Victor E. Pushkarev

A highly stable double-coordinated 2-hydroxy-tri(tert-butyl)-substituted zinc phthalocyanine dimer: synthesis, spectral study, thermal stability and electrochemical properties

A highly stable J-type dimer based on 2-hydroxy-tri(tert-butyl)-substituted zinc phthalocyanine with specific supramolecular architecture was investigated by UV-visible and fluorescence spectroscopy and by cyclic voltammetry to show strong π–π interactions and coordination between hydroxy-groups and Zn2+ central metal ions. The possibility of controlling the fluorescent properties of the obtained complex by using different solvents is demonstrated, which, along with the high thermal stability according to the thermoanalytical study, may increase practical applicability of supramolecular dimeric phthalocyanine compounds.

Bis(tetrabenzotriazaporphyrinato) and (tetrabenzotriazaporphyrinato)(phthalocyaninato) lutetium(III) complexes – novel sandwich-type tetrapyrrolic ligand based NIR absorbing electrochromes

The first sandwich-type complexes have been prepared for tetrabenzotriazaporphyrin ligands. The compounds reveal intrinsic UV-Vis/NIR absorption as well as peculiar electrochromic behavior. The heteroleptic (tetrabenzotriazaporphyrinato)(phthalocyaninato) lutetium derivative shows intermediate spectral and electrochemical properties with respect to homoleptic relatives.

Directed synthesis of bi- and polynuclear clamshell-type phthalocyanines and their physico-chemical investigations

Novel bi-, tri- and tetranuclear butyl- and tert-butyl-substituted clamshell-type phthalocyanines were synthesized starting from 2-hydroxyphthalocyanines with quantitative yields. The structures of the obtained compounds were characterized by a complex of NMR spectroscopy and mass spectrometry techniques. Applying electronic absorption spectroscopy (UV-vis) and density functional theory (DFT) showed the complicated conformation equilibria for the spacer-bonded macrocyclic compounds and led us to estimate their behavior dependent on the number and relative orientation of macrocycles.

Synthesis and spectral properties of new planar binuclear phthalocyanines sharing the benzene ring

New planar binuclear phthalocyanines sharing the benzene ring were synthesized and their spectral properties were studied. Intense absorption in the near-IR region (∼850 nm) was observed for the first time.

Self-assembly of 2-hydroxy-tri-tert-butylphthalocyaninato zinc into J-type dimer: UV-vis, DFT and spectropotentiometric study

The role of the base nature during complexation of 2-hydroxy-9(10),16(17),23(24)-tri-tert-butyl-29H,31H-phthalocyanine ligand (1) with zinc acetate was studied by the UV-vis spectroscopy and DFT calculations. The latter allowed us to explain the selective formation of double-coordinated J-type dimer in the presence of lithium methoxide. Spectropotentiometry was used to study the nucleophilic properties of the dimeric complex in comparison with the corresponding monomer and has demonstrated the strong intramolecular interactions of macrocycles.

Photoluminescence in semiconductor structures based on butyl-substituted erbium phthalocyanine complexes

The study is concerned with the luminescence properties of ensembles of semiconductor structures containing organic phthalocyanine molecules with erbium ions as complexing agents. The photoluminescence spectra of the structures of the type of erbium monophthalocyanine, bisphthalocyanine, and triphthalocyanine are recorded. The photoluminescence peaks are detected at the wavelengths 888, 760, and 708 nm (and photon energies 1.4, 1.6, and 1.75 eV) corresponding to electronic transitions within the organic complexes. It is found that, when a metal complexing agent is introduced into the molecular structure of the ligand, the 708 nm luminescence peak becomes unobservable. It is shown that, in the bisphthalocyanine samples, the photoluminescence signal corresponding to transitions from the 4F9/2 level of erbium ions is enhanced.

The first synthesis of sandwich-type complex based on tetradiazepinoporphyrazine ligand

Sandwich-type complex based on tetradiazepinoporphyrazine ligand — bis{tetrakis(5,7-di(4-tert-butylphenyl)-6H-1,4-diazepino)[2,3-b,g,l,q]porphyrazinato}lutetium — was synthesized for the first time. The structure of the compound has been confirmed by UV-vis/NIR, 1H NMR spectroscopy, and MALDI-TOF mass spectrometry data. The introduction of annulated diazepine heterocycles to porphyrazine molecule significantly changes macrocycle reactivity and results in sandwich-type complex under conditions used for the selective synthesis of lanthanide(III) monophthalocyanines.

Synthesis of phthalocyanine compounds bearing 2-(diethoxyphosphoryl)-4-methylpenta-1,3-dienyl functional groups

Free-base phthalocyanine ligands and their zinc derivatives representing functionally monosubstituted (A3B type) or tetrasubstituted (A4 type) compounds with 2-diethoxyphosphoryl-4-methylpenta-1,3-dienyl moieties have been synthesized for the first time. Their structures were characterized by MALDI-TOF mass-spectrometry as well as 1H and 31P NMR spectroscopy data. A tendency to aggregation in dependence on the nature of the solvent was demonstrated as well.

Vibronic properties of organic semiconductors based on phthalocyanine complexes with asymmetrically distributed electron density

This study is concerned with the optical properties of organic semiconductors based on lanthanide (III) biphthalocyanine and triphthalocyanine complexes with asymmetrically distributed electron density. The ClPcLutBuPc biphthalocyanine and ClPcEuBuPcLuBuPc triphthalocyanine solid films (ClPc = 2, 3, 9, 10, 16, 17, 23, 24-octachlorophthalocyaninate, tBuPc = 2(3), 9(10), 16(17), 23(24)-tetra- tretbutylphthalocyani-nate, BuPc = 2, 3, 9, 10, 16, 17, 23, 24-octabutylphthalo cyaninate) are fabricated, and their transmittance spectra in the middle infrared region are studied. Analysis of the transmittance spectra shows that the addition of complexity to phthalocyanine molecules yields some changes in the spectra. Specifically, the isoindole group can exhibit vibronic properties in the form of four absorption lines in the range 1400–1450 cm-1. New absorption lines that may be due to chlorine-carbon bonds are observed in the far-infrared region.

Cerium bis(tetradiazepinoporphyrazinate): synthesis and peculiarities of spectral and electrochemical behavior

Bis{tetrakis(5,7-bis(4-tert-butylphenyl)-6H-1,4-diazepino)[2,3-b,g,l,q]porphyrazinato} cerium has been prepared for the first time via two alternative synthetic pathways: template macrocyclization of 5,7-bis(4-tert-butylphenyl)-6H-1,4-diazepine-2,3-dicarbonitrile and direct complexation employing its cyclic tetramer, a free-base porphyrazine ligand. A combination of HRMS, UV-Vis, FT-IR and NMR spectroscopic methods allowed the identification of the tetravalent oxidation state of cerium ion in the double-decker obtained. Unlike Pc2CeIV (Pc2− = phthalocyaninate anion), the compound revealed a complicated UV-Vis spectrum that demonstrated a strong solvent dependence. A comparative electrochemical study of the cerium complex and the corresponding free-base ligand was carried out. Ligand-centered processes are diffusion controlled, whereas Ce4+/3+ transformation is characterized by slow electron transfer kinetics. This is as a result of poor accessibility of the metal center to an electrode surface due to the presence of bulky ligands, as well as a considerable structural rearrangement of the sandwich molecule.