Chloroform Solution Research Articles

Prevalence of Epstein-barr Virus (EBV) among Patients with Oral Squamous Cell Carcinoma from Ahvaz, Iran: A Case-Control Study

Epstein-Barr virus (EBV), one of the most significant causes of lymphoid and epithelial cancers, has been linked to oral carcinogenesis; however, this etiological association remains controversial. To investigate this association, the present study aimed to determine the prevalence of EBV in cancerous and non-cancerous oral tissues from Ahvaz, Iran. In total, 164 blocks of formalin-fixed paraffin-embedded tissues from oral squamous cell carcinoma (OSCC), including 76 tongue squamous cell carcinomas and 88 non-cancerous tongue tissues, were collected from Ahvaz Imam Khomeini Hospital, Ahvaz, Iran, from December 2014 to March 2019, for this case-control study. The tissues were cut into 15-μm-thick sections, and DNA was extracted using a solution of Phenol, Chloroform, and Isoamyl Alcohol. The EBV detection and typing were performed using nested polymerase chain reaction. The EBV was detected in 9 (5.48%) out of the 164 samples studied, including 4 (5.26%) of the 76 SCC cases and 5 (5.68%) of the 88 samples in the control group (P>0.05). The EBV was positive in 2.40% of the 83 male and 8.6% of the 81 female samples (P>0.05). In terms of the histological grades of the case group, 3 (3/57) and 1 (1/13) of the EBV-positive samples were well and moderately differentiated, respectively (P>0.05). For EBV typing, the 9 EBV-positive samples were tested, and it was found that 2 and 7 of the cases were EBV type I and II, respectively. Results of the current study demonstrated the low frequency of EBV in Iranian patients with OSCC, with EBV type II predominating. Further studies are required to clarify the association between EBV and OSCC.

Dual Photoredox and Copper Catalysis: Enantioselective 1,2-Amidocyanation of 1,3-Dienes

Dual photoredox–transition-metal catalysis has emerged as a powerful tool for the development of chemical transformations. However, its application in the selective difunctionalization of 1,3-dienes remains essentially unexploited. By the synergistic action of photoredox and copper catalysts, we report herein an enantioselective 1,2-amidocyanation of 1,3-dienes. Visible-light irradiation of a chloroform solution of conjugated dienes, N-Boc-amidopyridinium salts, and TMSCN in the presence of a catalytic amount of fac-Ir(ppy)3, Cu(OTf)2·xH2O, and a chiral Box ligand affords three-component adducts in good to high yields with high regio- and enantioselectivities. A L*CuCN complex, fully characterized spectroscopically and confirmed by X-ray crystallographic analysis, is able to catalyze the transformation, therefore supporting an inner-sphere cyanide transfer pathway.

Probing the Electron Transfer Behavior from Excited State Organometal Lead Halide Perovskite Nanocrystals to Molybdenum Disulfide Nanoflowers

The charge transfer study from the excited state of MAPbBr3 perovskite nanocrystals (PNCs) to molybdenum disulfide (MoS2) in chloroform solution is conducted using a fluorescence approach. Due to their exceptional properties and distinctive structures, transition metal dichalcogenides (TMDs) are promising candidates for optoelectronic devices. In this study, we have combined hybrid organic–inorganic perovskite nanocrystals MAPbBr3 with MoS2 solution. A significant electron transfer from MAPbBr3 to MoS2 has been depicted by photoluminescence (PL) spectroscopy, time-correlated single-photon count (TCSPC), transient absorption spectroscopy (TAS), and shortening of the absolute PL quantum yield (PLQY) of hybrid MAPbBr3/MoS2 nanocomposites. Fluorescence quenching of perovskite nanocrystals has shown an increase in quenching efficiency. The photoexcited charge transfer from MAPbBr3 to adjacent MoS2 is further correlated using electrochemical tests that compare reduction and oxidation potential. The results revealed that MoS2 extracts the charge from the excited state of PNCs. This work demonstrates the charge transfer properties of hybrid halide perovskites with two-dimensional TMD materials. A combination of these materials could help us to understand the actual potency of MAPbBr3 PNCs in their real applications.

