The work presents the synthesis procedure and results of the study of the interconnection between the geometric structure of dithia-substituted analogues of tetraphenylporphyrins and their acid-base and spectral properties. Double-protonated forms of bromine-substituted dithiaporphyrins were found to be able to coordinate perchlorate ions in a neutral solvent, which can be of use in designing a receptor platform of liquid-phase sensor materials.

The effect of amino acid fragments on the spectral and complexing (with Zn2+ and Si2+) properties of asymmetrically substituted derivatives of 5,10,15,20-tetraphenylporphyrin: 5-(4'-amino-phenyl)-10,15,20-triphenylporphine, 5-(4'-tyrosinyl-amidophenyl)-10,15,20-triphenylporphine, 5-(4'- N-tretbutoxicarbonylthyrosinyl-amidophenyl)-10,15,20-triphenylporphine, 5-(4'-glycinacylamino-phenyl)-10,15,20-triphenyl-porphine, 5-(4'-N-tretbutoxy-carbonylglycine-aminophenyl)-10,15,20-triphenylporphine in acetic acid at 291-308K was studied. The kinetic parameters of the reactions of the formation of their zinc and copper complexes were determined. The effect of the chemical functionalization of the tetraphenylporphyrin molecule due to the addition of one or more biomolecules to the periphery of the macrocycle on the change in the spectral and coordination properties of the synthesized macromolecule is considered. It is shown that when identifying the patterns of "structure-activity", the most effective method for studying functionalized ligands is the spectrophotometric method, with which it is possible to qualitatively and quantitatively characterize the processes of acid-base equilibrium, complexation, and the influence of the nature of the solvent. It is shown that the change in the rate constants of the zinc acetate and copper acetate coordination reactions of the studied ligands depends on their stability in the reaction medium. It was found that in acetic acid, the tendency of the peripheral substituent to influence the complexing ability of ligands in relation to copper and zinc remained almost the same for all studied ligands. The interrelation of ligand complexation constants with electronic substitution effects, in particular with the total value of the Gammet constant of peripheral substituents, including both resonant and inductive components, the ratio of which depended on the molecular structure of peripheral substituents, is considered. It is shown that the complexation constants of the ligands studied formed a correlation with the total inductive Gammet constant sigma I of the substituent in the para-position of the phenyl ring, and the electronic effect of the substituent was determined mainly by inductive interactions.

Modification of porphyrins by a replacement of N atom(s) with a heteroatom(s), resulted in so called heteroporphyrins, exhibits interesting physicochemical properties. In this work, the spectral properties of ions and neutral forms of 5,10,15,20-tetraphenyl-21,23-dithia porphyrin (S2PP) and 5,10,15,20-tetraphenyl-21-thia-porphyrin (HSPP) have been investigated. According to spectrophotometric analysis in acetonitrile – perchloric acid solution, the dication H2S2PP2+ reveals an ability to coordinate two ClO4- anions, which not happens for H3SPP2+. This fact observed in UV–Vis absorption spectra indicates the possibility of exhibiting chemosensory properties of S2PP molecules. Geometries of the neutral and ionized forms were derived from B3LYP/cc-pVTZ calculations. Perimeters of the cavities increase in the series: H2PP–HSPP–S2PP. This trend is kept for the ionized forms; protonation expands the cavity perimeter. Electron density distributions were analyzed in terms of quantum theory atoms in molecule (QTAIM). The UV-vis spectra simulated by TDDFT fits with the experimental results.

Using theoretical conclusions from the Gouterman four-orbital model, a detailed analysis of the formation of absorption and fluorescence spectra of free bases and their zinc complexes has been performed for 5,10,15,20-tetraphenyl-21-oxaporphyrin and 5,10,15,20-tetraphenyl-21,22-dioxaporphyrin. The influence of the symmetry of the molecule on the position and shape of the bands in the electronic absorption and fluorescence spectra is shown. The kinetic parameters of the reactions of complexation of oxasubstituted derivatives of 5,10,15,20-tetraphenylporphine with d-metal salts (Cu(II), Zn(II), and Co(II)) at 288–308 K have been determined for the first time. The kinetic data obtained for oxasubstituted derivatives have been compared with results obtained for their classical analogue, tetraphenylporphine.

