High-spin iron(II) complexes with mono-phosphorylated 2,6-diaminopyridine ligands

Several new monophosphorylated 2,6-diaminopyridine ligands bearing PiPr2 and PtBu2 units (PNNH2-iPr, PNNH2-tBu, PNNHMe-iPr, and PNNHEt-iPr) are prepared by treatment of the respective 2,6-diaminopyridines with the chlorophosphines PiPr2Cl and PtBu2Cl in the presence of a base. Treatment of anhydrous FeCl2 with 1 equiv of these afforded the tetracoordinated coordinatively unsaturated 14e− complexes [Fe(κ2P,N-PNNH2-iPr)Cl2] and [Fe(κ2P,N-PNNH2-tBu)Cl2], while with PNNHMe-iPr and PNNHEt-iPr a phosphine transfer reaction of a second PN ligand took place to yield the known PNP pincer complexes [Fe(κ3P,N,P-PNPMe-iPr)Cl2] and [Fe(κ3P,N,P-PNPEt-iPr)Cl2]. The four-coordinate complexes [Fe(κ2P,N-PNNH2-iPr)Cl2] and [Fe(κ2P,N-PNNH2-tBu)Cl2] did not react with CO and the formation of iron PNC pincer complexes was not observed. The reason for the reluctance to add CO was investigated in detail by DFT calculations

Directing Intrinsic Chirality in Gold Nanoclusters: Preferential Formation of Stable Enantiopure Clusters in High Yield and Experimentally Unveiling the “Super” Chirality of Au144_{144}

Chiral gold nanoclusters offer significant potential for exploring chirality at a fundamental level and for exploiting their applications in sensing and catalysis. However, their widespread use is impeded by low yields in synthesis, tedious separation procedures of their enantiomeric forms, and limited thermal stability. In this study, we investigated the direct synthesis of enantiopure chiral nanoclusters using the chiral ligand 2-MeBuSH in the fabrication of Au$_{25}$, Au$_{38}$, and Au$_{144}$ nanoclusters. Notably, this approach leads to the unexpected formation of intrinsically chiral clusters with high yields for chiral Au$_{38}$ and Au$_{144}$ nanoclusters. Experimental evaluation of chiral activity by circular dichroism (CD) spectroscopy corroborates previous theoretical calculations, highlighting the stronger CD signal exhibited by Au$_{144}$ compared to Au$_{38}$ or Au$_{25}$. Furthermore, the formation of a single enantiomeric form is experimentally confirmed by comparing it with intrinsically chiral Au$_{38}$(2-PET)$_{24}$ (2-PET: 2-phenylethanethiol) and is supported theoretically for both Au$_{38}$ and Au$_{144}$. Moreover, the prepared chiral clusters show stability against diastereoisomerization, up to temperatures of 80°C. Thus, our findings not only demonstrate the selective preparation of enantiopure, intrinsically chiral, and highly stable thiolate-protected Au nanoclusters through careful ligand design but also support the predicted “super” chirality in the Au$_{144}$ cluster, encompassing hierarchical chirality in ligands, staple configuration, and core structure

Advances in structure elucidation of small molecules using mass spectrometry

The structural elucidation of small molecules using mass spectrometry plays an important role in modern life sciences and bioanalytical approaches. This review covers different soft and hard ionization techniques and figures of merit for modern mass spectrometers, such as mass resolving power, mass accuracy, isotopic abundance accuracy, accurate mass multiple-stage MS(n) capability, as well as hybrid mass spectrometric and orthogonal chromatographic approaches. The latter part discusses mass spectral data handling strategies, which includes background and noise subtraction, adduct formation and detection, charge state determination, accurate mass measurements, elemental composition determinations, and complex data-dependent setups with ion maps and ion trees. The importance of mass spectral library search algorithms for tandem mass spectra and multiple-stage MS(n) mass spectra as well as mass spectral tree libraries that combine multiple-stage mass spectra are outlined. The successive chapter discusses mass spectral fragmentation pathways, biotransformation reactions and drug metabolism studies, the mass spectral simulation and generation of in silico mass spectra, expert systems for mass spectral interpretation, and the use of computational chemistry to explain gas-phase phenomena. A single chapter discusses data handling for hyphenated approaches including mass spectral deconvolution for clean mass spectra, cheminformatics approaches and structure retention relationships, and retention index predictions for gas and liquid chromatography. The last section reviews the current state of electronic data sharing of mass spectra and discusses the importance of software development for the advancement of structure elucidation of small molecules

Légúti idegentestek előfordulásának gyakorisága gyermekkorban

Gyermekkori légúti idegentestek viszonylag gyakori balesetnek számítanak. A balesetek nagy része megelőzhető lenne megfelelő táplálkozással, szülők megfelelő felvilágosításával. A légúti idegentest gyanúval érkező gyermek ellátása során az ápolónak kiemelkedő szerepe vanBSc/BAápolás és betegellátás – ápolómagyarlevelez