Ca(II) and Yb(II) complexes featuring M(C≡C) structural motif: enforced proximity or genuine η -bonding?

Bis(carbazolide) complexes M[3,6-tBu -1,8-(RC≡C) Carb] (THF) (R=SiMe , n=0, M=Ca, Yb; R=Ph, n=1, M=Ca, Yb; n=0, M=Yb) were synthesized through transamination reaction of M[N(SiMe ) ] (THF) with two molar equivalents of carbazoles. The complexes feature M(η -C≡C) structural motif composed of M(II) ions encapsulated by four acetylene fragments due to atypical for alkaline- and rare-earth metals η -interactions with triple C≡C bond. This interaction is evidenced experimentally by X-ray diffraction, Raman spectroscopy in the solid state and by NMR-spectroscopy in the solution.

Conformational Analysis of 1,5-Diaryl-3-Oxo-1,4-Pentadiene Derivatives: A Nuclear Overhauser Effect Spectroscopy Investigation.

1,5-Diaryl-3-Oxo-1,4-Pentadiene derivatives are intriguing organic compounds with a unique structure featuring a pentadiene core, aryl groups, and a ketone group. This study investigates the influence of fluorine atoms on the conformational features of these derivatives in deuterated chloroform (CDCl) solution. Through nuclear magnetic resonance (NMR) spectroscopy and quantum chemical calculations, we discerned variations in interatomic distances and established predominant conformer proportions.

Synthesis of CF-Containing Spiro-[Indene-Proline] Derivatives via Rh(III)-Catalyzed C-H Activation/Annulation.

An 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.

Highly Selective CO Hydrogenation to Methanol over Complex In/Co Catalysts: Effect of Polymer Frame.

The growing demand for new energy sources governs the intensive research into CO hydrogenation to methanol, a valuable liquid fuel. Recently, indium-based catalysts have shown promise in this reaction, but they are plagued by shortcomings such as structural instability during the reaction and low selectivity. Here, we report a new strategy of controlling the selectivity and stability of bimetallic magnetically recoverable indium-based catalysts deposited onto a solid support.

Planar Chiral Rhodium Complex Based on the Tetrahydrofluorenyl Core for Enantioselective Catalysis.

A simple four-step route to a chiral tetrahydrofluorenyl rhodium catalyst from naturally occurring (-)-α-pinene was developed. Our approach does not use multistep and time-consuming procedures such as chiral HPLC or diastereomeric resolution. The key to success lies in the face-selective coordination of rhodium to the sterically hindered tetrahydrofluorenyl ligand, giving only one diastereomeric complex.

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.

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.

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.

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 .

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.

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.