The coordination of 1-methyl-2-(pyridin-4'-yl)-3,4-fullero[60]pyrrolidine (PyC60) and 2,5-di-(pyridin-4'-yl)-3,4-fullero[60]pyrrolidine (Py2C60) by zinc phthalocyanines functionalized with carbazole and tert-butyl substituents was studied in this work. The thermodynamics of the transformation and the structure of the reaction product molecules were revealed by the molar ratio method and the methods of UV-vis, IR, 1H NMR spectroscopy, and mass spectrometry, respectively. Thermodynamic stability constants and key spectral characteristics were obtained for the reaction products, which in all cases correspond to a 1 : 1 donor-acceptor complex. The resulting complexes, like all previously described analogs, are characterized by a stability constant whose value fluctuates within one to one and a half orders of magnitude around 105 L/mol, which is 3 to 5 orders of magnitude higher than that for the reaction of metallophthalocyanines with unsubstituted pyridine. These results expand the design possibilities of functional materials for optoelectronics based on fullero[60]pyrrolidines and zinc phthalocyanine complexes.

The self-assembly of the (5,15-bis(4,6-dichloropyrimidin-5-yl)-10,20-bis(2,4,6-trimethylphenyl)porphinato)zinc (II) (ZnPCl4) donor and the (fullero[60]/[70]pyrrolidine)/fullerenol ((PyC60, Py2C70)/C60(OH)n) acceptor were studied in toluene solutions by spectroscopic techniques. The structure of the resulting donor-acceptor dyads was established using the data of MALDI-TOF mass spectrometry, UV-vis, IR and 1H NMR spectroscopy. The stability constant values observed using the spectrophotometric titration method were about 104-105 M-1. The bonding strengths, the geometries and some electronic properties of the dyads were revealed using density functional theory (DFT) calculations. Density functional theory (DFT) calculations implemented to study the bonding strength, geometries and some electronic properties of the dyads showed that ZnPCl4 forms stable complexes with fullerenes, where the bonding energies span from-203 to-136 kJ/mol. The quantum yield values of singlet oxygen for ZnPCl4 and its dyads with fullerenes in toluene or DMSO were determined using the characteristics of singlet oxygen luminescence at 1275 nm. The initial data on the antibacterial activity of the compounds synthesized against Staphylococcus aureus under both the UV irradiation and incubation in the dark confirm the prospects for their further study and use as antimicrobial agents.

The results of a study of the photophysical properties of biligand iron(iii) complexes [FeL12]PF6 and [FeL22]PF6 with carbazole periphery of different degree of branching in various solvents including toluene, 1,4-dioxane, tetrahydrofuran (THF), ethyl acetate, dichloromethane (DCM), and N,N-dimethylformamide (DMF) are presented. Experimental data were obtained by UV—Vis spectroscopy, as well as by steady-state and time-resolved fluorescence spectroscopies. It was established that both [FeL12]PF6 and [FeL22]PF6 exhibit positive solvatochromic behavior. The Stokes shifts increase with solvent polarity to more than 120 nm in DCM and DMF. The degree of branching significantly influences the absolute fluorescence quantum yields, which were higher for [FeL22]PF6. Both compounds demonstrated the ability to generate singlet oxygen (1O2).

Manganese(iii) porphyrin complexes form covalent and coordination pairs with electron acceptors, which are of interest for the fabrication of solar cells due to the photoinduced electron transfer property. In order to determine the nature of the photoexcitation processes in the donor part of these pairs, in this work the excited electronic states of manganese(iii) complexes with 5,10,15,20-tetraphenylporphyrin ((AcO)MnTPP), 5,10,15,20-tetra(4-methylphenyl)porphyrin ((AcO)MnTTP), and 5,10,15,20-tetra(4-tert-butylphenyl)porphyrin ((AcO)MnTBPP) are studied by femtosecond photoinduced absorption spectroscopy. The parameters of the differential absorption spectra of the complexes in toluene, methanol, and tetrahydrofuran are determined, and their interpretation is given. The lifetimes of the excited state, depending on the nature of the substituent in the macrocycle and the solvent, are determined by modeling the kinetics of photo-induced absorption. A dependence of the lifetime of the excited state of manganese(iii) porphyrins on the polarity and the coordination ability of the solvent, as well as a weak dependence on the nature of the porphyrin macrocycle, are demonstrated.

