The tetrapyrrolic macrocycle as a scaffold for various chemical modifications provides broad opportunities for the preparation of complex multifunctional conjugates suitable for binary antitumor therapies. Typically, illumination with monochromatic light triggers the photochemical generation of reactive oxygen species (ROS) (photodynamic effect). However, more therapeutically valuable effects can be achieved upon photoactivation of tetrapyrrole derivatives.
View Article and Find Full Text PDFA series of structurally similar trinuclear macrocyclic copper(I) and silver(I) pyrazolate complexes bearing various short-bite diphosphine RPCH(R')PR ligands are reported. Upon diphosphine coordination, the planar geometry of the initial complexes undergoes bending along the line between two metal atoms coordinated to the phosphorus moieties. The complexes based on dcpm ligands (R = cyclohexyl, R' = H, Ph) do not exhibit dynamic behavior in solution at room temperature on the P NMR time scale as it was previously observed for similar trinuclear copper complexes bearing the dppm (R = Ph, R' = H) scaffold.
View Article and Find Full Text PDFRev Sci Instrum
July 2024
Laser-Induced Fluorescence (LIF) spectroscopy is an essential tool for probing ion and atom velocity distribution functions (VDFs) in complex plasmas. VDFs carry information about the kinetic properties of species that is critical for plasma characterization. Accurate interpretation of these functions is challenging due to factors such as multicomponent distributions, broadening effects, and background emissions.
View Article and Find Full Text PDFAn efficient access to the novel 5-(aryl)amino-1,2,3-triazole-containing 2,1,3-benzothiadiazole derivatives has been developed. The method is based on 1,3-dipolar azide-nitrile cycloaddition followed by Buchwald-Hartwig cross-coupling to afford the corresponding -aryl and ,-diaryl substituted 5-amino-1,2,3-triazolyl 2,1,3-benzothiadiazoles under NHC-Pd catalysis. The one-pot diarylative Pd-catalyzed heterocyclization opens the straightforward route to triazole-linked carbazole-benzothiadiazole D-A systems.
View Article and Find Full Text PDFCyclic trinuclear Ag(I) pyrazolate interacts with phenylacetylene forming a mix-ligand complex in which one pyrazolate ligand is changed to phenylethynide. The CC fragment coordinates only to two silver(I) atoms one carbon atom demonstrating unique μ-η σ-coordination with close Ag-C bond lengths and Ag-C-C angles. The complex exhibits blue emission under UV irradiation.
View Article and Find Full Text PDFAn efficient method of accessing new CF-containing spiro-[indene-proline] derivatives has been developed based on a Cp*Rh(III)-catalyzed tandem C-H activation/[3+2]-annulation reaction of 5-aryl-2-(trifluoromethyl)-3,4-dihydro-2-pyrrole-2-carboxylates with alkynes. An important feature of this spiro annulation process is the feasibility of dehydroproline moiety to act as a directing group in the selective activation of the aromatic C-H bond.
View Article and Find Full Text PDFCurrently, non-proteinogenic α-amino acids (α-AAs) have attracted increasing interest in bio- and medicinal chemistry. In this context, the first protocol for the asymmetric synthesis of artificial α-AAs featuring a 3,4-dihydroisoquinolone core with two stereogenic centers was successfully elaborated. A straightforward Rh(III)-catalysed C-H activation/annulation reaction of various aryl hydroxamates with a set of robust and readily available chiral Ni(II) complexes, which have allylic appendages derived from glycine (Gly), alanine (Ala) and phenylalanine (Phe), allowed incorporation of a 3,4-dihydroisoquinolone scaffold into the chiral amino acid residue.
View Article and Find Full Text PDFAn efficient approach for the preparation of 3,5-dicarborane-substituted BODIPY conjugates was developed the functionalization of 3,5-dibromo-8-pentafluorophenyl-BODIPY with neutral and anionic carborane -nucleophiles. It was found that 3,5-dicarborane-substituted BODIPYs could be easily modified with a third carborane cluster using SAr substitution reactions of the -fluorine atom in the -pentafluorophenyl BODIPY substituent with the corresponding carborane -nucleophile affording boron-enriched BODIPYs in good yields. The influence of bromine atom substitution with carborane moieties on the position of absorption and fluorescence bands and the fluorescence quantum yields of the prepared BODIPYs were analyzed.