Distribution of Cd (II) Between Buffered Aqueous Solutions and Chloroform Solution of 4,4´-(1e,1e´)-1,1´-(ethane-1,2-diylbis(azan-1-yl-1ylidene)bis(5-methyl-2-phenyl-2,3-dihydro-1h-pyrazol-3-ol) (H2BuEtP)

The distribution of Cd(ll) between buffered aqueous solutions and chloroform solution of 4,4´-(1e,1e´)-1,1´-(ethane-1,2-diylbis(azan-1-yl-1ylidene)bis(5-methyl-2-phenyl-2,3-dihydro-1h-pyrazol-3-ol) (H2BuEtP) and the effect of 1-(3-hydroxy-5-methyl-2-phenyl-2,3-dihydro-1h-pyrazol-4-yl) butan-1-one (HBuP) as a synergist in the distribution was studied. The concentration of Cd (ll) in aqueous phase after shaking was determined with an Atomic Absorption Spectrophotometer at wavelength of 228nm and the distribution determined by difference. pH 4. 75 - 7.5 was the range in which > 90% distribution of cadmium into organic phases occurred. Slope analysis was used to predict the probable extraction reactions and also the distributing cadmium complexes as Cd(HBuEtP)X and Cd(HBuEtP.BuP) respectively. HBuP slightly increased the pH1/2 from 3.87 ± 0.18 to 4.88 ± 0.12 and partition coefficient KD from 2.19 ± 0.35 to 3.15 ± 0.42. However, the extraction constant Kex2Cd ((-10.09 ± 0.09) in the presence of HBuP was < Kex1Cd (-3.01± 0.9) for H2BuEtP alone. It was recommended that kinetics studies and effect of acids, anions and auxiliary complexing agents on the distribution of cadmium be investigated to fully evaluate the potentials of H2BuEtP in the extraction of cadmium from aqueous media.

Nonlinear Optical Responses of Photoswitchable Donor–Acceptor Stenhouse Adducts

This work combines hyper-Rayleigh scattering (HRS) experiments performed in the NIR range (1.30 and 1.60 μm) and quantum chemical calculations to provide a comprehensive description of the second harmonic generation (SHG) responses of donor-acceptor Stenhouse adducts (DASAs). Representative derivatives of the three generations of DASAs, which differ by the nature of their electron-donating and withdrawing moieties and also include clickable species, have been synthesized and their photoswitching behavior fully characterized. The HRS measurements allow us to establish relationships between the magnitude of the SHG response of open forms and the nature of the donor and acceptor groups. The largest SHG responses are obtained for derivatives incorporating either a barbituric acid or an indanedione acceptor unit, while N-methylaniline appears as the most efficient donor group. The calculations support well the experimental data and show that high hyperpolarizabilities are associated to low excitation energies and large extent of the photoinduced intramolecular charge transfer, which enhances the dipole moment variation between the ground and first dipole-allowed electronic excited state. In addition, a complete investigation of the photoswitching kinetics of DASAs in chloroform solution shows important differences, highlighting in particular the role of the donor group on the photoswitching efficiency.

Effect of Chain Structure on the Various Properties of the Copolymers of Fluorinated Norbornenes with Cyclooctene.

Fluorinated polymers are attractive due to their special thermal, surface, gas separation, and other properties. In this study, new diblock, multiblock, and random copolymers of cyclooctene with two fluorinated norbornenes, 5-perfluorobutyl-2-norbornene and N-pentafluorophenyl-exo-endo-norbornene-5,6-dicarboximide, are synthesized by ring-opening metathesis copolymerization and macromolecular cross-metathesis in the presence of the first- to third-generation Grubbs' Ru-catalysts. Their thermal, surface, bulk, and solution characteristics are investigated and compared using differential scanning calorimetry, water contact angle measurements, gas permeation, and light scattering, respectively. It is demonstrated that they are correlated with the chain structure of the copolymers. The properties of multiblock copolymers are generally closer to those of diblock copolymers than of random ones, which can be explained by the presence of long blocks capable of self-organization. In particular, diblock and multiblock fluorine-imide-containing copolymers show a tendency to form micelles in chloroform solutions well below the overlap concentration. The results obtained may be of interest to a wide range of researchers involved in the design of functional copolymers.

