Non-palindromic (C^C^D) gold(III) pincer complexes are not accessible by intramolecular oxidative addition of biphenylenes – an experimental and quantum chemical study

We herein report on the synthesis of biphenylenes substituted with a pyridine (N), a phosphine (P) and a carbene (C′) donor as well as a carbene donor with additional pyridine in the lateral position. We describe the synthesis and structures of derived gold(I) complexes, which we tried to use for the synthesis of non-palindromic [(C^C^D)AuIII] pincer complexes by means of an intramolecular oxidative addition of the strained biphenylene ring. However, the anticipated formation of gold(III) complexes failed due to kinetic and thermodynamic reasons, which we extensively investigated by quantum chemical calculations. Furthermore, we shed light on the oxidative addition of biphenylene to two different gold(I) systems reported in the literature. Our comprehensive quantum-chemical analysis is complemented by NMR experiments

Synthetic access to a phosphorescent non-palindromic pincer complex of palladium by a double oxidative addition-comproportionation sequence

A highly luminescent non-palindromic [(C^C^N)Pd] pincer complex forms upon reacting pyridine-substituted 2,2′-diiodo-biphenyl with [Pd(PPh$_{3}$)$_{4}$]. This case study establishes for the first time that the title compound is formed via a double oxidative addition – comproportionation sequence. DFT and TDDFT calculations complement mechanistic and photophysical characterizations

FORMATION OF THE SYSTEM OF IMPLEMENTATION OF THE CRISIS MANAGEMENT MECHANISM BASED ON THE EXAMPLE OF MINING ENTERPRISES

In conditions of economic instability, the problem of implementation of the crisis management mechanism in modern industrial enterprises is of particular importance. The problem of the research is to develop recommendations as a result of the analysis of the financial condition of industrial enterprises of Ukraine in an unstable economy. The paper discusses the features of the implementation of anti-crisis programs in modern mining and processing enterprises with the determination of the share of equity for the difficult conditions of production and economic activity. The aim of the research is to analyze the financial condition of industrial companies and develop recommendations to overcome the crisis. Taking into account the specifics of mining and processing enterprises, in order to overcome the crisis and solve the problems of production for the effective use of raw materials, the paper identified logistics and financial opportunities, made a forecast of the financial condition in the near future and determined the probability of termination of their activities, as well as developed sound recommendations in the context of the implementation of the crisis management mechanism at iron ore plants. The main methods used in the study: analysis, synthesis, comparison, models for assessing the probability of bankruptcy

Synthesis and Characterization of Bis(pyridylimino)isoindolide Alkali Metal Complexes in Three Redox States

Non-innocent ligands (NILs) like bis(pyridylimino)isoindolide (BPI) play crucial roles in coordination chemistry, biosciences, catalysis and material sciences. Investigating the isolated redox states of NILs is inevitable for understanding their redox-activity and fine-tuning the properties of corresponding metal complexes. The limited number of fundamental studies on the coordination behavior and redox chemistry of reduced BPI species is suggested to hamper further applications of the title compounds. This work describes for the first time the isolation of alkali metal complexes of BPI and Me2BPI in three different oxidation states and their characterization by means of NMR or EPR spectroscopy, DFT calculations, and SC-XRD studies. The latter revealed the connection between bond orders in the ligand scaffold and its oxidation state. The paramagnetic compound Me2BPI-K2 was isolated as a coordination copolymer with 18-crown-6, which enabled the characterization of the dianionic BPI radical. Furthermore, the so-far unknown trianionic state of BPI was reported by the isolation of BPI-K3. This divulges an unprecedented bis(amidinato)isoindolide coordination mode

Enhancing the potential of optical coherence tomography in human myopia research

The primary purpose of the work was to assess and enhance OCT-based retinal biomarkers used in human myopia research in the context of advancing OCT technologies. The individual studies provided insights into the repeatability of automated choroidal thickness measurements with spectral-domain and swept-source OCT. Moreover, the work assessed wide- eld topographical choroidal vascularity, retinal and foveal shape in relation to myopia. Finally, novel procedures of retinal shape measurements were compared to peripheral refraction as previously used method for this purpose

Quo Vadis CO2_2 Activation: Catalytic Reduction of CO2_2 to Methanol Using Aluminum and Gallium/Carbon‐based Ambiphiles

We report on so-called “hidden FLPs” (FLP: frustrated Lewis pair) consisting of a phosphorus ylide featuring a group 13 fragment in the ortho position of a phenyl ring scaffold to form five-membered ring structures. Although the formation of the Lewis acid/base adducts was observed in the solid state, most of the title compounds readily react with carbon dioxide to provide stable insertion products. Strikingly, 0.3–3.0 mol% of the reported aluminum and gallium/carbon-based ambiphiles catalyze the reduction of CO$_2$ to methanol with satisfactory high selectivity and yields using pinacol borane as stoichiometric reduction equivalent. Comprehensive computational studies provided valuable mechanistic insights and shed more light on activity differences

Reactivity of a Sterically Unencumbered α-Borylated Phosphorus Ylide towards Small Molecules

The influence of substituents on α‐borylated phosphorus ylides (α‐BCPs) has been investigated in a combined experimental and quantum chemical approach. The synthesis and characterization of Me$_{3}$PC(H)B(iBu)$_{2}$ (1), consisting of small Me substituents on phosphorous and iBu residues on boron, is reported. Compound 1 is accessible through a novel synthetic approach, which has been further elucidated through DFT studies. The reactivity of 1 towards various small molecules was probed and compared with that of a previously published derivative, Ph$_{3}$PC(Me)BEt$_{2}$ (2). Both α‐BCPs react with NH$_{3}$ to undergo heterolytic N−H bond cleavage. Different di‐ and trimeric ring structures were observed in the reaction products of 1 with CO and CO$_{2}$. With PhNCO and PHNCS, the expected insertion products [Me$_{3}$PC(H)(PhNCO)B(iBu)$_{2}$] and [Me$_{3}$PC(H)(PhNCS)B(iBu)$_{2}$], respectively, were isolated

Choroidal biomarkers: a repeatability and topographical comparison of choroidal thickness and choroidal bascularity index in healthy eyes

Purpose: Choroidal thickness (ChT) and choroidal vascularity index (CVI) represent two important metrics in health-, disease-, and myopia-related studies. Wide-field swept-source optical coherence tomography (OCT) provides improved and extended imaging and extraction of choroidal variables. This study characterizes the topography and repeatability of these parameters in healthy eyes.Methods: Swept-source OCT volume scans were obtained on 14 young adult patients on three separate days. ChT and CVI were automatically corrected for image magnification and extracted for different enface regions within an extended ETDRS grid of 10 mm diameter. Topographical distribution, correlation to ocular length, and intersession repeatability of both choroidal parameters were assessed.Results: CVI showed little fluctuation between subfields, unlike ChT, which demonstrated thinning toward the peripheral choroid (coefficients of variation 5.92 vs. 0.89). ChT showed a consistent negative correlation with axial length (ρ = −0.05 to −0.61), although this was only statistically significant in the inner superior subfield (P = 0.02). There was no consistent or significant relationship between CVI and axial length or between CVI and ChT. The repeatability of CVI measurements (3.90%–5.51%) was more consistent between scan regions than ChT measurements (10.37–20.33 µm).Conclusions: CVI values were consistent across the central 10 mm of the retina, while ChT reduced with eccentricity. The repeatability of both parameters is similar to the effect size reported in many studies using the choroid as a biomarker, which should be considered in the interpretation of findings.Translational Relevance: This study provided normative as well as metrological information for the clinical interpretation of ChT and CVI in health and disease