View Article and Find Full Text PDFCorrection for 'An asymmetric metal-templated route to amino acids with an isoquinolone core a Rh(III)-catalyzed coupling of aryl hydroxamates with chiral propargylglycine Ni(II) complexes' by Mikhail A. Arsenov , , 2022, , 9385-9391, https://doi.org/10.
View Article and Find Full Text PDFThevinols and their 3-O-demethylated relatives, orvinols, are derivatives of the Diels-Alder adduct of natural alkaloid thebaine with methyl vinyl ketone. Taken together, thevinols and orvinols constitute an important family of opioid receptor (OR) ligands playing an important role in both the OR mediated antinociception and OR antagonism. Herein, we disclose for the first time the OR activity of orvinols fluorinated within the pharmocophore associated with C(20) and its surrounding along with a dependence of the activity profile on the substituent at N(17).
View Article and Find Full Text PDFA reaction of a cyclic trinuclear copper(I) or silver(I) pyrazolate complex ([MPz], M = Cu, Ag) with 1,1'-dimethyl-2,2'-bibenzimidazole () leads to the formation of tetranuclear adducts decorated by one or two molecules of a diimine ligand, depending on the amount of the ligand added (0.75 or 1.5 equivalents).
View Article and Find Full Text PDFA general protocol for the asymmetric synthesis of artificial amino acids (AAs) comprising an isoquinolone skeleton was successfully elaborated a straightforward Rh(III)-catalyzed C-H activation/annulation of various aryl hydroxamates with a series of robust chiral propargylglycine Ni(II) complexes derived from glycine (Gly), alanine (Ala) and phenylalanine (Phe) in a green solvent (methanol) under mild conditions (at room temperature under air). Notably, in the case of phenylalanine-derived complexes, the formation of unfavorable 4-substituted isoquinolone regioisomers was achieved by a catalyst control for the first time. The subsequent acidic decomposition of the obtained Ni(II) complexes provides the target unnatural α- and α,α-disubstituted AAs with an isoquinolone core in an enantiopure form.
View Article and Find Full Text PDFThe structure, thermodynamic parameters, and the character of thermal motion in octamethylcyclotetrasiloxane (D4) were investigated using the combination of experimental (single-crystal X-ray diffraction, thermochemistry) and theoretical (density functional theory calculations, ab initio molecular dynamics and metadynamics) methods. Single crystals of D4 were grown in a glass capillary in situ and the structures of high- (238-270 K) and low-temperature (100-230 K) phases were studied in detail. In the temperature interval 230-238 K, a phase transition with rather low enthalpy (-1.
View Article and Find Full Text PDFA practically useful protocol for the asymmetric synthesis of artificial β-aryl-substituted cysteine derivatives was developed through sequential Pd(II)-catalyzed Heck cross-coupling with aryl iodides and hydrothiolation reaction with various alkyl thiols in the presence of triethylamine taking place in the ligand sphere of a robust and bench-stable chiral dehydroalanine Ni(II) complex. The subsequent acidic decomposition of the single diastereomeric Ni(II) complexes led to the target enantiopure cysteine derivatives.
View Article and Find Full Text PDFA family of well-defined Λ- and Δ-diastereomeric octahedral cationic chiral-at-cobalt complexes were obtained by a simple two-step reaction of (,)-1,2-diaminocyclohexane, (,)-1,2-diphenylethylenediamine, or ()-2-(aminomethyl)pyrrolidine and substituted salicylaldehydes with a cobalt(III) salt. It was observed for the first time that the use of an excess of cobalt(III) salt provides both the enantiopure Λ and Δ forms of the corresponding cobalt(III) complexes and in a ratio of diastereomers ranging from 1:1.6 to >20:1 (Λ/Δ) and in 31-95% combined yields.