Donor-acceptor systems containing metalloporphyrin as an electron-donor component exhibit the property of photoinduced electron transfer (PET), which makes them promising in obtaining materials for optoelectronics. In a search for new perspective systems with PET we have performed experimental studies of interactions between the newly synthesized (5,15-bis(4,6-dichloropyrimidin-5-yl)-10,20-bis(2,4,6-trimethylphenyl)porphinato)cobalt(II) (CoPCl4) and 1-methyl-2-(pyridin-4'-yl)-3,4-fullero[60]pyrrolidine (PyC60) in toluene at 298 K. The process parameters were obtained, and a complete kinetic description is presented. The process occurs stepwise as reversible and irreversible reactions and ends with the formation of the donor-acceptor triad (PyC60)2CoPCl4 via the formation of an intermediate product—the dyad (PyC60)CoPCl4. The composition and structure of the triad are substantiated using UV-visible, IR, and 1H NMR spectroscopy and MALDI-TOF mass spectrometry data. A comparative analysis was performed of the quantitative parameters of the (PyC60)2CoPCl4 formation reaction with those for structural analogs previously described in the literature; the formation constants of the triads were correlated with their structure, which is important for fine tuning of the properties of functional materials based on them.

Zinc(II) phthalocyanines containing eight tert-butylphenoxy and tert-butylcarbazole groups at the molecule periphery (ZnPc((BuPhO)-Bu-t)(8) and ZnPc(Carb)(8), respectively) were obtained with about 20 % yield by the DBU activated phthalonitrile tetramerization in pentanol and dry quinoline, respectively. Their structure was confirmed using MALDI-TOF mass spectrometry, IR, H-1/C-13 NMR, and electronic absorption/fluorescence spectroscopy. The ZnPc((BuPhO)-Bu-t)(8)/ZnPc(Carb)(8)/H2Pc((BuPhO)-Bu-t)(8) photophysical parameters, including the Q-band wavelength, fluorescence/singlet oxygen quantum yields, fluorescence lifetime, and radiative/non-radiative transition constant in organic solvents, were established. The presence of ZnPc((BuPhO)-Bu-t)(8) and ZnPc(Carb)(8) long-life excited states is confirmed by the fs-TA data. The peripheral carbazole substitution decreases slightly both the fluorescence quantum yield and fluorescence lifetime (by similar to 0.6 ns) relative to that for ZnPc((BuPhO)-Bu-t)(8), but simultaneously increases the possibility of singlet oxygen generation. The formation of the H2Pc((BuPhO)-Bu-t)(8) proton transfer complex in dimethylformamide leading to the increase in singlet oxygen yield more than 3 times was established. Attractive photophysical parameters, non-aggregated state in solutions, and the bathochromically located Q absorption band allow us to consider ZnPc(Carb)(8) as a promising photosensitizer.

A series of novel fluorescence carbazole-functionalized building blocks with increased π-conjugated systems have been synthesized and investigated as potential candidates for carrying out complex formation reactions with metal salts. The combination of data obtained from elemental analysis, IR and NMR spectroscopy, mass-spectrometry and GPC allows us to confirm the suggested linear and bulky dendron's structures. The chemical modification of dendrons with functional groups affects the thermal stability phase behavior and fluorescent properties. Dendrons showed the positive solvatochromism effect, which was confirmed by the red shift when the polarity of the solvents was increased. The fluorescence lifetime for dendrons of the first and second generation decreases with decreasing solvent polarity. The study of the spectral properties of compounds in the solid state showed that the synthesized molecules exhibit bluish-white fluorescence.

In this work a series of mesogens derived from 4-(4-octyloxybenzoyloxy)benzoic acid were synthesized and characterized. They acted as the main reagents in the Claisen condensation reaction to obtain a heterofunctional β-diketone containing both mesogenic long alkyloxybenzoic fragment and carbazole derivatives as chromophore unit in its structure. The results of the study of phase behavior showed that the synthesized elongated derivatives, including 4-(4-octyloxybenzoyloxy)benzoic acid as a key precursor for further modification, exhibit an enantiotropic mesomorphism, SmA and nematic mesophases, whereas the target β-diketone shows SmA mesophase only upon cooling from the isotropic melt. In addition, β-diketone demonstrates bright emission in the solvents of different polarity and in the solid state. The fluorescence quantum yield reaches values from 14 to 64 % depending on the nature of the solvent.

New complexes of [5,10,15,20-tetra-(4-methoxyphenyl)porphinato](chloro)indium(III) ((Cl)InTPP( p -OCH 3 ) 4 ) with unsubstituted C 60 and 1-methyl-2-(pyridin-4'-yl)-3,4- fullero[60]pyrrolidine (PyC 60 ) were synthesized in toluene. The stability constants of 1 : 1 complexes (dyads) were determined using UV-vis and fluorescence spectroscopy. The dyads were characterized by IR and 1 H NMR spectroscopy data. It was established that fluorescence of (Cl)InTPP( p -OCH 3 ) 4 is quenched upon gradual addition of fullerenes. The numerical values of the Stern–Volmer quenching constants ( K SV ) were determined. The most important charge transfer characteristics of dyads (the lifetime of charge-separated states and charge separation and recombination constants), needed for further consideration of dyads based on indium(III) porphyrins as photoinduced electron transfer systems, were determined using femtosecond laser spectroscopy.

