Crown-hydroxylamines are pH-dependent chelating N,O-ligands with a potential for aerobic oxidation catalysis.

Despite the rich coordination chemistry, hydroxylamines are rarely used as ligands for transition metal coordination compounds. This is partially because of the instability of these complexes that undergo decomposition, disproportionation and oxidation processes involving the hydroxylamine motif. Here, we design macrocyclic poly-N-hydroxylamines (crown-hydroxylamines) that form complexes containing a d-metal ion (Cu(II), Ni(II), Mn(II), and Zn(II)) coordinated by multiple (up to six) hydroxylamine fragments.

Phosphine-NHC-Phosphonium Ylide Pincer Ligand: Complexation with Pd(II) and Unconventional -Coordination of the Ylide Moiety.

An efficient synthesis of two pincer preligands [PhPCH(R)ImCHCHCHPPh]X (R = H, X = OTf; R = Ph, X = BF) was developed. Subsequent reactions with PdCl and an excess of CsCO led to the formation of highly stable cationic metalated Pd(II) complexes [(,,,)Pd]X exhibiting phosphine, NHC, phosphonium ylide, and σ-aryl donor extremities. The protonation of one of the latter complexes with R = H affords the Pd(II) complex [(,,)Pd(MeCN)](OTf) bearing an unprecedented nonsymmetrical NHC core pincer scaffold with a 5,6-chelating framework.

A synthetic route to artificial chiral α-amino acids featuring a 3,4-dihydroisoquinolone core through a Rh(III)-catalyzed functionalization of allyl groups in chiral Ni(II) complexes.

Currently, 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.

Gel Based on Hydroxyethyl Starch with Immobilized Amikacin for Coating of Bone Matrices in Experimental Osteomyelitis Treatment.

A polysaccharide gel containing covalently bound amikacin, a broad-spectrum antibiotic, was produced by using epichlorohydrin-activated hydroxyethyl starch (HES). The structure of the polymers was analyzed by C and H nuclear magnetic resonance (C NMR and H NMR) and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. The sites of covalent attachment of amikacin to the epoxypropyl substituent and the HES backbone were determined.

Effect of Composition and Surface Microstructure in Self-Polarized Ferroelectric Polymer Films on the Magnitude of the Surface Potential.

The values of the surface potentials of two sides of films of polyvinylidene fluoride, and its copolymers with tetrafluoroethylene and hexafluoropropylene, were measured by the Kelvin probe method. The microstructures of the chains in the surfaces on these sides were evaluated by ATR IR spectroscopy. It was found that the observed surface potentials differed in the studied films.

C(21)-Di- and monofluorinated scaffold for thevinol/orvinol-based opioid receptor ligands.

Defluorination of the readily available 21,21,21-trifluorothevinone (7) with Mg + MeSiCl allows the preparation of 21,21-difluorothevinone (10) and 21-fluorothevinone (11), which can be used as the starting compounds for syntheses of 21,21-difluoro- and 21-fluoro-substituted relatives of thevinols and orvinols. Taken together, thevinols and orvinols are well known to constitute a family of the highly potent 4,5α-epoxy-18,19--(etheno/ethano)morphinan-type opioid receptor ligands. Alternatively, 10 and 18,19-dihydro-21,21-difluorothevinone (13) have been synthesized by the addition of MeSiCHF to the carbonyl function of thevinal (12) and dihydrothevinal (18) followed by oxidation of the intermediate C(21)-difluorinated secondary alcohols.

Precise Fingerprint Determination of Vibrational Infrared Spectra in a Series of Co(II) Clathrochelates through Experimental and Theoretical Analyses.

The energetic demands of modern society for clean energy vectors, such as H, have caused a surge in research associated with homogeneous and immobilized electrocatalysts that may replace Pt. In particular, clathrochelates have shown excellent electrocatalytic properties for the hydrogen evolution reaction (HER). However, the actual mechanism for the HER catalyzed by these -metal complexes remains an open debate, which may be addressed via Operando spectroelectrochemistry.

Rhodium complexes with planar-chiral cyclopentadienyl ligands: synthesis from -butylacetylene and catalytic performance in C-H activation of arylhydroxamates.

The rhodium complex [(CHBuCHBu)RhCl] with an asymmetric cyclopentadienyl ligand was prepared in 95% yield by the reaction of [(cod)RhCl] with -butylacetylene in the presence of AlCl. A similar reaction in the presence of InBr gave the cationic fulvene complex [(CHBu = CHBu)Rh(cod)]InBr (70%), which can add alcohols ROH and produce more bulky catalysts [(CHBuCH(OR)Bu)RhCl]. The enantiomers of these planar-chiral complexes were separated by thin-layer chromatography in the presence of L-phenylglycinol.

Development of a Gadolinium-Boron-Conjugated Albumin for MRI-Guided Neutron Capture Therapy.

Noninvasive monitoring of boron agent biodistribution is required in advance of neutron capture therapy. In this study, we developed a gadolinium-boron-conjugated albumin (Gd-MID-BSA) for MRI-guided neutron capture therapy. Gd-MID-BSA was prepared by labeling bovine serum albumin with a maleimide-functionalized gadolinium complex and a maleimide-functionalized -dodecaborate orthogonally.

