Complexation Of Gold Research Articles

Investigation of gold-amino acid interactions using Fourier Transform Infrared spectroscopy and correlation with gold dissolution; Studies at different pH values

Recent developments in the field of gold leaching using amino acids have generated an interest in understanding the bonding/interactions involved in gold amino acid complexation. So far, only Density Function Theory (DFT) models have predicted the bonding of gold with amino acids, and there has been limited experimental work to verify the postulated quantum models. This study therefore aims to address the identification of amino-gold interactions using Fourier Transform Infrared spectroscopy (FTIR) and interrogate the predicted DFT interactions of gold and amino acids. The selected amino acids for this investigation were glycine, alanine, cysteine and histidine. Interactions were investigated at different pH levels corresponding to the isoelectric point and deprotonation points of respective amino acids. In addition to the FTIR investigation, gold dissolution experiments were conducted to establish a possible relationship between the interactions and gold dissolution at the explored pH points. FTIR analysis indicated that gold forms complexes with amino acids through N–Au, O–Au, and S–Au bonds. These bonds were evidenced by observed peak changes in the NH3+, COO−, and S-associated IR vibration peaks during the complexation process. In turn, the IR vibration peaks supported the DFT predictions of the active site for the bonding between gold and amino acids. Notably, the analysis revealed significant vibrational shifts in the characterization peaks of ligands at the deprotonation pH across all four amino acids, signifying a high interaction between gold and amino acids with high pH levels. Moreover, the dissolution of pure gold using the four amino acids at 0.5 M concentration of amino acid, 187 mg/L solid w/v, 1 % H2O2 and 300 rpm agitation indicated that gold dissolution was more favourable at the deprotonation pH compared to the isoelectric ph. Overall, the results showed that high dissolution was observed at deprotonation pH that corresponded to high FTIR peak shifts observed on deprotonated amino acid complexation. Lastly, the study hints at a possible correlation between the nature of gold amino-acid complexation and the extent of gold dissolution, which could require further investigation.

Amplified photomodulation of a bis(dithienylethene)-substituted phosphine.

Phosphine ligands play a crucial role in homogeneous catalysis, allowing fine-tuning of the catalytic activity of various metals by modifying their structure. An ultimate challenge in this field is to reach controlled modulation of catalysis in situ, for which the development of phosphines capable of photoswitching between states with differential electronic properties has been proposed. To magnify this light-induced behavior, in this work we describe a novel phosphine ligand incorporating two dithienylethene photoswitchable moieties tethered to the same phosphorus atom. Double photoisomerization was observed for this ligand, which remains unhindered upon gold(I) complexation. As a result, the preparation of a fully ring-closed phosphine isomer was accomplished, for which amplified variation of phosphorus electron density was verified both experimentally and by computational calculations. Accordingly, the presented molecular design based on multiphotochromic phosphines could open new ways for preparing enhanced photoswitchable catalytic systems.