To reveal the effect of coordinated organic and inorganic sigma pi-ligands on the magnetocaloric properties of metal ions at room temperature, we have synthesized paramagnetic (5,10,15,20-tetraphenylporphinato)cobalt(II), (chloro)(2,3,7,8,12,13,17,18-octaethylporphinato))manganese(III), their coordination complexes with 1-methyl-2-(pyridin-4 '-yl)-3,4-fullero[60]pyrrolidine (1:3 and 1:2, respectively), and (ethoxy)(oxo)(5,10,15,20-tetraphe-nylporphinato)molybdenum(V) and have fully characterized their chemical structure by UV-vis, IR, 1H NMR, MALDI TOF spectral methods. Using the direct microcalorimetric method and DSC we have obtained, respec-tively, magnetocaloric effect, heat, change of enthalpy/entropy during the magnetization over the temperature range of 285 - 338 K in magnetic fields from zero to 1 T and the specific heat capacities in the temperature range from 270 to 400 K in zero fields for paramagnets synthesized. Involving the results of DFT calculations, we have shown that the electron structure of a central metal atom is the determining factor in the positive magnetocaloric effect in the complexes studied. The decrease in the MCE value is observed in the case of the intramolecular antiferromagnetic interactions in external magnetic fields (manganese(III) complexes) and additional axial bonding of the bulk fullerene-containing base.

A new dendrimeric cobalt(II) complex CoP has been obtained when reacting (5,15-bis[3,5-bis( tert -butyl)phenyl]-10,20-bis{4,6-bis[3,5-bis(3,6-di- tert -butylcarbazole-9-yl)phenoxy]pyrimidin-5-yl}porphine with Co(AcO) 2 ·4H 2 O. The process of two-step two-way coordination of 1-methyl-2-(pyridin-4'-yl)-3,4-fullero[60]pyrrolidine (PyC 60 ) with cobalt(II) porphyrin ends with the formation of a stable 1 : 2 complex, a triad of composition (PyC 60 ) 2 CoP. The process has been completely kinetically described using UV-vis and fluorescent spectroscopy data. The stability constant ( K ) of the coordination complex is (9.9 ± 2.4) × 10 8 L 2 mol –2 (log K = 9.0). The chemical structure of the triad has been determined by UV-vis, 1 H NMR, and IR spectroscopy. The effect of PyC 60 fluorescence quenching in the triad has been found and studied, and the static mechanism of the quenching process has been substantiated. The result can be used in optoelectronics to optimize the structures of donor–acceptor systems with the property of photoinduced electron transfer.

UV-vis, IR, MALDI-TOF, and femtosecond transient absorption spectroscopic techniques together with DFT and TDDFT computations have been employed to explore new manganese(III) porphyrins bearing [3,6-di-tert-butyl- carbazol-9-yl-benzoyloxy]- (MnP1) and [3,6-bis(3",6"-di(tert-butyl)-9"H-carbazol)-9H-carbazolbenzoyloxy] phenyl (MnP2) groups. MnP1 and MnP2 demonstrate the significant deviation of the macrocycle from planarity, which can be due to the high spin (S = 2) state of the manganese(III). By studying MnP1 and MnP2 excited states, the formation of the trip-quintet ones decaying in 13.7 ps and 17.3 ps, respectively, was established. The comparisons of MnP1 and MnP2 with the Co and Zn analogs have shown that both the number of generations and metal ion influence excited-state dynamics and electronic/structural properties.

We make a brief overview of the results of studies into the reactivity of iridium and rhenium complexes in various oxidation states with substituted, expanded, N-fused, and N-confused porphyrins, corroles, as well as heteroatomic macrocycles under chemical and electrochemical oxidation conditions. The characteristic spectral features of the species are analyzed, as well as the key factors responsible for the stabilization of the charge of the complexing ion and the charge location during the oxidation of compounds on the aromatic part of the molecule, the central metal atom, or the axial ligand. Iridium and rhenium in the oxidation state of +1 to +7 form stable complexes with porphyrins and their analogues, which are of particular interest due to their unusual properties and a potential for use in various fields of science and technology, including advanced materials and catalysts. The high reactivity in redox processes with a reaction center on the macrocycle or on the central ion is the main feature of iridium and rhenium porphyrin complexes. The high stability not only of molecular species, but also of charged radical species of complexes is of great interest for further progress in the study of the mechanisms of their chemical and photophysical transformations, understanding of which is necessary for the development of applied chemistry of porphyrin complexes of iridium, rhenium, and their analogues.