High-Performance Pseudo-Bilayer Organic Solar Cells Enabled by Sequential Deposition of D18/Y6 Chloroform Solution

Recently, sequential deposition (SD) fabricated pseudo-bilayer organic solar cells (OSCs) have achieved preferable performances compared to the long-term adopted bulk heterojunction (BHJ)-based devices, in which the solution-processing technique is the key to preparing the active layer of electron–donor materials and electron–acceptor materials. For devices with D18 as the electron–donor material and Y-serial small molecules as the electron–acceptor materials, however, one single solvent was seldom applied to prepare the corresponding high-performance SD OSCs. In this work, we adopted chloroform as the single solvent and successfully constructed high-performance SD OSCs based on D18 and Y6. Benefiting from the finely adjusting of the vertical phase distribution, the SD low molecular weight D18/Y6 pseudo-bilayer device realized high short-circuit current density (27.24 mA cm–2) and a champion efficiency of 17.94%, which surpassed the 17.36% value of the D18:Y16 device having a bulk heterojunction structure and the 7.81% result of the SD prepared Y6/D18-based device. This work demonstrates a single solvent strategy for fulfilling high-performance SD OSCs and reveals the reasons that account for the distinct performances of these OSCs fabricated by different approaches.

Does a Machine-Learned Potential Perform Better Than an Optimally Tuned Traditional Force Field? A Case Study on Fluorohydrins

We present a comparative study that evaluates the performance of a machine learning potential (ANI-2x), a conventional force field (GAFF), and an optimally tuned GAFF-like force field in the modeling of a set of 10 γ-fluorohydrins that exhibit a complex interplay between intra- and intermolecular interactions in determining conformer stability. To benchmark the performance of each molecular model, we evaluated their energetic, geometric, and sampling accuracies relative to quantum-mechanical data. This benchmark involved conformational analysis both in the gas phase and chloroform solution. We also assessed the performance of the aforementioned molecular models in estimating nuclear spin-spin coupling constants by comparing their predictions to experimental data available in chloroform. The results and discussion presented in this study demonstrate that ANI-2x tends to predict stronger-than-expected hydrogen bonding and overstabilize global minima and shows problems related to inadequate description of dispersion interactions. Furthermore, while ANI-2x is a viable model for modeling in the gas phase, conventional force fields still play an important role, especially for condensed-phase simulations. Overall, this study highlights the strengths and weaknesses of each model, providing guidelines for the use and future development of force fields and machine learning potentials.

Chloroform-infiltrated photonic crystal fiber with high-temperature sensitivity.

The temperature sensor is the core part of the temperature measurement instrument, and its performance directly determines the temperature measurement accuracy. Photonic crystal fiber (PCF) is a new type of temperature sensor with extremely high potential. In this paper, we propose a high-performance, structurally simple, liquid-filled PCF temperature sensor, which is based on a SMF-PCF-SMF (single mode fiber, SMF) sandwich structure. By adjusting the structural parameters of the the PCF, it is possible to obtain optical properties that are superior to those of ordinary optical fibers. This allows for more obvious responsive changes of the fiber transmission mode under small external temperature changes. By optimizing the basic structure parameters, a new PCF structure with a central air hole is designed, and its temperature sensitivity is -0.04696 nm/°C. When filling the air holes of PCFs with temperature-sensitive liquid materials, the response of the optical field against the temperature fluctuations can be effectively enhanced. The Chloroform solution is used to selectively infiltrate the resulting PCF owing to its large thermo-optical coefficient. After comparing various filling schemes, the calculation results show that the highest temperature sensitivity of -15.8 nm/°C is finally realized. The designed PCF sensor has a simple structure, high-temperature sensitivity, and good linearity showing great application potential.

Porous polymer film formation by water droplet templating using polystyrene.

Studies show that the formation of breath figures over polystyrene is not clearly understood-sometimes the patterns are regular and sometimes they are barely formed. In an attempt to understand this process a little more, breath figures over polystyrene of three molecular weights and on the smooth and grooved DVD surfaces are prepared and studied. The microporous films are prepared by the evaporation of the chloroform solution of the polymers in a humid environment. The thus formed breath figure patterns are studied under a confocal laser scanning microscope and the images are analyzed. Breath figures were formed for (a) three molecular weights of the polymer (b) two casting techniques, and (c) on smooth and grooved surfaces (of a commercial DVD). The wetting of the breath figures formed by water is also reported here. The pore diameters were found to increase with increase in molecular weight and also with concentration of the polymer used. Only drop-casting method yield breath figures. Voronoi entropy, calculated from the images, indicates ordered pores on the grooved surface compared to smooth surfaces. Contact angle studies indicate a hydrophobic nature of the polymer, with the hydrophobicity increasing by the patterning.

Ultra-low current electrospray ionization of chloroform solution for the analysis of perfluorinated sulfonic acids.