ON THE INTERACTION OF H[AuCl2] WITH 2-ETHYLIMIDAZOLE INTERACTION OF [AuCl2]- WITH 2-ETHYLIMIDAZOLE AT 278-318K

Using the potentiometric titration method, the process of complexation of gold (I) with 2-ethylimidazole was studied. Adding an organic ligand solution to the [AuCl2]-/Au system leads to a smooth decrease in the electrode potential (without any jumps). The nonlinearity of the dependence of E on –log[2EI] indicates the stepwise nature of complex formation between [AuCl2]- and 2-ethylimidazole. The general stability constants of successively formed complexes were determined in the temperature range 278-318K (at T=298K, logβ1=4.41±0.03; logβ2=10.81±0.02). An increase in temperature leads to the stability of the formed complexes. It has been shown that trivalent gold complexes are superior in stability to similar gold(I) complexes. The thermodynamic functions of the process of complex formation of gold (I) with 2-ethylimidazole were calculated using the temperature coefficient method. The value of enthalpy (∆Н0) was determined by the tangent of the slope of the direct dependence logβί0=f(1/T), the value of entropy (∆S0) by the segment cut off by this straight line on the ordinate axis, while the change in the isobaric-isothermal potential was calculated according to the equation ∆G0 =∆H0-T∆S0. It was revealed that the replacement of chloride ions with the ultraspherical molecule of 2-ethylimidazole is accompanied by a positive change in enthalpy. This experimental fact is associated with the difference in the binding energies of gold-chlorine (Au-Cl) and gold-2-ethylimidazole (Au-2-EI). A positive change in enthalpy makes a negative contribution to the spontaneous occurrence of complexation reactions. At the same time, the value of ∆S0 for the studied system has a positive value. In the [AuCl4]- –2-EI-H2O system, the number of particles participating in the complexation reaction remains unchanged. The positive change in entropy is most likely due to the release of the H2O molecule from the hydration shell of each of the reactants. A positive change in entropy promotes the spontaneous occurrence of complexation reactions in the studied system.

COMPLEX FORMATION OF GOLD (I) WITH 2-METHYLIMIDAZOLE

The complex formation process of Au (I) with 2-methylimidazole was studied by potentiometric titration. When 2-methylimidazole is added to the [AuCl2]-/Au system, the potential gradually decreases without any jumps. The nonlinearity of the dependence of E on –lg[2MI] indicates the stepwise nature of the complex formation between [AuCl2]- and 2-methylimidazole. The general and thermodynamic stability constants of the complexes were determined in the temperature range of 278-318 K (at T=298 K, lgβ0[AuСl(Н2МИ)]+=13.84±0.03; lgβ10[Au2МИCl]=5.38±0.05; lgβ20[Au(2МИ)2]+=10.60±0.03). The reliability of the determination of the constants is proved by the satisfactory agreement between the experimentally found values of the potentials (Eex.) with theoretical ones (Etheor.). As the temperature increases, the stability of the complexes increases. A change in the ionic strength of the solution has little effect on the stability of the complexes. Comparison of the process of complexation of gold (I) and gold (III) with 2-methylimidazole shows that the stability of the complexes of trivalent gold is superior to similar complexes of gold (I). The thermodynamic functions of the complex formation reaction were calculated by the temperature coefficient method. In this case, the value of ΔrН0 was determined from the tangent of the slope of the direct dependence lgβ0=f(1/T), and the value of ΔrS0 was determined from the segment cut off by this straight line on the y-axis. The change in the isobaric-isothermal potential was calculated by the equation ΔrG0= ΔrН0-TΔrS0. The substitution of chloride ions for a 2MI molecule is accompanied by a positive change in ΔН, which has a negative contribution to the spontaneous course of reactions. For the [AuCl2]- - 2MI system, the number of particles participating in the reaction remains unchanged and the positive change in ΔS is most likely due to the release of water molecules from the hydration shell of the initial substances and reaction products.

Complexation of Gold(III) with Pyridoxal 5'-Phosphate-Derived Hydrazones in Aqueous Solution.

Today, complexes of gold(I) and gold(III) are recognized as promising drugs for the treatment of bacterial infectious diseases and oncological diseases, respectively. It is of interest to broaden the area of potential use of gold(III) compounds to the pathogenic microorganism as well. The first step towards the development of new antibacterial drugs based on Au3+ complexes is the study of their stability in an aqueous solution. The present contribution reports on the investigation of gold(III) complexation with five hydrazones derived from a well-known biologically active compound, pyridoxal 5'-phosphate (one of the aldehyde forms of the B6 vitamin). The complex formation in aqueous solutions was confirmed by mass spectrometry and fluorescent spectroscopy. The stoichiometric composition of the complexes formed and their stability constants were determined using a UV-Vis titration method. The complexes are quite stable at physiological values of pH, as the speciation diagrams show. The results of the paper are helpful for further studies of gold(III) complexes interaction with biomacromolecules.