Results of studying the ultrafast dynamics of excited states of cobalt(II) and manganese(III) octakis(3,5-di-tert-butylphenoxy)phthalocyanines, along with donor–acceptor systems based on them with fullero[60]- and fullero[70]pyrrolidines as acceptors are represented. Excited states are achieved by exposing the absorbing substances to laser pulses in femtosecond absorption spectroscopy. The kinetics and types of photoinduced absorption spectra of metal phthalocyanines and their dyads with substituted pyrrolidines are described, along with the lifetimes of states with separated charges. The corresponding constants of charge separation and recombination are determined.

Studying the axial chemistry of metalloporphyrins enables the transition to supramolecular structures, including nanoscale ones, for sensorics and optoelectronics. Taking into account the high axial reactivity and high coordination numbers of molybdenum(V) in its porphyrin complexes, we have studied the reactions of oxo[5,10,15,20-tetra(4-methylphenyl)porphinato](ethoxy)molybdenum(V) with 4-picoline and N -methyl-2-(pyridin-4-yl)-3,4-fullero[60]pyrrolidine in toluene by chemical thermodynamics and kinetics methods, UV-visible and IR absorption spectroscopy, 1 H NMR, fluorescence, and mass spectrometry. The chemical structure of intermediates and products of complex reactions (coordination triads of composition molybdenum(V) porphyrin : fullero[60]pyrrolidine = 1 : 2) and their key spectral parameters have been established. By determining the electron-optical parameters of the triads and precursors, the prospect of using molybdenum(V) porphyrin as an optical chemosensor of highly volatile and other nitrogenous bases has been substantiated. The observed effect of fluorescence quenching of molybdenum(V) porphyrin as part of a triad can be useful in the development of photosensitive layers in photoconverting devices.

The self-assembly of donor-acceptor linked fullero[60/70]pyrrolidines with a high substituted cobalt(II) phthalocyanine, namely, (octakis(3,5-di- tert -butylphenoxy)phthalocyaninato)cobalt(II) ( CoPc ) were investigated employing different spectroscopic methods (UV-vis, IR, 1 H NMR and MALDI-TOF) and chemical thermodynamics/kinetics. The fulleropyrrolidines with both different core symmetry (C 60 , C 70 ) and substitution by one, two or three pyridyl/imidazole groups were used as the electron acceptors in the composition of these dyads. The chemical structure and redox potentials determined by the cyclic voltammetry/amperometry method were obtained. The dependence of the dyad stability on the chemical structure of fullero[60/70]pyrrolidines was revealed. Prospects for the use of the dyads studied as the photoactive materials for further development of the applied chemistry of phthalocyanines were shown.

In this work, two porphyrins bearing [3,6-di-tert-butyl-carbazol-9-yl-benzoyloxy)]- (1) and [3,6-bis(3 ',6 '-di(tertbutyl)-9 ' H-carbazol)-9H-carbazolbenzoyloxy]phenyl (2) groups and their zinc (1Zn, 2Zn)/cobalt (1Co, 2Co) complexes were synthesized and studied by experimental and theoretical methods. The spectral parameters (UV-vis absorption/femtosecond transient absorption/fluorescence, IR, 1H NMR, mass spectra) of the compounds were observed. Their structure was also examined by the DFT method. The comparative study of the UV-vis spectra by the DFT/TDDFT calculation, and by the prediction of the Soret band maximum using machine learning methods, namely the consensus models based on the data of over 10000 porphyrin free bases and their complexes with metals was performed. The absorption maximum wavelength (Soret band) of porphyrins predicted with machine learning methods showed better agreement with the experimental data compared to the DFT/TDDFT calculation. The final consensus model is freely available at https://ochem.eu/article/145340 and can be used by the other researchers to obtain new functionalized porphyrins with desired optical properties.

In this study, the synthetic approach, structural characterization and optical properties of series of carbazole derivatives with different functional groups were investigated in order to provide the foundations and develop novel materials with required characteristics suitable for obtaining opto- and electrical devices. Such molecules can act as building blocks for more complex organic molecules. The compositions and structural characteristics of them were determined by the elemental analysis, infrared and NMR spectroscopy, mass-spectrometry, thermal analysis, UV/Vis and fluorescence spectroscopy. The geometry optimization of the most stable conformers was performed using TDDFT calculations which were also employed to gain insight into the experimental data. Optical measurements and computational studies imply that the compounds are non-planar due to steric repulsion of hydrogen atoms and take a curved conformation with angles 45.5°–55.9° between the carbazole and aryl substituents planes. All synthesized compounds have intense fluorescence in solution with quantum yields from 18% to 50% and exhibit solid state fluorescence from bluish-white to blue-green, that can be adjusted by introducing various substituents focusing on functionalization at the 3,6- and 9-positions.