The synthesis of low-toxic photosensitizers with an optimal ratio of fluorescence and singlet oxygen generation intensity (theranostics) is an urgent task. Dipyrromethene difluoroborates (BODIPYs) occupy a significant place in this area of research. We present the results of the synthesis, structural analysis, study of the chromophore, fluorescent and generation characteristics of BODIPYs, substituted with bromine atoms at the alpha,alpha-, 13,13-and 13 ',13 '- positions of the molecule, their photo-and thermal stability, as well as the features of aggregation behavior in a mixed solvent THF-water. The results obtained were analyzed in comparison with non-halogenated compounds. It has been established that the introduction of bromine atoms into the BODIPY molecule quenches the fluorescent intensity and enhances the singlet oxygen generation. (alpha-Br)2-and (13-Br)2-substituted BODIPYs can be considered as potential theranostics with a predominant bioimaging function, while (13 '-Br)2-BODIPY exhibits a photosensitizer function to a greater extent. Symmetric bromination of BODIPY has a little effect on photo-and thermal stability compared to unsubstituted analogues. The studied bromine substituted boron(III) dipyrromethenates are characterized by the formation of non-fluorescent H-aggregates in a mixed THF-water solvent with a water content in the mixture above 70%.

5,10,15,20-tetrakis(1'-carboxymethylpyrid-4-yl)porphyrin tetrachloride (1) and 5,10,15,20-tetrakis(1'-carboxymethylpyrid-4-yl)porphyrin tetrabromide (2) were synthesized. Water-soluble tetrapyridylporphine derivatives are salts of halides with multicharged cations with a complex aromatic structure. Thermal effects of dissolution of crystalline tetrapyridylporphins (1) and (2) in water and in aqueous solutions of KOH at 298.15 K were determined by direct calorimetric method. The integral enthalpies of dissolution were measured on a variable temperature calorimeter with an isothermal shell that we designed. The reaction part of the calorimeter and all internal parts in contact with the solution are made of titanium alloy VT-1. The volume of the calorimetric cell was similar to 60 cm(3). The stability of the thermostating system during calorimetric measurements was maintained with an accuracy of 10(-3) K. The standard enthalpies of formation of compounds were calculated using the additive group method. This method takes into account the influence of the primary environment for atoms. The values of the standard enthalpy of tetrapyridylporphine formation and its dissociation products in an aqueous solution were obtained for the first time. They are key quantities in the thermochemistry of this compound, open up the possibility of conducting rigorous thermodynamic calculations in systems with tetrapyridylporphine. The differences in thermochemistry of porphyrins (1) and (2) related to different counter -ion (chloride or bromide) opens a possibility to use solution calorimetry for distinguishing between these ions, which can be useful in some industrial applications.

4-[(S)-2-Methyl-3-hydroxypropyloxy]-4'-formylazobenzene, 4-(3-hydroxypropyloxy)-4'-formylazobenzene and µ-oxodimer of iron 2,8,12,18-tetramethyl-3,7,13,17-tetra-n-amylporphine were synthesized using known methods. A mixture with a certain concentration of components was prepared from the synthesized compounds. The resulting mixture was used as an impregnation of the wide-porous adsorbent Chromaton N-AW. The degree of impregnation was 10

Oxovanadium((IV)) etioporphyrin-III, VO-EtioP-III is an important member of the petroporphyrin family. It can be isolated from crude oil or synthesized de novo from the dipyrromethene precursors, the latter being the approach we used in our research. The molecular structure of VO-EtioP-III was for the first time characterized by single-crystal X-ray diffraction. Both terminal alkyls and the axial oxygen atom protrude in the same direction relative to the molecular plane, while rear side of the molecule remains almost flat. This results in a peculiar centrosymmetric packing (space group P2(1)/c, monoclinic system with four molecules per unit cell), in which back-to-back oriented molecules form the parallel-plane dimers. The powder X-ray diffraction data indicate that the VO-EtioP-III films deposited by vacuum evaporation retain a very strong texture, with all molecules standing vertically on the substrate surface. The absorption spectra of films differ from the solution spectra by a large redshift of the Soret- and Q- band (similar to 30 nm) with hypo- and hyperchromic effects, respectively. The former band strongly broadens due to multiple splitting to within 350-520 nm, which is followed by a change of the color from purple (in diluted solutions) to brawn (in films or crystals).