Gold(III) Complexation in the Presence of the Macropolyhedral Hydridoborate Cluster [B20H18]2−

Gold(III) complexation with the octadecahydrido-eicosaborate anion [B20H18]2− was studied for the first time. It was found that when gold(III) complexes [Au(L)Cl2]BF4 (L = bipy, phen) reacted with [B20H18]2−, complexes [Au(L)Cl2]2[B20H18] were isolated. The compounds consisted of a cationic gold(III) complex [Au(L)Cl2]+ and the hydridoborate cluster as a counterion. X-ray diffraction studies revealed weak B–H...Au interactions for both compounds. Note that more reactive anions [BnHn]2− (n = 10, 12) in similar reactions with gold(III) complexes resulted in gold mirror reactions.

Optical resolution of 1,16-dihydroxytetraphenylene by chiral gold(iii) complexation and its applications as chiral ligands in asymmetric catalysis.

We report herein a novel approach involving optical resolution of (±)-1,16-dihydroxytetraphenylene (DHTP) by chiral gold(iii) complexation. This method features several key advantages, i.e., recyclability of chiral resolution reagents, feasibility of scaling up to gram quantities, and operational simplicity. On the basis of this method, which led to optically pure DHTP, a library of 2,15-diaryl (S)-DHTPs and several (S)-DHTP-derived phosphoramidite ligands were synthesized. Finally, the superior performance of a (S)-DHTP phosphoramidite ligand was demonstrated by efficient iridium-catalyzed asymmetric allylic alkynylation reactions.

Iodine adlayer mediated gold electrooxidation in bis(trifluoromethylsulfonyl)amide-based ionic liquids

Conventional complexing ligands for the wet etching of gold are hazardous, making large-scale utilization problematic. In particular, the environmental risks caused by these materials must be minimized. To address this problem, an electrochemical etching method for gold using bis(trifluoromethylsulfonyl)amide ([Tf2N]–)-based ionic liquids (ILs) has been developed. Here, only one layer of conventional complexing ligand, that is, iodine on gold, is required to achieve the continuous dissolution of gold under a positive electrode potential. In addition, the etching behavior involves sacrificial anode electrolysis (SAE) to generate gold nanoparticles (AuNPs). It was found that the electrochemical oxidation of gold is strongly dependent upon the type of halide ion, and the iodine-modified gold electrode produced a large oxidation peak in [Tf2N]–-based ILs. The voltammetric profiles of iodine-modified gold electrodes reveal that the electronic charge consumed during the electrochemical oxidation is affected by the IL cation and the crystallographic orientation of gold, increasing as ammonium < imidazolium < pyrrolidinium and Au(111) < Au(100) < Au(110), respectively. Of the IL anions evaluated in this study, the apparent oxidation peak was only observed for iodine-modified gold electrode in [Tf2N]–-based ILs, suggesting that [Tf2N]– anions promote gold complexation and act as ligands. Further, microscopic and spectroscopic measurements provide evidence of gold dissolution after electrochemical oxidation and the formation of gold complexes, followed by the generation of AuNPs. The results reveal a mechanism for the iodine-catalyzed electrochemical oxidation of gold in [Tf2N]–-based ILs. The electrolysis of gold in the ILs reported here opens avenues for acquiring novel aurate salts with IL anions and AuNPs.

Straightforward synthesis of gold nanoparticles by adding water to an engineered small dendrimer.

A small water-soluble phosphorus-containing dendrimer was engineered for the complexation of gold(I) and for its reduction under mild conditions. Gold nanoparticles were obtained as colloidal suspensions simply and only when the powdered form of this dendrimer was dissolved in water, as shown by transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX) analyses. The dendrimers acted simultaneously as mild reducers and as nanoreactors, favoring the self-assembly of gold atoms and promoting the growth and stabilization of isolated gold nanoparticles. Thus, an unprecedented method for the synthesis of colloidal suspensions of water-soluble gold nanoparticles was proposed in this work.

