH = 6, 5.5 and 5, respectively. The yield of the Ni(II)-R complex is established to be maximal at R concentration of 8.10(-5) M; Ni(II)-R-alpha,alpha'-dip - at concentration R and alpha,alpha'-dip of 8.10(-5) and 5.2.10(-5) M, respectively; Ni(II)-R-Phen - at concentration R and Phen of 8.10(-5) and 4.8.10(-5) M, respectively; Ni(II)-R-B-phen - at concentration of R and B-phen 8.10(-5) and 4.10(-5) M, respectively. All complexes, which differ in stability, were determined to form immediately after mixing the solutions of the components. The ratio of reacting components in the composition of homogeneous (1:2) and mixed (1:2:1) ligand compounds is established in terms of conformity to Beer's law. The equation coefficients for the calibration curve were obtained by the method of least squares. In the complexation of nickel(II), the. = f(c) dependence was shown to be expressed by linear equations. The stability constants of homogeneous (Ni(II)-R) and mixed-ligand (Ni(II)-R-alpha,alpha'-dip, Ni(II)-R-Phen and Ni(II)-R-B-phen) complexes were calculated. Under optimal complexation conditions, Ni(II)-R was titrated with a solution of the components, including alpha,alpha'-dip, Phen and B-phen, using the conductometric method. The effect of foreign ions on the complexation of nickel(II) with R both in the absence and presence of other components was studied. In the presence of other components, the selectivity of complexation reactions was established to increase significantly. These reagents were proved to be more selective for spectrophotometric determination of nickel(II) in comparison with reagents known from the literature. The developed technique was applied for nickel(II) determination in three varieties of apples.

Complex formation of cobalt(II) with 2-[2-dihydroxy-3,5-disulphenylазо]naphthalene-1,8-dihydroxy-3,6disulphosodium has been investigated in the presence and absence of surfactants-cetylpyridinium chloride, cetylpyridinium bromide, cetylpyridiniumtrimethylammonium bromide.Molar absorbtivities and stability constants of complexes have been determined.The determined concentration interval obeys to Beer's law.The developed technique was applied to determine cobalt(II) in the Akstafa and Jogaz rivers of the Kazakh region of the Azerbaijan Republic.Keywords cobalt(II), surfactants, cetylpyridinium chloride, cetylpyridinium bromide, cetyltrimethylammonium bromide, complexes of cobalt(II).

This article presents a study on the complexation of copper (II) with 2,7-bis(azo-2-hydroxy-3-sulfo-5-nitrobenzene)-1,8-dihydroxynaphthalene-3,6-disulphonosodium salt (R) in the presence of diphenylguanidine (DPG), triphenylguanidine (TPG) and non-ionic SAA Triton X-114 (TX-114), carried out by spectrophotometric method. The optimal conditions for the Cu-R complexation are established as follows: pH=3 with the maximum light absorption of the complex occurring at a wavelength of 538 nm. The yield of the Cu-R complex reaches a maximum at the R component concentration of 8.10(-3) M, while the highest value for Cu-R-DPG complex is observed at concentrations of 8.10(-5) and 1.10(-3) M for the R and DPG components, respectively. The maximum of Cu-R-TFG is noted with concentrations of the R and TPG components comprising 8.10(-5) and 8.10(-4) M, respectively. The maximum yield of the Cu-R-TritonX-114 complex was obtained at a component concentration of 8.10(-5) and 8.10(-4) M, respectively. All complexes are formed immediately following the mixing of the component solutions and differ in stability. In the presence of a third component, the maximum absorption is observed at a wavelength of 512 nm (pH=1), 491 nm (pH=2) and 572 nm (pH=2) for the Cu-R-TX-114, Cu-R-DPG and Cu-R-TPG complex, respectively. The reaction ratio of components in the composition of homogeneous (Cu:R =1:2) and mixed ligand (Cu:R.X= 1:2:2) compounds is established. The interval of obedience to Beer's law equal to 0.12-2.32 mg/mL was determined for Cu-R complexes. For Cu-R-TX-114, Cu-R-DPG and Cu-R-TPG, the determined interval comprised 0.07-2.32 mg/mL. The following values of stability constant for the complexes was established using the spectrophotometric method: 8.75 +/- 0.05 (Cu-R), 9.59 +/- 0.05 (Cu-R-TX-114), 9.85 +/- 0.05 (Cu-R-DPG) and 9.92 +/- 0.04 (Cu-R-TPG). The molar absorption coefficient of the complexes was determined as equal to 10400 (Cu-R), 15000 (Cu-R-TX-114), 15500 (Cu-R-DPG) and 16000 (Cu-R-TPG). The logK(hyd) = 7.5, lgK(hyd) = 12.7 and lgK(hyd) = 13.9 constants of the nickel ion hydrolysis were obtained. The coefficients of the calibration curve equation are determined by the method of least squares. Under optimal complexation conditions, Cu-R was titrated with a component solution (TritonX-114, DPG and TPG) using the conductometric method. The effect of impurity ions and masking substances was studied. The determination of copper (II) is practically unhindered by alkaline, alkaline-earth and some transition elements, such as Ca (II), Ba (II), Mn (II), Cr (III), Sn (IV), Ga (III), In (III) and Zr (IV). The proposed express technique is characterised by its high sensitivity and selectivity, as well as being applicable for the determination of copper in food cereals.