The directed synthesis of asymmetrically substituted porphyrins—tetraphenylporphyrine derivatives containing amino acid residues as a functional group, which can be used as “anchor” groups, for incorporation into the structure of a protein molecule, was carried out. The obtained compounds were characterized by a number of spectral methods confirming their structure and purity. Their base and acid ionization constants in the AN–HClO4 and DMSO–potassium cryptate (KOH[222])—systems were measured by spectrophotometric titration. It was found that the asymmetric substitution architecture contributed to the stabilization of the protonated forms of porphyrins. This allowed, for the first time, to extract and spectrally characterize the mono- and doubly-protonated forms (H3P+ and H4P2+) of each ligands in the AN–HClO4 system. The analysis of the spectral changes of the monoamino derivative led to identify three stages of the protonation, which first involves the nitrogen atom of the periphery substituent (pKb = 13.26) and then the central nitrogen atoms of the macrocycle (pKb1 = 11.50; pKb2 = 9.65; pKb1,2 = 21.15). The relative stability of the first intermediate is assumed to be caused by charge delocalization. The electron-donor nature of the solvent in the DMSO–KOH [222] system led to the leveling of the ionization constants for the first and second stages, which allowed us to determine only the total values for the porphyrins studied. The successive stages of acid–base interactions were analyzed in the article.

Asymmetrically substituted 5,10,15,20-tetraphenylporphyrin derivatives such as5-(4-aminophenyl)10,15,20-triphenylporphine,5-[4-(tyrosinylamino)phenyl]-10,15,20-triphenylporphine and 5-{4-[(N-tert-butoxycarbonyltyrosinyl)amino]phenyl}-10,15,20-triphenylporphinewere synthesized. Their spectral and acid-base properties were studied. Theacid-base interactions of the obtained compounds in the binaryacetonitrile–perchloric acid and dimethyl sulfoxide–potassium cryptate(KOH[222]) systems were studied by spectrophotometry method. The effect of thenature of the solvent, concentration, pH value on the chemical activity ofporphyrin was analyzed. Amino acid fragments affect the protolytic equilibriumof porphyrins in acidic and basic media.

The spectral-luminescent properties of the 21-thia-5,10,15,20-tetraphenylporphyrin and 21,23-dithia-5,10,15,20-tetraphenylporphyrin were studied in solutions at 293 K. The origin of the spectral shifts upon heterosubstitution was discussed on the basis of the Gouterman four-orbital model. It was shown that the quenching of the fluorescence of heteroporphyrins is due to the effect of the internal heavy atom, the role of which plays heteroatom of the thiophene ring.

The work reports first studied kinetics of complexation between copper and heterosubstituted porphyrins, namely 5,10,15,20-tetraphenyl-21-thiaporphyrin and 5,10,15,20-tetraphenyl-21-oxaporphyrin, as well as comparison with the structural analogue being tetraphenylporphyrin. Spectrophotometric titration allowed for determination of basicity constants characterizing heterosubstituted porphyrins in acetonitrile–perchloric acid. An increasing basicity in the porphyrin series: HSP < H2TPP < HOP for about four orders of magnitude is shown as expected to be accompanied with enhancing coordination ability of the ligands.

The acid-base properties of 5,10,15,20-tetraphenyl-21-oxaporphyrin and 5,10,15,20-tetraphenyl-21,23-dioxaporphyrin have been studied by means of spectrophotometric titration. The parameters of electronic absorption spectra and the concentration ranges of the existence of the obtained forms have been determined. Kinetics of the formation of complexes of 5,10,15,20-tetraphenylporphine oxa derivatives with copper at 288–308 K has been studied.