On the Complexation of Gold(I) with Glutathione in Aqueous Solutions

Some processes of interaction between $${\text{AuCl}}_{2}^{ - }$$ and glutathione with the formation of polymeric $$\left( {-{\text{AuGSH}}_{i}-} \right)_{n}^{n(i - 2) + }$$ and monomeric $${\text{Au}} ({\text{GS}})_2{\text{H}}_{i}^{i - 5}$$ gold(I) complexes in aqueous solutions at ionic strength of I = 0.2 mol·L−1 (NaCl) have been studied at 25 °C. The precipitate formed in the acidic region corresponds to the ordinary polymer $$\left( {-{\text{AuGSH}}_{2}-} \right)_{n}$$. The dependence of its solubility upon pH has been investigated. The substitution equilibria, $${\text{Au}}({\text{GS}})_{2}^{5 - } + {\text{S}}_{2} {\text{O}}_{3}^{2 - } \rightleftharpoons {\text{Au}}({\text{GS}}){\text{S}}_{2} {\text{O}}_{3}^{4 - } + {\text{GS}}^{3 - }$$, log10 β1 = − 4.5 ± 0.3, and $${\text{Au}}({\text{GS}})_{2}^{5 - } + 2{\text{S}}_{2} {\text{O}}_{3}^{2 - } \rightleftharpoons {\text{Au}}({\text{S}}_{2} {\text{O}}_{3} )_{2}^{3 - } + 2{\text{GS}}^{3 - }$$, log10 β2 = − 8.5 ± 0.2, have been studied and the effective protonation constants of the complexes have been determined. It is shown that under the action of $${\text{AuCl}}_{4}^{ - }$$ GSH is oxidized to sulfinic and sulfonic acids. The potential of using highly stable gold(I) complexes with glutathione as ligands, for metal ions having an affinity with respect to the amine nitrogen atom, has been established.

Determination of Trace Amounts of Gold in Electroplating Rinsing Bath by Slotted Quartz Tube Flame Atomic Absorption Spectrometry with Matrix Matching Calibration Strategy after Preconcentration with Vortex Assisted Dispersive Liquid–Liquid Microextraction

With the aim of mitigating the low sensitivity of the conventional flame atomic absorption spectrometer (FAAS) for gold determination, a dispersive liquid–liquid microextraction (DLLME) method was used to preconcentrate gold from the sample solution and a slotted quartz tube (SQT) was attached to the FAAS burner head to boost the residence time of the atoms in the flame. Three main optimization studies were performed to enhance the absorbance signal of gold by the FAAS system. The SQT-FAAS system was optimized based on the fuel and sample flow rates and the position of SQT on the burner head. Parameters including the pH and volume of buffer solution, volume of ligand solution, and mixing period were optimized for the efficient complexation of gold with diethyldithiocarbamate. The DLLME method was optimized based on the type and volume of dispersive and extraction solvents, type of ionic salt and mass of ionic salt. With the optimized values obtained, 1.7 and 5.6 µg/L were determined to be the method limit of detection (LOD) and limit of quantification (LOQ), respectively. The method applicability and accuracy in quantifying gold in a real sample matrix were determined by the use of spike recovery tests of electroplating rinse bath solution. Close to 100% recovery results were obtained using a matrix matching calibration method.

Gold solubility in alkaline and ammonia-rich hydrothermal fluids: Insights from ab initio molecular dynamics simulations