View Article and Find Full Text PDFA series of emissive Cu(I) cationic complexes with 3-(2-pyridyl)-5-phenyl-pyrazole and various phosphines: dppbz (), Xantphos (), DPEPhos (), PPh (), and BINAP () were designed and characterized. Complexes obtained exhibit bright yellow-green emission (ca. 520-650 nm) in the solid state with a wide range of QYs (1-78%) and lifetimes (19-119 µs) at 298 K.
View Article and Find Full Text PDFHere we report the first synthesis of two diastereomeric cationic octahedral Co(III) complexes based on commercially available (,)-1,2-diphenylethylenediamine and salicylaldehyde. Both diastereoisomers with opposite chiralities at the metal center (Λ and Δ configurations) were prepared. The new Co(III) complexes possessed both acidic hydrogen-bond donating (HBD) NH moieties and nucleophilic counteranions and operate as bifunctional chiral catalysts for the challenging kinetic resolution of terminal and disubstituted epoxides by the reaction with CO under mild conditions.
View Article and Find Full Text PDFAliphatic artificial α-amino acids (α-AAs) have attracted great interest in biochemistry and pharmacy. In this context, we developed a promising practical protocol for the asymmetric synthesis of these α-AAs through the selective and efficient intermolecular cross-electrophile coupling of Belokon's chiral dehydroalanine Ni(ii) complex with different alkyl and perfluoroalkyl iodides mediated by a dual Zn/Cu system. The reaction afforded diastereomeric complexes with dr up to 21.
View Article and Find Full Text PDFThis study reports intriguing features in the self-assembly of cage copper(II) silsesquioxanes in the presence of air. Despite the wide variation of solvates used, a series of prismatic hexanuclear Cu cages (-) were assembled under mild conditions. In turn, syntheses at higher temperatures are accompanied by side reactions, leading to the oxidation of solvates (methanol, 1-butanol, and tetrahydrofuran).
View Article and Find Full Text PDFThe acid-base neutralization reaction of commercially available disodium 2,6-naphthalenedisulfonate (NDS, 2 equivalents) and the tetrahydrochloride salt of tetrakis(4-aminophenyl)methane (TAPM, 1 equivalent) in water gave a novel three-dimensional charge-assisted hydrogen-bonded framework (CAHOF, ). The framework was characterized by X-ray diffraction, TGA, elemental analysis, and H NMR spectroscopy. The framework was supported by hydrogen bonds between the sulfonate anions and the ammonium cations of NDS and protonated TAPM moieties, respectively.
View Article and Find Full Text PDFAn amendment to this paper has been published and can be accessed via a link at the top of the paper.
View Article and Find Full Text PDFAn efficient protocol was developed for the synthesis of π-extended isocoumarins and polycyclic aromatic hydrocarbons based on the oxidative coupling of aromatic carboxylic acids with internal alkynes catalyzed by (cyclopentadienyl)rhodium complexes. The coupling chemoselectivity strongly depends on whether Cp or the methylated Cp* ligands are used. The pentamethyl derivative [Cp*RhCl ] predominantly gives isocoumarins, while the non-methylated complex [CpRhI ] produces naphthalene derivatives.
View Article and Find Full Text PDFMycobacterium tuberculosis Beijing B0/W148 is one of the most widely distributed clusters in the Russian Federation and in some countries of the former Soviet Union. Recent studies have improved our understanding of the reasons for the "success" of the cluster but this area remains incompletely studied. Here, we focused on the system omics analysis of the RUS_B0 strain belonging to the Beijing B0/W148 cluster.
View Article and Find Full Text PDFChiral copper(II) and cobalt(III) complexes (- and , respectively) derived from Schiff bases of ()-2-(aminomethyl)pyrrolidine and salicylaldehyde derivatives were employed in a mechanistic study of the Henry reaction-type condensation of nitromethane and -nitrobenzaldehyde in CHCl (CDCl), containing different amounts of water. The reaction kinetics was monitored by H and C NMR. The addition of water had a different influence on the activity of the two types of complexes, ranging from a crucial positive effect in the case of the copper(II) complex to insignificant in the case of the stereochemically inert cobalt(III) complex .
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