Mononuclear chelates of Cr(III), Mn(II), Fe(III), Ni(II), Cu(II), Zn(II) and Cd(II) resulted from new tridentate Schiff base ligand, 4-((1-(5-acetyl-2,4-dihydroxyphenyl)ethylidene)amino)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one, were synthesized. Metal to ligand ratio was found to be1 : 1, which was revealed via elemental analysis and characterized via various spectroscopic tools. IR has point out that the coordination of the ligand towards the metal ions was carried out via NOO donor atoms. UV-Vis, H NMR spectral data, molar conductivity measurements, BET surface area, melting points and theoretically through density function theory were used such as characterizing techniques in supporting further interpretation of the complexes structures. The complexes were octahedral except Cu(II) and Ni(II) complexes were tetrahedral as suggested from the magnetic moment measurement. The complexes were found to have surface area, pore volume and particle radius of 23-176 m g, 0.02-0.33 cc/g and 8.71-4.32 nm, respectively, as pointed out from BET measurement. Schiff base ligand and metal complexes were tested to estimate their antimicrobial activity opposed to Gram-negative and Gram-positive bacterial and fungal organisms. MOE 2008 was used headed for screen potential drugs with molecular docking by the protein sites of new coronavirus and the study was constructed to molecular docking without validation through MD simulations.

Nature uses control of the secondary coordination sphere to facilitate an astounding variety of transformations. Similarly, synthetic chemists have found metal-ligand cooperativity to be a powerful strategy for designing complexes that can mediate challenging reactivity. In particular, this strategy has been used to facilitate two electron reactions with first row transition metals that more typically engage in one electron redox processes. While NNN pincer ligands feature prominently in this area, examples which can potentially engage in both proton and electron transfer are less common. Dihydrazonopyrrole (DHP) ligands have been isolated in a variety of redox and protonation states when complexed to Ni. However, the redox-state of this ligand scaffold is less obvious when complexed to metal centers with more accessible redox couples. Here, we synthesize a new series of Fe-DHP complexes in two distinct oxidation states. Detailed characterization supports that the redox-chemistry in this set is still primarily ligand based. Finally, these complexes exist as 5-coordinate species with an open coordination site offering the possibility of enhanced reactivity.

In the present work we have prepared and fully characterized several Fe(0) complexes of the type [Fe(PNP)(CO)] treating Fe(II) complexes [Fe(PNP)(Cl)] with KC in the presence of carbon monoxide. While complexes [Fe(PNP-Pr)(CO)], [Fe(PNP-Pr)(CO)] adopt a trigonal bipyramidal geometry, the bulkier and more electron rich [Fe(PNP-Bu)(CO)] is closer to a square pyramidal geometry. Mössbauer spectra showed isomer shifts very close to 0 and similar to those reported for Fe(I) systems. Quadrupole splitting values range between 2.2 and 2.7 mm s both in experiments and DFT calculations, while those of Fe(I) complexes are much smaller (∼0.6 mm s).

The synthesis and characterization of two heterobimetallic complexes [K([18]crown-6){(η-CH)Fe(μ-η:η-P)Ga(nacnac)}] () (CH = anthracene) and [K(dme){(η-CH)Co(μ-η:η-P)Ga(nacnac)}] () with strongly reduced P units is reported. Compounds and are prepared by reaction of the gallium(III) complex [(nacnac)Ga(η-P)] (nacnac = CH[CMeN(2,6-PrCH)]) with bis(anthracene)ferrate(1-) and -cobaltate(1-) salts. The molecular structures of and were determined by X-ray crystallography and feature a P chain which binds to the transition metal atom via all four P atoms and to the gallium atom via the terminal P atoms. Multinuclear NMR studies on suggest that the molecular structure is preserved in solution.

Terminal, electrophilic phosphinidene complexes (M=PR) are attractive platforms for PR-transfer to organic substrates. In contrast to aryl- or alkylphosphinidene complexes terminal chlorophosphinidenes (M=PCl) have only been proposed as transient intermediates but isolable example remain elusive. Here we present the transfer of PCl from chloro-substituted dibenzo-7λ-phosphanorbornadiene to a square-planar osmium(II) PNP pincer complex to give the first isolable, terminal chlorophosphinidene complex with remarkable thermal stability. Os=P bonding was examined computationally giving rise to highly covalent {Os=PCl} double bonding.