Knowledge of speciation and thermodynamic properties for aqueous gold complexes are important for both the understanding and numerical modelling of the formation of hydrothermal gold deposits. While gold speciation in chlorine- and sulfur-rich hydrothermal fluids has been investigated by considerable theoretical and experimental studies, the complexation of gold with other ligands that may be important for transporting gold in hydrothermal fluids, such as hydroxyl (OH−) and ammonia (NH3) complexes, have received limited attention so far.In this study, we conduct ab initio molecular dynamics (MD) simulations to calculate the coordination structures of Au(I)–OH and Au(I)–NH3 complexes. Our simulations show linear structures of Au(I) complexes with two bonded ligands (OH−/NH3/H2O), consistent with previous experimental and theoretical studies of Au(I) complexation (e.g., Liu et al., 2014). The new speciation models show that Au(I)–OH−/NH3/H2O complexes are stable in hydrothermal fluids and vapors. We also use thermodynamic integration to determine the formation constants of these species at temperatures up to 350 °C and at water-saturated pressures; furthermore, we extrapolate these properties to wider temperatures and pressures range based on the Modified Ryzhenko–Bryzgalin equation of state parameters. In particular, this study, for the first time, reports the speciation and formation constants of mix-ligand [Au(NH3)(OH)]0(aq) complexes. The derived formation constants show that the stability of Au(I)–NH3 complexes decreases progressively with increasing temperature. The quantitative modelling of gold solubility based on the new thermodynamic data shows that gold can be transported as Au(I)–OH−/NH3 complexes in sulfur-poor and ammonia-rich hydrothermal fluids. In sulfur-bearing ore fluids, ammonia is only likely to transport small amounts of gold as [Au(NH3)(OH)]0(aq) in hydrothermal fluids in the near-neutral to alkaline fluids under extremely reduced conditions.

Photochromic Benzo[b]phosphole Alkynylgold(I) Complexes with Mechanochromic Property to Serve as Multistimuli‐Responsive Materials

AbstractA series of novel benzo[b]phosphole alkynylgold(I) complexes has been demonstrated to display photochromic and mechanochromic properties upon applying the respective stimuli of light and mechanical force. Promising multistimuli‐responsive properties of this series of gold(I) complexes have been successfully achieved through judicious molecular design, which involves incorporation of the photochromic dithienylethene‐containing benzo[b]phosphole into the triphenylamine‐containing arylethynyl ligand that is susceptible to mechanical force‐induced color changes via gold(I) complexation. With excellent thermal irreversibility and robust fatigue resistance of this series of gold(I) complexes, multicolor states controlled by the photochromism and mechanochromism have been realized. Repeatable photochromic and mechanochromic cycles without apparent loss of reactivity have also been observed under ambient conditions. The present work provides important insight and an alternative strategy for the molecular design of multistimuli‐responsive materials, paving the way for further development of the underexplored photoresponsive gold(I) complexes and the multistate photocontrolled system.

Photochromic Benzo[b]phosphole Alkynylgold(I) Complexes with Mechanochromic Property to Serve as Multistimuli-Responsive Materials.

A series of novel benzo[b]phosphole alkynylgold(I) complexes has been demonstrated to display photochromic and mechanochromic properties upon applying the respective stimuli of light and mechanical force. Promising multistimuli-responsive properties of this series of gold(I) complexes have been successfully achieved through judicious molecular design, which involves incorporation of the photochromic dithienylethene-containing benzo[b]phosphole into the triphenylamine-containing arylethynyl ligand that is susceptible to mechanical force-induced color changes via gold(I) complexation. With excellent thermal irreversibility and robust fatigue resistance of this series of gold(I) complexes, multicolor states controlled by the photochromism and mechanochromism have been realized. Repeatable photochromic and mechanochromic cycles without apparent loss of reactivity have also been observed under ambient conditions. The present work provides important insight and an alternative strategy for the molecular design of multistimuli-responsive materials, paving the way for further development of the underexplored photoresponsive gold(I) complexes and the multistate photocontrolled system.