Nickel(II) and Palladium(II) Complexes with η:κ()-Coordinated Dicarbollide Ligands Containing Pendant Pyridine Group.

A series of - and -substituted -carborane derivatives with a pendant pyridyl group was prepared. The synthesized compounds were used as ligands in the complexation reactions with bis(triphenylphosphine)nickel(II) and palladium(II) chlorides to give six new metallacomplexes with unusual η:κ()-coordination of the metal center. The single crystal structures of 1-(NCH-2'-S)-1,2-CBH, 1-(NCH-2'-CHS)-1,2-CBH, Cs [7-(NCH-2'-CHS)-7,8-CBH] - and -carboranes and 3-PhP-3-(4(7)-NCH-2'-S)--3,1,2-NiCBH and 3-PhP-3-(4(7)-NCH-2'-CHS)--3,1,2-NiCBH metallacarboranes were determined using single crystal X-ray diffraction.

Optical and Electrochemical Properties of a Photosensitive Pyromellitic Diimide Derivative of Cymantrene.

Photochemical properties of symmetrical pyromellitic diimide containing two cymantrenyl fragments at two nitrogen atoms were studied with IR, NMR, UV-vis, ESI-MS, and cyclic voltammetry. It was found that new unstable chelates are formed during photolysis. At the same time, the CO ligand dissociates from two Mn(CO) fragments during photoexcitation, which dramatically changes the electronic and redox properties of the molecule compared to the cymantrene derivative containing one imide fragment.

Adaptive carbonyl umpolung involving a carbanionic carbene Breslow intermediate: an alternative mechanism for NHC-mediated organocatalysis.

Herein, we propose a novel mechanistic model for NHC-mediated carbonyl umpolung which involves the formation of a carbanionic carbene Breslow intermediate (CCBI). We have demonstrated theoretically that this reactive intermediate can be formed by inserting an aldehyde into the C4-H position of an -aryl-substituted imidazolium-derived NHC the generation of an H-bonded ditopic carbanionic NHC (NHC). Our DFT study on benzoin condensation has revealed that the mechanism of polarity inversion proceeding through the CCBI may be more energetically favorable than the classical mechanism of umpolung that uses the C2 carbene position in NHC.

Reductive coupling of nitroarenes with carboxylic acids - a direct route to amide synthesis.

A straightforward and selective way for the preparation of amides from nitroarenes and carboxylic acids using carbon monoxide as a reductant was developed. This protocol does not require any non-gaseous additives, thus simplifying product isolation. Aliphatic carboxylic acid was modified in the presence of aromatic ones, and reducible functional groups such as CC, Ar-Br, and R-NO were saved.

Aerogel-Like Material Based on PEGylated Hyperbranched Polymethylethoxysiloxane.

Aerogels are a class of materials that have gained increasing attention over the past several decades due to their exceptional physical and chemical properties. These materials are highly porous, with a low density and high surface area, allowing for applications such as insulation, catalysis, and energy storage. However, traditional aerogels, such as pure silica aerogels, suffer from brittleness and fragility, which limit their usefulness in many applications.

(Aminoalkyl)diphenylphosphine sulfides: synthesis and application as building blocks in the design of multidentate ligands for cytotoxic Pd(II) complexes.

Amino-functionalized phosphoryl compounds are among the most useful molecular scaffolds in medicinal chemistry, while the potential of their thiophosphorylated analogs, especially those having an alkylamino moiety, is still uncovered. This is mainly due to the lack of convenient synthetic routes to these organophosphorus derivatives. To address this issue, we have suggested the facile approaches to α-(aminomethyl)- and substituted/unsubstituted α-(aminobenzyl)diphenylphosphine sulfides based on either the sequential transformations of (hydroxymethyl)diphenylphosphine sulfide, with the Staudinger reaction of an azide derivative as the key stage, or the addition of PhP(S)H to hydrobenzamides followed by the acid hydrolysis.

Self-assembly of a metal-organic cage-like structure bearing cofacial redox-active bis-(-semiquinone) copper(II) units.

Ditopic di--quinone with a resorcinol bridge exhibits the ability to self-assemble in a reaction with copper, giving a cage-like binuclear complex that, due to the cofacially placed metal ions, is capable of encapsulation of different solvent molecules as guest ligands. Notably, the geometry of the internal cavity of this complex adjusts depending on the coordinating properties of the encapsulated molecule (mono- or bidentate). A feature of this species is that the cage-forming units are copper(II) bis-semiquinonate moieties, capable of undergoing ligand-centered redox transformations.

New 2,4-dihydro-1H-1,2,4-triazole-3-selones and 3,3'-di(4H-1,2,4-triazolyl)diselenides. Synthesis, biological evaluation, and in silico studies as antibacterial and fungicidal agents.