The preparation and isolation of the metalated ylides [CyPCSOTol]M ( ) (with M = Li, Na, K) are reported. In contrast to its triphenylphosphonium analogue the synthesis of revealed to be less straight forward. Synthetic routes to the phosphonium salt precursor - via different methods revealed to be unsuccessful or low-yielding. However, nucleophilic attack of the ylide CyP = CH at toluenesulfonyl fluoride under basic conditions proved to be a high-yielding method directly leading to the ylide . Metalation to the yldiides was finally achieved with strong bases such as BuLi, NaNH, or BnK. In the solid state, the lithium compound forms a tetrameric structure consisting of a (C-S-O-Li) macrocycle, which incorporates an additional molecule of lithium iodide. The potassium compound forms a -symmetric structure with a (KO) octahedral prism as central structural motif. Upon deprotonation the P-C-S linkage undergoes a remarkable contraction typical for metalated ylides.

In a 2:2 reaction with silver(I) chloride or bromide, 1,5-bis(1-phospholano)pentane () afforded frame-like macrocyclic structures, with intra- (, Cl) or intermolecular (, Br) halido bridges. In contrast, 1,7-bis(1-phospholano)heptane () formed coordination polymers (Cl) and (Br) with bridging bis-phospholane and halido ligands. A unique paddle wheel-type metallacryptand structure was obtained from and silver(I) bromide in a 2:3 reaction (M:L). All complexes were fully characterized by NMR, IR spectroscopy, mass spectrometry, and X-ray crystallography.

The element lithium has been discovered 200 years ago. Due to its unique properties it has emerged to play a vital role in industry, esp. for energy storage, and lithium-based products and processes support sustainable technological developments. In addition to the many uses of lithium in its inorganic forms, lithium has a rich organometallic chemistry. The development of organometallic chemistry has been hindered by synthetic problems from the start. When developed the basic principles to handle and synthesize air- and moisture-sensitive compounds, the road was open to further developments. After more information was available about the stability and solubility of such compounds, they started to play an essential role in other fields of chemistry as alkyl or aryl transfer reagents.

An improved synthesis using microwave heating affords (CHPO(OCH)) in excellent isolated yield (95 %). The ligand properties of this bisphosphonateester were explored towards hard metal centers ( = Ca, UO) and ( = La, Ce, Sm, Eu) resulting in coordination polymers, for which the reduction of ionic size of the central metal atom resulted in lower-dimensional structural motifs as opposed to higher dimensional networks obtained for the larger ions. All coordination polymers were characterized by single-crystal X-ray diffraction, IR spectroscopy, and combustion analysis. The ligand was furthermore characterized with multinuclear NMR spectroscopy.

Power electronics belongs to the future key technologies in order to increase system efficiency as well as performance in automotive and energy saving applications. Silicon is the major material for electronic switches since decades. Advanced fabrication processes and sophisticated electronic device designs have optimized the silicon electronic device performance almost to their theoretical limit. Therefore, to increase the system performance, new materials that exhibit physical and chemical properties beyond silicon need to be explored. A number of wide bandgap semiconductors like silicon carbide, gallium nitride, gallium oxide, and diamond exhibit outstanding characteristics that may pave the way to new performance levels. The review will introduce these materials by (i) highlighting their properties, (ii) introducing the challenges in materials growth, and (iii) outlining limits that need innovation steps in materials processing to outperform current technologies.

The structure of one of the first permanently porous metal phosphonates, MIL-91(Al) was re-determined using high resolution synchrotron powder X-ray diffraction data. The new model is in a lower symmetry space group, with no disordered ligands in the structure, whilst remaining otherwise consistent with the reported compound. New milder synthetic conditions were also developed.

We examine the life, work, and legacy of Clara Haber, nee Immerwahr, who became the first woman to earn a doctorate from the University of Breslau, in 1900. In 1901 she married the chemist Fritz Haber. With no employment available for female scientists, Clara freelanced as an instructor in the continued education of women, mainly housewives, while struggling not to become a housewife herself. Her duties as a designated head of a posh household hardly brought fulfillment to her life. The outbreak of WWI further exacerbated the situation, as Fritz Haber applied himself in extraordinary ways to aid the German war effort. The night that he celebrated the "success" of the first chlorine cloud attack, Clara committed suicide. We found little evidence to support claims that Clara was an outspoken pacifist who took her life because of her disapproval of Fritz Haber's involvement in chemical warfare. We conclude by examining "the myth of Clara Immerwahr" that took root in the 1990s from the perspective offered by the available scholarly sources, including some untapped ones.