Femtoamp and picoamp electrospray ionization (ESI) characteristics of a nonpolar solvent were explored. The direct ESI mass spectrometry analysis of chloroform extract solution enabled rapid analysis of perfluorinated sulfonic acid analytes in drinking water. Neat chloroform solvent and extracts were directly used in a typical wire-in ESI setup using micrometer emitter tips. Ionization currents were measured with femtoamp sensitivity while ramping the spray voltage from 0 to -5000 V. Methanol was used as a comparison to illustrate thecharacteristics of electrospraying chloroform. The effects of spray voltage and inlet temperature were studied. A liquid-liquid extraction workflow was developed to analyze perfluorooctanoate sulfonate (PFOS) in drinking water using an ion-trap mass spectrometer. The ionization onset of chloroform solution was 41 ± 17 fA at 300 V. The ionization current gradually increased with voltage while remaining below 100 pA when using voltages up to -5000 V. The ion signal of PFOS was significantly enhanced to improve the limit of detection (LoD) to 25 ppt in chloroform. Coupled with a liquid-liquid extraction workflow, LoD of 0.38-5.1ppt and a quantitation range of 5-400 ppt were achieved for perfluorinated sulfonic compounds in 1-ml water samples. Femtoamp and picoamp modes expand the solvent compatibility range of ESI and can enable quantitative analysis in parts per trillion (ppt) concentrations.

Effect of solvation-dehydration of quaternary ammonium base salts in the organic phase on the selectivity of anion-exchange extraction

ABSTRACT The analysis of the influence of dehydration and solvation (by proton-donor reagents) of halide anions in the organic phase on the processes of their solvent extraction separation with salts of quaternary ammonium bases has been carried out. The possibility of a significant increase in the separation factors of anions in the F-Cl-Br-I series due to endothermic dehydration of amine salts (Aliquat 336) in systems with “weak” proton-donor reagents, such as chloroform has been shown. In particular, the separation factors of the Cl/F pair increase by almost 15 times when going from Aliquat 336 solutions in toluene to extractant solutions in chloroform, for the Br/Cl pair, this increase is up to 5 times, and for I/Cl, about 3 times. In similar systems with additions of alcohols and phenols to the extractant (exothermic dehydration), there is a significant deterioration in the separation parameters of halides. The conclusions are confirmed by the data of 1H NMR studies, which also made it possible to establish some details of the processes of dehydration of amine salts in the studied systems.

PHYSICOCHEMICAL PROPERTIES AND COMPOSITION OF LIPID COMPONENT FROM WINTER GARLIC BULBS (ALLIUM SATIVUM L.)

The lipid composition, presence of the biologically active substances and ability of lipids to the spontaneous aggregation in the water medium of the winter garlic (Allium sativum L.) was studied by TLC, UV-spectrometry with the Gauss mathematic analysis of spectra and dynamic light scattering methods It is shown that share of the more easily oxidizable fractions in the garlic phospholipids is 2.45 times greater than that for the more poorly oxidizable fractions. Mathematic analysis of the UV-spectra of the lipids solution in chloroform revealed the presence of compounds with a conjugated couple bonds and ketodienes and confirmed the literature data about absence of flavonoids. The hydrophilic biologically active compounds are found in a polar phase during extraction of lipids. Analysis of UV-spectrum of 20-hydroxyekdizone in chloroform which is detected in the garlic lipids was done. It was determined the substantial maximum absorption band shift of sterols in UV-spectra of the garlic lipids testifies to their participation with sphigolipids in the raft formation that is due to form of particles with the average diameters 160 nm and the low absolute value of ξ-potential from the garlic lipids in the water medium.

Solvatochromism, Acidochromism and Photochromism of the 2,6-Bis(4-hydroxybenzylidene) Cyclohexanone Derivative.

In this paper, we studied the photophysical behavior of 2,6-bis(4-hydroxybenzylidene) cyclohexanone (BZCH) under the influence of various stimuli. The photophysical properties were correlated with different solvent parameters, such as the Kamlet-Abraham-Taft (KAT), Catalán, and Laurence solvent scales, suggesting that the behavior of BZCH is influenced by both nonspecific and specific solvent-solute interactions. The Catalán solvent dipolarity/polarizability parameters were found to have a significant role in the solvatochromic behavior, which is also confirmed by the KAT and Laurence models. The acidochromism and photochromism properties of this sample in dimethylsulfoxide and chloroform solutions were also investigated. The compound showed reversible acidochromism after the addition of dilute NaOH/HCl solutions, accompanied by a change in color and the appearance of a new absorption band (514 nm). The photochemical behavior was also examined by irradiating BZCH solutions with both 254 and 365 nm light.