The effect of the third components alpha, alpha'-dipyridyl (alpha, alpha'-dip), ethylene diamine (Ed) and phenontroline (Phen) on the complexation of nickel (II) with 1-phenyl-2-(2-hydroxy-4-nitrophenylhydrozo)butanedione-1,3 was studied. NiR and mixed ligand (NiR alpha,alpha'-dip, NiREd and NiRPhen) complex compounds are formed at pH 6, 5, 4.5 and 5, respectively. The ratio of the reacting components in the composition of homogeneous and mixed ligand complexes was established and the interval of subordination to the Beer's law determined.The developed methodology was applied to specify nickel (II) in the river water.

The new uranyl, nickel and cobalt complexes, [UO2(L1)2(R)] (1), [Ni(L1)2((CH3)2SO)2] (2), [Co(H2O)4(HL2)2]·2H2O (3) and [UO2(H2O)2(HL2)2]·2H2O (4), were prepared by reaction of UO2(CH3COO)2·2H2O, Ni(CH3COO)2·4H2O or Co(CH3COO)2·4H2O with 1,3-diphenyl-propane-1,3-dione (H2L1) or 4-(2-(2,4-dioxopentan-3-ylidene)hydrazinyl)benzoic acid (H2L2) in the presence of N,N-diethylnicotinamide (R) (for 1). Complexes 1–4 were characterized by elemental analysis, IR spectroscopy, ESI-MS and single crystal X-ray diffraction technique. In both 1 and 2 the (L1)− coordinates in a bidentate chelating mode where the UO22+ in 1 exhibits a distorted pentagonal bipyramidal and Ni2+ in 2 a distorted octahedral geometries. In 3 and 4 a hydrazone moiety containing an intramolecular resonance assisted hydrogen bond, with N–H⋯O distances of 2.5469(18) and 2.549(7) Å, respectively, was found in the coordinated ligand (HL2)−. The supramolecular networks (packing diagrams) of 1–4 are constructed via hydrogen bonding, CH–π or π–π interactions. All the four complexes (1–4) act as a good catalyst towards the diastereoselective nitroaldol (Henry) reaction of aliphatic and aromatic aldehydes with nitroethane in different solvents such as acetonitrile, methanol or water. Complex 3 was found to be efficient catalyst for the Henry reaction in aqueous medium, providing β-nitroalcohols with good yields (68–91%) and diastereoselectivities (syn/anti 77:23–73:27).

In the title compound, [Cu(C(12)H(11)N(2)O(4))(2)(C(10)H(14)N(2)O)(2)(H(2)O)(2)], the Cu(II) atom lies on a center of inversion and is coordinated by carboxyl-ate O atoms, pyridine N atoms and two water mol-ecules in an elongated octa-hedral geometry. The pyridine ring is oriented at a dihedral angle of 74.83 (12)° with respect to the benzene ring. Intra-molecular O-H⋯O and N-H⋯O hydrogen bonding is observed. The water mol-ecule is a hydrogen-bond donor to the carbonyl O atom of an adjacent carboxyl-ate group, generating a chain running along the a axis. One of the ethyl groups is disordered over two sets of sites in a 0.787 (5):0.213 ratio.

Single crystal X-ray diffraction is used to determine the crystal and molecular structure of 4-trifluoro-2-[2-(4-fluorophenyl)hydrazine-1-ylidene]-1-(thiophen-2-yl)butane-1,3-dione. Crystallographic data for C 14 H 8 F 4 N 2 O 2 S are as follows: a = 8.2723(6) Å, b = 9.3009(7) Å, c = 9.9895(7) Å; α = 79.224(2)°, β = 75.851(2)°, γ = 72.337(2)°. Triclinic crystal system, P -1 space group, d x = 1.622 g/cm 3 , V = 704.83(9) Å 3 , μ = 0.286 mm −1 , crystal size 0.30×0.20×0.20 mm, R 1 = 0.0891, wR 2 = 0.1989.

In the title compound, [Cu(C12H11N2O4)2(C10H14N2O)2(H2O)2], the CuII atom lies on a center of inversion and is coordinated by carboxylate O atoms, pyridine N atoms and two water molecules in an elongated octahedral geometry. The pyridine ring is oriented at a dihedral angle of 74.83 (12)° with respect to the benzene ring. Intramolecular O—H...O and N—H...O hydrogen bonding is observed. The water molecule is a hydrogen-bond donor to the carbonyl O atom of an adjacent carboxylate group, generating a chain running along the a axis. One of the ethyl groups is disordered over two sets of sites in a 0.787 (5):0.213 ratio.

The Cu-II atom in the title compound, [Cu(C12H11N2O4)(2)(C10H14N2O)(H2O)](n), lies in a square plane defined by the O atoms of the carboxylate ions, the N atom of the N-heterocycle and the water molecule. Coordination by an amido O atom of an adjacent N-heterocycle in the apical direction leads to a polymeric chain running along [011]. The chain motif is consolidated by hydrogen bonds involving the water molecule; the water molecule is a hydrogen-bond donor to the free carbonyl atoms of the carboxylate ions. Intramolecular N-H center dot center dot center dot O hydrogen bonds also occur.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.