Modern Trends of Organic Chemistry in Russian Universities

© 2018, Pleiades Publishing, Ltd. This review is devoted to the scientific achievements of the departments of organic chemistry in higher schools of Russia within the past decade

Catalyzed M–C coupling reactions in the synthesis of s-(pyridylethynyl) dicarbonylcyclopentadienyliron complexes

The reactions between terminal ethynylpyridines, (trimethylsilyl)ethynylpyridines and cyclopentadienyliron dicarbonyl iodide were studied under Pd/Cu-catalyzed conditions to develop a synthetic approach to the σ-alkynyl iron complexes Cp(CO)(2)Fe–C[triple bond, length as m-dash]C–R (R = ortho-, meta-, para-pyridyl). Depending on the catalyst and reagents used, the yields of the desired σ-pyridylethynyl complexes varied from 40 to 95%. In some cases the reactions with ortho-ethynylpyridine gave as byproduct the unexpected binuclear FePd μ-pyridylvinylidene complex [Cp(CO)Fe{μ(2)-η(1)(C(α)):η(1)(C(α))-κ(1)(N)-C(α)[double bond, length as m-dash]C(β)(H)(o-C(5)H(4)N)}(μ-CO)PdI]. The conditions, catalysts, and reagents that provide the highest yields of the desired σ-pyridylethynyl iron compounds were determined. The methods developed allowed the synthesis of the corresponding σ-4-benzothiadiazolylethynyl complex Cp(CO)(2)Fe–C[triple bond, length as m-dash]C–(4-C(6)H(3)N(2)S) as well. Eventually, synthetic approaches to σ-alkynyl iron complexes of the type Cp(CO)(2)Fe–C[triple bond, length as m-dash]C–R (R = ortho-, meta-, para-pyridyl, 4-benzothiadiazol-2,1,3-yl) based on the Pd/Cu-catalyzed cross-coupling reactions were elaborated

Temperature dependent steric hindrance effects in triplet state relaxation of meso-phenyl-substituted Pd-octaethylporphyrins

The analysis of spectral-kinetic results of transient absorption and phosphorescence experiments has been carried out in a wide temperature range (80-293K) for a series of Pd-octaethylporphyrin derivatives (PdOEP) with increasing number of bulky meso-phenyl substituents. In order to elucidate the influence of steric hindrance interactions, as well as porphyrin macrocycle non-planarity on photophysical characteristics and relaxation pathways of triplet states, the following parameters were compared: i) T-state positions on the energy scale, ii) phosphorescence lifetimes and T1 -Tn transient absorption spectra, iii) phosphorescence quantum efficiencies, iv) activation energies of temperature-dependent phosphorescence rate constants for planar PdOEP and non-planar PdOEP-meso(Ph)n molecules

Temperature dependent steric hindrance effects in triplet state relaxation of meso-phenyl-substituted Pd-octaethylporphyrins

The analysis of spectral-kinetic results of transient absorption and phosphorescence experiments has been carried out in a wide temperature range (80-293K) for a series of Pd-octaethylporphyrin derivatives (PdOEP) with increasing number of bulky meso-phenyl substituents. In order to elucidate the influence of steric hindrance interactions, as well as porphyrin macrocycle non-planarity on photophysical characteristics and relaxation pathways of triplet states, the following parameters were compared: i) T-state positions on the energy scale, ii) phosphorescence lifetimes and T1 -Tn transient absorption spectra, iii) phosphorescence quantum efficiencies, iv) activation energies of temperature-dependent phosphorescence rate constants for planar PdOEP and non-planar PdOEP-meso(Ph)n molecules

Molecular Structure of Nickel Octamethylporphyrin—Rare Experimental Evidence of a Ruffling Effect in Gas Phase

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