Critical Role of Non-Halogenated Solvent Additives in Eco-Friendly and Efficient All-Polymer Solar Cells.

Organic solar cells (OSCs) demonstrating high power conversion efficiencies have been mostly fabricated using halogenated solvents, which are highly toxic and harmful to humans and the environment. Recently, non-halogenated solvents have emerged as a potential alternative. However, there has been limited success in attaining an optimal morphology when non-halogenated solvents (typically o-xylene (XY)) were used. To address this issue, we studied the dependence of the photovoltaic properties of all-polymer solar cells (APSCs) on various high-boiling-point non-halogenated additives. We synthesized PTB7-Th and PNDI2HD-T polymers that are soluble in XY and fabricated PTB7-Th:PNDI2HD-T-based APSCs using XY with five additives: 1,2,4-trimethylbenzene (TMB), indane (IN), tetralin (TN), diphenyl ether (DPE), and dibenzyl ether (DBE). The photovoltaic performance was determined in the following order: XY + IN < XY + TMB < XY + DBE ≤ XY only < XY + DPE < XY + TN. Interestingly, all APSCs processed with an XY solvent system had better photovoltaic properties than APSCs processed with chloroform solution containing 1,8-diiodooctane (CF + DIO). The key reasons for these differences were unraveled using transient photovoltage and two-dimensional grazing incidence X-ray diffraction experiments. The charge lifetimes of APSCs based on XY + TN and XY + DPE were the longest, and their long lifetime was strongly associated with the polymer blend film morphology; the polymer domain sizes were in the nanoscale range, and the blend film surfaces were smoother, as the PTB7-Th polymer domains assumed an untangled, evenly distributed, and internetworked morphology. Our results demonstrate that the use of an additive with an optimal boiling point facilitates the development of polymer blends with a favorable morphology and can contribute to the widespread use of eco-friendly APSCs.

Difluoroborate-based bichromophores: Symmetry relaxation and two-photon absorption

Given potential applications of multiphoton absorbers, in the present work we have studied the symmetry-relaxation effects in one- and two-photon absorption spectra in two bichromophore systems based on difluoroborate core linked by biphenylene or bianthracene moieties. We have employed a palette of experimental methods (synthesis, one- and two-photon spectroscopy, X-ray crystallography) and state-of-the-art computational methods to shed light on how symmetry relaxation, a result of twisting of building blocks, affects one- and two-photon absorption of the two studied fluorescent dyes. Electronic-structure calculations revealed that the planarity of central biphenyl moiety, as well as deviations from planarity up to 30–40 deg., ensure maximum values of two-photon transition strengths. Perpendicular arrangement of phenylene units in biphenylene moiety leads to 20% drop in the two-photon transition strengths. More detailed studies demonstrated that equilibrium structures of both compounds in chloroform solution show very different values of two-photon absorption cross sections at absorption band maxima, i.e. 224 GM for and 134 GM for biphenyle and bianthracene linkers, respectively. The latter value is in good agreement with experimental value obtained using Z-scan method. The difference in two-photon absorption cross section between both compounds can be rationalized based on equilibrium geometry differences, i.e. interplanar angle is 35 deg and 91 deg in the case of biphenylene and bianthracene moiety, respectively. It is thus not beneficial to introduce conformationally locked central linker based on bianthracene moiety.

High‐Efficiency Binary Organic Solar Cells Enabled by Pseudo‐Bilayer Configuration in Dilute Solution

Forming proper film morphology in organic solar cells (OSCs) is important to govern the exciton dissociation and charge transport. Herein, high‐performance pseudo‐bilayer heterojunction (PBHJ) OSCs with donor:acceptor (D:A) bilayer architecture are reported by sequentially depositing two layers of diluted active solution with different D:A ratios. Such pseudo‐bilayer films can not only enable the cascaded components distributed in the vertical direction, but also afford large donor and acceptor (D/A) interfaces for efficient exciton dissociation. Additionally, the D:A active layer on the bottom substrate can act as a seed to promote the crystallization process of the upper film during the sequential casting process. The PBHJ strategy on two representative D:A blends, PM6:Y6 and PTQ10:Y6, is implemented. Benefiting from the synergetic effects of efficient exciton dissociation and balanced charge transport, the devices based on PM6:Y6 and PTQ10:Y6 show high power conversion efficiencies of 17.73% and 17.81%, respectively. Notably, the presented PBHJ devices are fabricated by using dilute chloroform solution (4 mg mL−1 for donor), demonstrating the excellent potential for poorly soluble donors and acceptors in future OSCs applications.