Vibrational spectroscopic investigation of the gold complexation within the cascade structure of phosphorus-containing dendrimer

The interaction of the phosphoric dendrimer with gold was performed by means of vibrational spectroscopy and quantum chemistry. Stable complexes are formed with a PN−PS linkage, whereas with an isolated PS bond this does not occur.The change in geometric parameters and delocalization of electric charge under the influence of gold was discovered. The classification of bands in the experimental vibrational spectra of the dendrimer and its complex was carried out.HOMO of molecule of the dendrimer is localized on the SPNP linkage, whereas the LUMO is located on the terminal group. In the SPNP linkage there is a noticeable delocalization of the charge which leads to a change in the reactivity of this group. Interaction energy was estimated as the difference between the energies of the complex and the energies of the molecules of the dendrimer G′0 and two molecules AuCl and is equal to 25.2 eV. The ionization energy IE and electron affinity EA for AuCl are higher than for dendrimer, therefore, when the complex is formed, these quantities increases. Chemical potential and the electrophilicity index in the complex also increases.

Gold and pathfinders metalloorganic forms in podzol soil at the area of Novye Peski gold deposit (South Karelia)

Gold and natural organic matter interaction, including the interaction with humic and fulvic acids, is the most important part in migration and precipitation of that chemical element in supergene zone. Research into elementorganic forms of gold and related elements, which are often associated with gold deposits (As, Cu, Ag, Ni, Zn, Pb, Te, Bi, Se, Mo, Sb), allowed us to learn the groups of elements bounding preferably to one or the other humus acids and the most enriched with that element’s soil horizons. Complexation of gold and nickel are with both humic and fulvic acids; zinc, silver and antimony bound preferably to humic acids, arsenic and copper — with fluvic acids. More detailed research of different mobile forms of gold in soil profiles allowed us to identify the features of gold forms related with the type of soil horizon and location of soil profile in relation to the ore zone.

Additional Aspects of Complexation of Gold(I) with Thiomalate

Some equilibria involving gold(I) thiomalate (mercaptosuccinate, TM) complexes have been studied in the aqueous solution at 25 °C and I = 0.2 mol·L−1 (NaCl). In the acidic region, the oxidation of TM by $$ {\text{AuCl}}_{4}^{ - } $$ proceeds with the formation of sulfinic acid, and gold(III) is reduced to gold(I). The interaction of gold(I) with TM at nTM/nAu ≤ 1 leads to the formation of highly stable cyclic polymeric complexes $$ {\text{Au}}_{m} \left( {\text{TM}} \right)_{m}^{*} $$ with various degrees of protonation depending on pH. In general, the results agree with the tetrameric form of this complex proposed in the literature. At nTM/nAu > 1, the processes of opening the cyclic structure, depolymerization and the formation of $$ {\text{Au}}\left( {\text{TM}} \right)_{2}^{*} $$ occur: $$ {\text{Au}}_{4} ( {\text{TM)}}_{4}^{8 - } + {\text{TM}}^{3 - } \rightleftharpoons {\text{Au}}_{ 4} ( {\text{TM)}}_{5}^{11 - } $$ , log10 K45 = 10.1 ± 0.5; 0.25 $$ {\text{Au}}_{4} ( {\text{TM)}}_{4}^{8 - } + {\text{TM}}^{3 - } \rightleftharpoons {\text{Au(TM)}}_{2}^{5 - } $$ , log10 K12 = 4.9 ± 0.2. The standard potential of $$ {\text{Au(TM)}}_{2}^{5 - } $$ is $$ E_{1/0}^{ \circ } = -0. 2 5 5\pm 0.0 30{\text{ V}} $$ . The numerous protonation processes of complexes at pH < 7 were described with the use of effective functions.

Non-viral Gene Delivery.

Although viral vectors comprise the majority of gene delivery vectors, their various safety, production, and other practical concerns have left a research gap to be addressed. The non-viral vector space encompasses a growing variety of physical and chemical methods capable of gene delivery into the nuclei of target cells. Major physical methods described in this chapter are microinjection, electroporation, and ballistic injection, magnetofection, sonoporation, optical transfection, and localized hyperthermia. Major chemical methods described in this chapter are lipofection, polyfection, gold complexation, and carbon-based methods. Combination approaches to improve transfection efficiency or reduce immunological response have shown great promise in expanding the scope of non-viral gene delivery.