The study focuses on the development of a method of synthesis of a photosensitive mixture of controlled composition containing cationic water-soluble 5,10,15,20-tetrakis( N -Me-pyridin-3-yl)chlorin and 5,10,15,20-tetrakis( N -Me-pyridin-3-yl)bacteriochlorin. The diimide reduction of 5,10,15,20-tetrakis(pyridin-3-yl)porphine in pyridine and in the absence of a solvent has been studied. It has been shown that the reduction in the melt significantly decreases the reaction duration (from 12 to 1.5 h) and affords compositions in up to 90% yield.

In this review, we generalize the research results obtained by Russian scientists in the last 10-15 years for porphyrins, related compounds, and their metal complexes with a pronounced application potential. The main attention is paid to the analysis of relationships between the spectral, catalytic, and sensor properties of tetrapyrrole compounds and the structure of peripheral substituents and axial ligands and the nature of the coordinating metal atom.

The sorption of vapors from the gas phase of a number of compounds on the surface of a wide-pore adsorbent Chromaton N-AW modified with a mixture of 4-(2-hydroxyethoxy)-4′-formylazobenzene–µ‑oxodimer 2,8,12,18-tetramethyl-3,7,13,17-tetra- n -amylporphine has been studied by the method of inverted gas chromatography. Electrodonor isomers of methylpyridines and dimethylpyridines, isomers of weakly polar xylenes, and a number of enantiomers have been selected as sorbates. The specific retention volumes of sorbates have been calculated, enthalpy and entropy contributions to the sorption process has been shown, and the analytical properties of the resulting stationary phase have been studied. The effect of temperature and the chemical nature of sorbates on the thermodynamic characteristics of sorption has been discussed. The separation factors of both structural and optical isomers and low-boiling hydrocarbons of various structures have been calculated. The influence of both components of the mixture on the sorption process has been considered: the formation of supramolecular ensembles with specific interactions and possible complex formation with iron µ-oxodimer 2,8,12,18-tetramethyl-3,7,13,17-tetra- n -amylporphine. It has been experimentally established that the sorbent based on the proposed mixture of mesogenic 4-(2-hydroxyethoxy)-4′-formylazobenzene and the iron µ-oxodimer 2,8,12,18-tetramethyl-3,7,13,17-tetra- n -amylporphine exhibits high selectivity with respect to low-boiling compounds of various nature, which is unattainable for an unmodified adsorbent. It has been concluded that the use of the presented modifiers in gas chromatography makes it possible to study new stationary phases based on similar mixtures using macrocycles of various structures and nature, promising from the point of view of both structural and chiral gas chromatography.

В данном обзоре обобщены результаты исследований в области порфиринов, родственных соединений и их металлокомплексов с явно выраженным прикладным потенциалом, выполненных российскими учеными в последние 10-15 лет. Основное внимание сосредоточено на анализе взаимосвязи спектральных, каталитических и сенсорных свойств тетрапиррольных соединений со строением экваториального порфиринового и аксиальных лигандов и природой координирующего атома металла.

The π-conjugation pathways were identified and the degrees of aromaticity for NH-tautomers of corrole free bases were determined by quantum chemistry methods and absorption spectroscopy. The macrocycle skeletal atoms participated differently in the formation of the π-conjugation pathway. It was supposed that conjugation pathways consisting of 18 π-electrons were dominant. At the same time, each of two NH-tautomers possessed its own distinct π-conjugation pathway, which caused their degrees of aromaticity to differ. It was shown that the peripheral substitution architecture of the macrocycle influenced the degree of aromaticity. A method for controlling the equilibrium between the two NH-tautomers that consisted of designing the electron-density distribution in the macrocycle that was characteristic of one of the tautomers was proposed and proved experimentally.