The spectral and luminescent properties of 21-thia- and 21,23-dithia-5,10,15,20-tetraphenylporphyrin were studied in solutions at 293 K. The origin of the spectral shifts of the absorption bands upon heterosubstitution was discussed based on the Gouterman four-orbital model. Fluorescence quenching of the heteroporphyrins was shown to be due to an internal heavy-atom effect of the thiophene-ring heteroatom.

Kinetics of the formation reactions of palladium complexes of meso -nitro-substituted 5-phenyl-β- octaalkylporphine derivatives in the Pd(OAc) 2 –acetonitrile system at 303–323 K was studied by spectrophotometry. The kinetic parameters of the formation reaction of complexes of porphyrins under study with palladium and zinc previously prepared, as well as their corresponding fluorescence spectra, were subjected to a comparative analysis. The parameters of electron absorption spectra of all palladium porphyrinates obtained were determined.

Basic and coordination properties of 5,10,15,20-tetrakis(3,5-dibromophenyl)porphine and 5,10,15,20-tetrakis(4-methoxy-3-bromophenyl)porphine in acetonitrile have been investigated by means of spectrophotometry. The optimization of the geometry parameters of polysubstituted porphyrins has been performed using quantum-chemical method (РМ3). The relationship between geometric structure of the studied porphyrins and their coordination, basic, and spectral properties is discussed.

In the present work the reactions of basic interaction of 5,10,15,20-tetra(4-OH-phenyl) porphyrin in acetonitrile with the perchloric acid are studied by the method of spectrophotometric titration. And the chemical kinetics of ligand with zinc acetate in the dimethylformamide was carried out. The constant of the basic dissociation of the protonated acids of 5,10,15,20-tetra(4-OH-phenyl) porphyrin and kinetic parameters of the reaction of the formation of the zinc complex was obtained. The comparative analysis of our own obtained data and literature data according to the basic and coordination properties of 5,10,15,20-tetra(4-OH-phenyl) porphyrin and 5,10,15,20-tetrapheny porphyrin in acetonitrile and dimetilforamide in the range of 298-333K was carried out, which made it possible to draw a number of the interesting conclusions, which are concerned with the stabilization of the ionic forms of ligand in the acetonitrile and the dimethylformamide and the influence of solvent on the depth of the protonation of ligand and the kinetic rate of the formation of the corresponding zinc complexes. It is shown that the stabilization of the ionic forms of ligand upon transfer from the acetonitrile to dimethylformamide reduces the depth of the protonation of ligand, which is reflected in the decrease of the values of the dissociation constants of the cation forms of porphyrin, and the kinetic rate and the corresponding power expenditures for the reaction of the formation of ZnT(4-OH-Ph)P. It is shown that reactivity of ligand in the dipolar proton-free medium can be regulated by a change in the properties of this medium, which makes it possible to forecast the processes of the synthesis of compounds with the assigned properties.Forcitation:Plotnikova A.O., Ivanova Yu.B., Mamardashvili N.Zh. Investigation of coordination properties of 5,10,15,20-tetra(4-OH-phenyl) porphyrin in acetonitrile and dimethylformamide. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 6. P. 65-71.

10,15-Dinitro-5-phenyl-2,3,7,8,12,13,17,18-octamethylporphine, 10,15,20-trinitro-5-phenyl-2,3,7,8,12,13,17,18-octamethylporphine, and 10,15,20-trinitro-5-(4-nitrophenyl)-2,3,7,8,12,13,17,18-octamethylporphine were synthesized and identified by electronic absorption, IR, and 1 Н NMR spectroscopy. The acid–base properties of the synthesized compounds were studied by spectrophotometric titration in HClO 4 –acetonitrile and 1,8-diazabicyclo[5.4.0]undec-7-ene–acetonitrile systems at 298 K. Parameters of the electronic absorption spectra and concentration ranges of existence of the mono- and diprotonated, as well as mono- and dideprotonated forms of the corresponding ligands and the acid and base dissociation constants of the latter were determined. Comparative analysis of the effect of nitro groups on the reactivity of the synthesized compounds was performed.