Oxidative C-H/C-H Coupling of Dipyrromethanes with Azines by TiO2-Based Photocatalytic System. Synthesis of New BODIPY Dyes and Their Photophysical and Electrochemical Properties

Oxidative C-H/C-H coupling reactions of dipyrromethanes with azines in the presence of a heterophase oxidative photocatalytic system (O2/TiO2/visible light irradiation) were carried out. As a result of cyclization of obtained compounds with boron trifluoride etherate, new hetaryl-containing derivatives of 4,4-difluoro-4-boron-3a,4a-diaza-s-indacene were synthesized. For the obtained compounds, absorption and luminescence spectra, quantum yields of luminescence as well as cyclic volt-amperograms were measured.

Структура R-=SUB=-1-=/SUB=- и R-=SUB=-2-=/SUB=- полос изотопов иона Cr-=SUP=-3+-=/SUP=- в монокристалле рубина при комнатной температуре

The absorption and luminescence spectra of the R1 and R2 bands in a ruby Al2O3:Cr3+ (0,05%) single crystal at room temperature were studied. The luminescence bands have been obtained both by excitation of the crystal by the radiation of a halogen lamp and by selective excitation of the two upper levels of the 2T1 state using the radiation of a laser diode with a tunable wavelength (656-662 nm). In the spectra of selectively excited luminescence bands, four different displacements of the R1 and R2 bands and four different distances between these bands have been detected, the change of which is a multiple of ~ 0.52 cm-1. A detailed comparative analysis of the obtained spectra of the luminescence bands and their absorption allowed us to determine the combined structure of each of the R1 and R2 bands, formed by additional doublets of these bands of all four stable isotopes of ions 50Cr3+, 52Cr3+, 53Cr3+ and 54Cr3+. The splitting of the obtained doublets varies from 7.04 to 9.14 cm-1 depend on the mass of the isotope

Особенности спектральных характеристик различных структурных модификаций Lu-=SUB=-1-x-=/SUB=-RE-=SUB=-x-=/SUB=-BO-=SUB=-3-=/SUB=-

The structure, IR absorption and luminescence spectra of the microcrystals of Lu1-xEuxBO3, Lu0.99-xTbxEu0.01BO3, and Lu0.99−xYxEu0.01BO3 orthoborates (0 ≤ x ≤ 0.25) synthesized at 970°С were studied. An increase in х leads to a sequential change of the structural state of the orthoborates. At х ≤ 0.07 – 0.09, the compounds form a solid solution with the calcite structure and microcrystal size of 8 – 20 µm. Then, they become two-phase: the vaterite phase arises along with the calcite structure. At х ≥ 0.2 – 0.25, the entire bulk of a sample has the vaterite structure. A correspondence between the structure and spectral characteristics of these compounds was established. Luminescence spectra were investigated at different wavelengths of exciting light. This allowed obtaining information on the structure of a near-surface layer and the bulk of microcrystals of the investigated samples. It is shown that the vaterite phase arises both in the bulk of large microsrystals (8 – 20 µm) and in the form of small microsrystals (1 – 2 µm).

Solvatochromic effects in absorption and luminescence spectra and stability of emission quantum yield of carbon nanoparticles (part I)

The features of the solvatochromic effects of absorption (Ab) and photoluminescence (PL) spectra, as well as the quantum yield of emission (QYE) of carbon nanoparticles (CNPs) synthesized by various methods from a mixture of citric acid and nitrogen-containing precursors, in protic and aprotic solvents have been studied. It has been shown that the parameters of the spectra Ab, PL and the QYE value of particle solutions to a large extent depend on the method, conditions and modes of synthesis, the method of modification and separation of CNPs, the types and composition of precursors, and also the fundamental properties and pH of solvents. In solvents with a dielectric constant of 4.5 – 109.5, the QYE value of particles varies in a wide range from 10.8 to 100.0 %, and the PL band peak shifts from 466.4 to 536.8 nm. The presence of strong solvatochromic effects in the spectra of Ab and PL particles was shown, and the important role of the processes of protonation and deprotonation of surface groups of CNPs was established. The influence of universal and specific interactions on the spectroscopic parameters of CNPs has been investigated, and a significant contribution to the solvatochromic effects of specific interactions has been demonstrated.

Синтез и характеризация наночастиц CuIn-=SUB=-2-=/SUB=-S

CuInS2 nanoparticles were synthesized and coated with ZnS. The absorption and luminescence spectra of nanoparticles, as well as the dependencies of the luminescence spectra on temperature, the In/Cu ratio, and particle coating were obtained. It was shown that the properties of nanoparticles change over time after synthesis. The ripened CuInS2 / ZnS nanoparticles luminesce in the range of 600–850 nm. The coating of nanoparticles with a shell significantly increases the luminescence intensity. The obtained nanoparticles can be used as temperature sensors at deep incorporation into biological tissue.

Влияние индия на спектральные и структурные характеристики Lu-=SUB=-0.98-x-=/SUB=-In-=SUB=-x-=/SUB=-Eu-=SUB=-0.02-=/SUB=-BO-=SUB=-3-=/SUB=-

The structure and the IR absorption and luminescence spectra of the Lu0.98-хInхEu0.02BO3 orthoborates are studied at 0 ≤ x ≤ 0.1. The Lu1-xInxBO3 solid solution, which consists of lutetium borate LuBO3 having two stable structural modifications (calcite, vaterite) and indium orthoborate InBO3 having one structural modification (calcite), crystallizes at x = 0.1 to form a calcite structure almost throughout the volume. We showed that the structural transformations in the Lu0.98-хInхEu0.02BO3 orthoborates induced by an increase in the In3+ ion concentration begin in the near-surface layers of the orthoborate microcrystals. The amount of calcite increases in the sample volume with x, and calcite occupies 98% of the Lu0.88In0.1Eu0.02BO3 sample volume.