The structure of a free nickel (II) octamethylporphyrin (NiOMP) molecule was determined for the first time through a combined gas-phase electron diffraction (GED) and mass spectrometry (MS) experiment, as well as through quantum chemical (QC) calculations. Density functional theory (DFT) calculations do not provide an unambiguous answer about the planarity or non-planar distortion of the NiOMP skeleton. The GED refinement in such cases is non-trivial. Several approaches to the inverse problem solution were used. The obtained results allow us to argue that the ruffling effect is manifested in the NiOMP molecule. The minimal critical distance between the central atom of the metal and nitrogen atoms of the coordination cavity that provokes ruffling distortion in metal porphyrins is about 1.96 Å.

The multistage purposeful synthesis of 5,15-bis(4′-l-N-tyrosinylamidophenyl)-10,20-bis(N-methylpyridin-3′-yl)porphine diiodide was carried out, and the optimum synthesis conditions were determined. 5,15-Bis(4′-nitrophenyl)-10,20-bis(pyridin-3′-yl)porphine served as the starting porphyrin. The structure, individual character, and purity of the target compound were proved by electron spectroscopy, 1H NMR spectroscopy, mass spectrometry (MALDI TOF), and TLC. Specific features of the interaction of the synthesized porphyrin with S-protein of SARS-CoV-2 were studied using spectral and thermochemical methods, including conditions of photoirradiation. The photoirradiation of the synthesized porphyrin in a complex with the SARS-CoV-2 S-protein can result in the partial oxidation of amino acid residues of the protein and distort its primary and secondary structures. The photoirradiation of the S-protein complex with the porphyrin decreases its thermal resistance to melting by 15 °C compared to the free S-protein and causes porphyrin release.

The dipyrromethene derivatives as new chromo-fluorogenic chemosensors for quantitative detection and express analysis of Zn2+ ions were synthesized and structural characterized. The sensing process of dipyrromethene toward Zn2+ was evaluated by UV–vis and fluorescence spectroscopy, molar ratios plots, and DFT calculations. The complexation of Zn(AcO)2 with dipyrromethenes in DMF solution was accompanied by significant bathochromic and hyperchromic effects in the electronic absorption spectra due to the formation of [ZnL2] complex. The 1:2 (Zn:HL) binding mode was proposed on the basis of absorption and theoretical studies. The complexation constants (lgKo) of Zn(AcO)2 with dipyrromethenes are from 8.1 to 10.9, which implying the potential of dipyrromethenes to acts as selective chemosensors for Zn2+. It is shown for the first time that the hexamethyl-substituted dipyrromethene could recognize Zn2+ ions in DMF solution through significant (almost 100 times) "off–on" fluorescent response caused by Zn2+ and visible color change from yellow to bright green under UV irradiation induced by formation of [ZnL2]. Hexamethyl-substituted dipyrromethene had high selectivity towards Zn2+ ions over many environmentally relevant ions, and high sensitivity with the detection limit in nanomolar level (4·10–8 mol/L). In terms of the thermodynamic constant and the fluorescence response of the complexation reaction of [ZnL2], as well as the detection limit of Zn2+ ions, dipyrromethene HL2 surpasses many Zn2+ sensors known in the literature. Dipyrromethenes can be a tool for detecting Zn2+ ions with simple test strips.