COMPLEXATION OF GOLD (III) WITH 1-FURFURYLIDENE AMINO-1,3,4-TRIAZOLE AT 288 – 318 K

The potentiometric titration method was used to determine the ionization constant of 1-furfurylideneamino-1,3,4-triazole (pKk = 11.83 log.). The dominating region of 1-furfurylideneamino-1,3,4-triazoles (FF) was identified in a wide pH range. It was shown that 1-furfurylideneamino-1,3,4-triazole ion (HL+) predominates in the pH range up to 0.5-2.0. At pH of 5.0 to 10.5, the neutral molecule (L) predominates, and at pH&gt;13.0 1-furfurylideneamino-1,3,4-triazolate ion (L-) predominates in a solution. To determine the number of a particles formed during the interaction of Au (III) with FF from the potentiometric titration data the dependence of ΔE on -lg [FF] was used for 1-furfurylideneamino-1,3,4-triazole gold (III) complexes at 288-318 K. The slope of the curves of the ΔE-lg [FF] with the excess of 1-furfurylideneamino-1,3,4-triazole at temperatures of 288, 298 and 308 K is 0.059, 0.060 and 0.061 V/mol/l-1, which corresponds to the sequential addition of three molecules of 1-furfurylideneamino-1,3,4-triazole to gold (III). At the temperature of 318 K it is not possible to find the slope angle corresponding to the tris complex due to a quick change in the potential with an excess of FF in a solution. General stability constants of 1-furfuryldenoamino-1,3,4-triazole complexes of Au (III) according to potentiometric titration data was determined by the Friedman method and non-linear least squares method. It was shown that as the temperature increases, the general stability constants of gold (III) complexes are reduced. It was shown that the introduction of substituents into the 1,2,4-triazole molecule affects both the number of particles formed in a solution and the stability of the complexes. Thus, in the system Au (III) -1,2,4-triazole-H2O at 298 K four complex particles are formed, and in the Au (III) system, 1-furfurylideneamino-1,3,4-triazole-H2O only three are formed. The general stability constants of 1,2,4-triazole complexes equal to lgβ1 = 6.56, lgβ2 = 11.13, lgβ3 = 14.94 and lg4 = 18.78 log units, and for 1-furfurylideneamino-1,3,4-triazole complexes Igβ1 = 5.92, lgβ2 = 10.14, lgβ3 = 13.80 log units. The thermodynamic functions of complexe formation were calculated by the temperature coefficient method. It was shown that all complex particles are enthalpy-stabilized. The greatest increase in the exothermicity of the reactions is observed when a complex of three organic-ligand molecules is formed. The value of ΔS at all steps of complexation is negative, which is most likely due to the decrease in the number of particles in a system under study. The spontaneous reaction of complexation is determined by the enthalpy factorFor citation:Safarmamadov S.M., Muborakkadamov D.A., Mabatkadamova K.S. Complexation of gold (III) with 1-furfurylidene amino-1,3,4-triazole at 288 – 318 K. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 5. P. 37-43.

Arsole-Containing π-Conjugated Polymer by the Post-Element-Transformation Technique.

A synthetic method to obtain an arsole-containing π-conjugated polymer by the post-transformation of the organotitanium polymer titanacyclopentadiene-2,5-diyl unit with an arsenic-containing building block is described. The UV/Vis absorption maximum and onset of the polymer were observed at 517 nm and 612 nm, respectively. The polymer exhibits orange photoluminescence with an emission maximum (Emax ) of 600 nm and the quantum yield (Φ) of 0.05. The polymer proved to exhibit a quasi-reversible redox behavior in its cyclic voltammetric (CV) analysis. The energy levels of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) were estimated to be -5.43 and -3.24 eV, respectively, from the onsets for oxidation and reduction signals in the CV analysis. Further chemical modification of the arsole unit in the π-conjugated polymer by complexation of gold(I) chloride occurred smoothly resulting in the bathochromic shift of the UV/Vis absorption and lowering of the LUMO energy level.