Reusable, Ultrasensitive, Patterned Conjugated Polyelectrolyte-Surfactant Complex Film with a Wide Detection Range for Copper Ion Detection.

Conjugated polyelectrolytes (CPEs) are emerging as promising materials in the sensor field because they enable high-sensitivity detection of various substances in aqueous media. However, most CPE-based sensors have serious problems in real-world application because the sensor system is operated only when the CPE is dissolved in aqueous media. Here, the fabrication and performance of a water-swellable (WS) CPE-based sensor driven in the solid state are demonstrated. The WS CPE films are prepared by immersing a water-soluble CPE film in cationic surfactants of different alkyl chain lengths in a chloroform solution. The prepared film exhibits rapid, limited water swellability despite the absence of chemical crosslinking. The water swellability of the film enables the highly sensitive and selective detection of Cu2+ in water. The fluorescence quenching constant and the detection limit of the film are 7.24 × 106 L mol-1 and 4.38 nM (0.278 ppb), respectively. Moreover, the film is reusable via a facile treatment. Furthermore, various fluorescent patterns introduced by different surfactants are successfully fabricated by a simple stamping method. By integrating the patterns, Cu2+ detection in a wide concentration range (nM-mM) can be achieved.

Synthesis and Self-Assembly of β-Octa[(4-Diethoxyphosphoryl)phenyl]porphyrins.

The β-substituted porphyrinoids commonly used to form functional assembled systems in nature yet are still scarcely used in material chemistry probably due to the laborious synthesis of these compounds. In this work, β-octa[(4-diethoxyphosphoryl)phenyl]porphyrin (2HOPPP) and its metal (Zn(II), Cd(II), Cu(II), and Ni(II)) complexes were prepared in good yields. These highly soluble chromophores were characterized in solution using spectroscopic (NMR, UV-vis, fluorescence), electrochemical, and spectroelectrochemical methods. Attachment of the electron-deficient residue (ArP(O)(OEt)2) to the porphyrin macrocycle leads to easier reductions and harder oxidations of the macrocycle for all complexes studied as compared to corresponding meso-tetra[4-(diethoxyphosphoryl)phenyl]porphyrin derivatives reported previously. We demonstrated that the strong electron-deficient character of the MOPPP porphyrins results principally from the increase in the number of electron-withdrawing groups at the periphery of the tetrapyrrolic macrocycle. Electron-deficient porphyrins are highly required in supramolecular and material chemistry in part due to their ability to form supramolecular assemblies via the coordination of axial ligands to the central metal atom. According to single-crystal X-ray data, ZnOPPP forms in the crystalline phase dimers in which each of the two tetrapyrrolic macrocycles is connected through an unusual combination of hydrogen bonding of two phosphoryl groups and the water molecules axially coordinated to the zinc atom of the partner molecule. The involvement of water molecules in porphyrin binding allows for an increase of distance between two porphyrin mean N4 planes, up to 4.478 Å. The offset of phosphoryl groups attached to the macrocycle through a 1,4-phenylene spacer withdraws the whole porphyrin macrocycle of one molecule from spatial overlap with the macrocycle of a partner molecule and increases the Zn-Zn distance up to 10.372 Å. This still unknown type of porphyrin dimers allows one to get deeper insights into the organization of naturally occurring tetrapyrrolic macrocycles. ZnOPPP also forms a labile dimeric complex in 5.3 × 10-7-5.8 × 10-5 M chloroform solutions. In contrast, other complexes prepared in this work exist as monomeric species under these experimental conditions. The self-association constant of ZnOPPP has been determined by electronic absorption spectroscopy.

Photoisomerization of 1,2-Di(4-pyridyl)ethylene According to NMR and UV Spectroscopy Data and Density Functional Modeling.

Photoisomerization of 1,2-di(4-pyridyl)ethylene under UV irradiation was studied by NMR and UV spectroscopy in solutions of acetone, acetonitrile and chloroform. It has been established that in the studied solutions under irradiation, geometric photoisomerization occurs: the trans-isomer transforms into the cis-isomer and then cyclization occurs. DFT modeling of the listed processes, states and UV absorption spectra of the sample in an acetonitrile solution was performed.