The nickel octasubstituted tetraporphyrinate (Ni-S(+)TPP) was studied as a dopant of nematic mixtures based on alkoxycyanobiphenyls (CB-6) and Schiff bases (SB-2). An analysis of the textures allowed to establish the formation of chiral nematic phases, to measure their clearance temperatures, the degree of dopants influence on the LC, and helical pitch. High helical twisting power was calculated (126.5 mu m-1 for CB-6 and 63.5 mu m-1 for SB-2). Anomalous temperature dependences of the LC dielectric permittivity were obtained, due to competition between the chiral dopant, which twisted the mesophase, and the magnetic field, which untwisted LC helix. On the base of quantum chemical calculations, the formation of stable solvates of Ni-S(+)TPP with 1 and 2 alkoxycyanobiphenyl molecules due to axial coordination and inclusion was established. Solvates involving Schiff bases are less stable due to the impossibility of axial coordination. These conclusions were confirmed by(1)H NMR and ROESY.

Synthesis of 5-phenyl-2,3,7,8,12,18-hexamethyl-13,17-diethylporphyrin and its dinitro derivatives, containing nitro groups in positions 10, 20 of the porphyrin nucleus, was performed. Structure of the obtained compounds was proved by NMR, IR, mass spectroscopy, and EAS spectra. The kinetics of formation reactions of zinc, copper, and cobalt complexes of the synthesized porphyrins in pyridine and acetic acid was investigated. Connection of the porphyrin ligands reactivity with electronic effects of nitro groups, effects of the spatial distortions of the porphyrin nucleus, and the structure of solvation shells of 3d-metal salts is discussed.

This work provides the results of the spectroscopic, electrochemical, and photoelectrochemical study of the self-assembly in the systems consisting of (2,3,7,8,12,13,17,18-octaethylporphinato)cobalt(II) (CoOEP), (2,3,7,8,12,18-hexamethyl,13,17-diethyl,5-(4-pyridyl)porphinato)gold(III) chloride (ClAuP)/1'-N-methyl-2'-(pyridin-4-yl)pyrrolidino[3',4':1,2][60]fullerene (PyC60), and 1,2-dichlorobenzene/toluene as an electron donor, an acceptor, and a liquid medium, respectively. The results indicate axial coordination of electron acceptor functionalized by the pyridine units by cobalt(II) porphyrin with the donor-acceptor (ClAuP)(2)CoOEP/(PyC60) 2CoOEP triad formation. The thermodynamic stability constant is (4.91 +/- 1.10)x10(9) L-2 mol(-2) and (4.10 +/- 1.14) x10(10) L-2 mol(-2) for ClAuP and PyC60, respectively. The formation of supramolecules was confirmed by UV, visible, IR, H-1 NMR spectroscopy and cyclic voltammetry. DFT calculations (B3LYP+def2-SVP) detect octahedral geometry of the coordination center with the trans configuration of the axial ligands in the triads as well as the excited state calculations establish photoinduced electron transfer (PET). The j(ph)(avg) value 266 mu A cm(-2) for the Ti vertical bar(ClAuP)(2)CoOEP vertical bar 0.5 M Na2SO4 vertical bar Pt system being 2-2.5 times higher compared with the precursors and slightly higher compared with (PyC60)(2)CoOEP shows that gold(III) porphyrin as an electron acceptor can be successfully used. The development of donor/acceptor platform selection strategy for the obtaining of photoactive supramolecules is an urgent task for future deriving of photovoltaic devices. (C) 2021 Elsevier B.V. All rights reserved.

Tetrakis{5,6-bis(4- tert -butylphenyl)pyrazino[2,3- c ]}porphyrazine and tetra(4- tert -butyl)phthalocyanine have been synthesized, and their acid–base properties and electronic absorption and fluorescence spectra in acetonitrile and toluene at 298 and 295 K, respectively, have been studied. The synthesized compounds have been identified by electronic absorption and 1 H NMR spectroscopy and mass spectrometry. The effect of substituents in the molecular fragments of the macrocycle on the electronic and optical properties of the synthesized compounds has been estimated.