The reaction of aromatic ring-substituted isoselenocyanates with 2-thiopheacetic and 4-pyridinecarboxylic acid hydrazides yielded selenosemicarbazides which were further converted into previously unknown 1,2,4-triazole-3-selones and 3,3'-di(4H-1, 2,4-triazolyl)diselenides. The structures of the obtained compounds were studied by NMR spectroscopy, IR spectroscopy, and high-resolution mass spectroscopy (HR-MS). The bactericidal and fungicidal activity of some obtained compounds was evaluated in molecular modeling studies such as docking and simulation studies.

A larger basis set describes atomization energy core-valence correction better than a higher-order coupled-cluster method.

The accuracy of coupled-cluster methods for the computation of core-valence correction to atomization energy was assessed. Truncation levels up to CCSDTQP were considered together with (aug-)cc-pwCVZ ( = D, T, Q, 5) basis sets and three different extrapolation techniques (canonical and flexible Helgaker formula and Riemann zeta function extrapolation). With the exception of CCSD, a more accurate correction can be obtained from a larger basis set using a lower-level coupled-cluster method, and not .

3D-Shaped Binders of Unfolded Proteins Inducing Cancer Cell-Specific Endoplasmic Reticulum Stress In Vitro and In Vivo.

The amount of unfolded proteins is increased in cancer cells, leading to endoplasmic reticulum (ER) stress. Therefore, cancer cells are sensitive to drugs capable of further enhancing ER stress. Examples of such drugs include the clinically approved proteosome inhibitors bortezomib and carfilzomib.

Abiraterone Acetate Complexes with Biometals: Synthesis, Characterization in Solid and Solution, and the Nature of Chemical Bonding.

Abiraterone acetate (AbirAc) is the most used steroidal therapeutic agent for treatment of prostate cancer. The mainly hydrophobic molecular surface of AbirAc results in its poor solubility and plays an important role for retention of abiraterone in the cavity of the receptor formed by peptide chains and heme fragments. In order to evaluate the hydrolytic stability of AbirAc, to modify its solubility by formation of new solid forms and to model bonding of this medication with the heme, a series of d-metal complexes with AbirAc was obtained.

New Boron Containing Acridines: Synthesis and Preliminary Biological Study.

The synthesis of the first conjugates of acridine with cobalt bis(dicarbollide) are reported. A novel 9-azido derivative of acridine was prepared through the reaction of 9-methoxyacridine with NCHCHNH, and its solid-state molecular structure was determined via single-crystal X-ray diffraction. The azidoacridine was used in a copper (I)-catalyzed azide-alkyne cycloaddition reaction with cobalt bis(dicarbollide)-based terminal alkynes to give the target 1,2,3-triazoles.

Composites and Materials Prepared from Boron Cluster Anions and Carboranes.

Here, we present composites and materials that can be prepared starting with boron hydride cluster compounds (decaborane, decahydro--decaborate and dodecahydro--dodecaborate anions and carboranes). Recent examples of their utilization as boron protective coatings including using them to synthesize boron carbide, boron nitride, metal borides, metal-containing composites, and neutron shielding materials are discussed. The data are generalized demonstrate the versatile application of materials based on boron cluster anions and carboranes in various fields.

A Family of Cagelike Mn-Silsesquioxane/Bathophenanthroline Complexes: Synthesis, Structure, and Catalytic and Antifungal Activity.

This study reports a novel family of cage manganesesilsesquioxanes prepared via complexation with bathophenanthroline (4,7-diphenyl-1,10-phenanthroline). The resulting Mn-, MnLi-, and MnNa-compounds exhibit several unprecedented cage metallasilsesquioxane structural features, including intriguing self-assembly of silsesquioxane ligands. Complexes were tested for fungicidal activity against seven classes of phytopathogenic fungi.

Decaborane: From Alfred Stock and Rocket Fuel Projects to Nowadays.

The review covers more than a century of decaborane chemistry from the first synthesis by Alfred Stock to the present day. The main attention is paid to the reactions of the substitution of hydrogen atoms by various atoms and groups with the formation of -polyhedral boron-halogen, boron-oxygen, boron-sulfur, boron-nitrogen, boron-phosphorus, and boron-carbon bonds. Particular attention is paid to the chemistry of -borane -[BH], whose structure is formed by two decaborane moieties with a common edge, the chemistry of which has been intensively developed in the last decade.

Tetranuclear lanthanide-based silsesquioxanes: towards a combination of a slow relaxation of the magnetization and a luminescent thermometry.

Lanthanide-based silsesquioxanes constitute an emerging family of cage-like metallasilsesquioxanes with exciting optical and magnetic properties. We report here the synthesis, structures and luminescence properties of a series of tetranuclear lanthanide-silsesquioxane compounds of general formula [NEt][(PhSiO)(Ln/Ln')(NO)(EtOH)(MeCN)]·4(MeCN) with different lanthanide ions (where Ln/Ln' = Dy/Eu (1), Dy/Tb (2) and Eu/Tb/Y (3)) and investigate the impact of the lanthanide ions combination on magnetic and photo-luminescent properties. Compound 1 behaves as a field-induced Single Molecule Magnet (SMM) and presents temperature-dependent luminescence characteristics of Eu making it an emissive thermometer working in the temperature range 293-373 K with the maximum relative sensitivity of 1.