Absorption and magnetic circular dichroism (MCD) spectra have been measured and theoretically simulated for a series of palladium octaethylporphyrins substituted at the meso positions with phenyl groups (n = 0-4). Analysis of the spectra included the perimeter model and time-dependent density functional theory (TDDFT) calculations. With the increasing number of phenyl substituents, the molecule is transformed from a positive hard (ΔHOMO > ΔLUMO) to a soft (ΔHOMO ≈ ΔLUMO) chromophore. This is manifested by a drastic decrease of the absorption intensity in the 0-0 region of the Q-band and by the strongly altered ratio of MCD intensities in the Q and Soret regions. Such behavior can be readily predicted using perimeter model, by analyzing frontier orbital shifts caused by various perturbations: alkyl and aryl substitution, insertion of a metal, and deviations from planarity. TDDFT calculations confirm the trends predicted by the perimeter model, but they fail in cases of less symmetrical derivatives to properly reproduce the MCD spectra in the Soret region. Our results confirm the power of the perimeter model in predicting absorption and MCD spectra of large organic molecules, porphyrins in particular. We also postulate, contrary to previous works, that the isolated porphyrin dianion is not a soft chromophore, but rather a strongly positive-hard one.

The molecular structures and spectral and luminescent properties of 2,3,7,13,17,18-hexamethyl-8,12-di-nbutylcorrole and 7,13-dimethyl-8,12-di-n-butylcorrole free bases in solutions at 288–328 K were studied using luminescence and absorption spectroscopy and quantum chemistry. Absorption and fluorescence spectra of the compounds were shown to be superimposed spectra of two NH-tautomers. Individual tautomer spectra were identified. Bands were assigned to specific transitions. NH-tautomer equilibria in the ground S0 and lower excited S1 singlet states were characterized.

The synthesis of 5,15-diphenyl-3,7,13,17-tetramethyl-2,8,12,18-tetraethylporphyrin and its nitro substituted was carried out. Nitro groups are located in meso-positions of the tetrapyrrole macrocycle and (or) para-positions of the phenyl rings. The synthesized porphyrins are characterized by a set of modern research methods: electron absorption spectroscopy; IR and nuclear magnetic resonance spectroscopy 1H. The reactions of the formation of manganese complexes with nitro-substituted 5,15-diphenyl-3,7,13,17-tetramethyl-2,8,12,18-tetraethylporphyrin and their stability in organic solvents are studied. It was found that the rate of reactions of formation of manganese complexes in pyridine with the introduction of nitrogroups in 5,15-diphenyl-3,7,13,17-tetramethyl-2,8,12,18-tetraethylporphine grows as the degree of deformation of the tetrapyrrole macrocycle increases. Obviously, in this case, not only the stretching of NH bonds, due to the presence of electron-withdrawing substituents (NO2) in the para positions of the phenyl rings, makes a decisive contribution to the energy of the transition state, but also the increase in the basicity of tertiary nitrogen atoms, which form strong bonds in the transition state with a solvated cation of salt. In acetic acid, the macrocycle deformation effect leads to a decrease in the reaction rate, which is due to the specific solvation of the porphine reaction center by acetic acid molecules. It was found that steric distortions of the planar structure of porphyrins have relatively little effect on the kinetic parameters of the solvoprotolytic dissociation of manganese complexes of 5,15-diphenyl-3,7,13,17-tetramethyl-2,8,12,18-tetraethylporphyrin and its nitro-substituted ones. This is probably due to the fact that the coordination of the manganese cation results in a more planar structure of the porphyrin macrocycle. The decrease in the dissociation reaction rate with an increase in the number of nitrogroups in 5,15-diphenyl-3,7,13,17-tetramethyl-2,8,12,18-tetraethylporphyrine is due to the influence of the negative inductive effect of nitrogroups, which reduces the effective charge in the macrocycle on nitrogen atoms that are attacked by a solvated proton.