Nano-grained CoSb was prepared by melt-spinning and subsequent spark plasma sintering. The phonon thermal conductivity of skutterudites is known to be sensitive to the kind and the amount of guest atoms. Thus, unfilled CoSb can serve as model compound to study the impact of a nanostructure on the thermoelectric properties, especially the phonon thermal conductivity. Therefore, a series of materials was prepared differing only by the cooling speed during the quenching procedure. In contrast to clathrates, the microstructure of meltspun CoSb was found to be sensitive to the cooling speed. Although the phonon thermal conductivity, studied by means of Flash and 3 measurements, was found to be correlated with the grain size, the bulk density of the sintered materials had an even stronger impact. Interestingly, the reduced bulk density did not result in an increased electrical resistivity. The influence of Sb and CoSb as foreign phase on the electronic properties of CoSb was revealed by a multi-band Hall effect analysis. While CoSb increases the charge carrier density, the influence of the highly mobile charge carriers introduced by elemental Sb on the thermoelectric properties of the composite offer an interesting perspective for the preparation of efficient thermoelectric composite materials.

A molybdenum L-edge X-ray absorption spectroscopy (XAS) study is presented for native and oxidized MoFe protein of nitrogenase as well as Mo-Fe model compounds. Recently collected data on MoFe protein (in oxidized and reduced forms) is compared to previously published Mo XAS data on the isolated FeMo cofactor in NMF solution and put in context of the recent Mo K-edge XAS study, which showed a Mo assignment for the molybdenum atom in FeMoco. The L-edge data are interpreted within a simple ligand-field model, from which a time-dependent density functional theory (TDDFT) approach is proposed as a way to provide further insights into the analysis of the molybdenum L-edges. The calculated results reproduce well the relative spectral trends that are observed experimentally. Ultimately, these results give further support for the Mo assignment in protein-bound FeMoco, as well as isolated FeMoco.

An overview is given on the ways databases can be employed to aid in the prediction of chemical compounds, in particular inorganic crystalline compounds. Methods currently employed and possible future approaches are discussed.

An ionic liquid assisted strategy for the synthesis of zeolitic material is reported. This strategy is a solid state synthetic method and the ionic liquid is employed as structure directing agent. A TON-type zeolite, which contains one-dimensional 10-member-ring, is successfully synthesized with the assistance of the ionic liquid, 1-ethyl-3-methylimidazolium bromide. This finding improves our understanding about the challenge of ionothermally synthesizing siliceous and aluminosilicate zeolites.

Dynamic and static electron densities (EDs) based on the independent spherical atom model (IAM) and multipole (MP) models of crambin were successfully computed, holding no series-termination effects. The densities are compared to EDs of small biological molecules at diverse temperatures. It is outlined that proteins exhibit an intrinsic flexibility, present as frozen disorder at 100 K, in contrast to small molecules. The flexibility of the proteins is reflected by atomic displacement parameters (B-factors), which are considerably larger than for small molecules at 298 K. Thus, an optimal deconvolution of deformation density and thermal motion is not guaranteed, which prevents a free refinement of MP parameters but allows an application of transferable, fixed MP parameters. The analysis of the topological properties, such as the density at bond critical points (BCPs) and the Laplacian, reveals systematic differences between static and dynamic EDs. Zero-point-vibrations, yet present in dynamic EDs at low temperature, affect but marginally the EDs of small molecules. The zero-point-vibrations cause a smearing of the ED, which becomes more pronounced with increasing temperature. Topological properties, primarily the Laplacian, of covalent bonds appear to be more sensitive to effects by temperature and the polarity of the bonds. However, dynamic EDs at ca. 20 K based on MP models provide a good characterization of chemical bonding. Both the density at BCPs and the Laplacian of hydrogen bonds constitute similar values from static and dynamic EDs for all studied temperatures. Deformation densities demonstrate the necessity of the employment of MP parameters in order to comprise the nature of covalent bonds. The character of hydrogen bonds can be roughly pictured by IAM, whereas MP parameters are recommended for a classification of hydrogen bonds beyond a solely interpretation of topological properties.

This report describes the dimerisation of glutathione, and by extension, other cysteine-containing peptides or protein fragments, with a 5, 5'-disubstituted-2, 2'-bipyridine or 6, 6"-disubstituted-2, 2':6',2"-terpyridine unit. The resulting - and - were investigated as potential metal ion dependent switches in aqueous solution, and were found to predominantly adopt the conformation at physiological pH. Metal complexation with Cu and Zn at this pH has been studied by UV/Vis, CD, NMR and ion-mobility mass spectrometry. Zn titrations are consistent with the formation of a 1:1 Zn:- complex at pH 7.4, but - was shown to form both 1:1 and 1:2 complexes with the former being predominant under dilute micromolar conditions. Formation constants for the resulting 1:1 complexes were determined to be log 6.86 (- ) and 6.22 (- ), consistent with a higher affinity for the unconstrained bipyridine, compared to the strained terpyridine. Cu coordination involves the initial formation of 1:1 complexes, followed by 1.5Cu:1- and 2Cu:1- complexes at micromolar concentrations. Binding constants for formation of the 1:1 complexes (log 12.5 (- ); 8.04 and 7.14 (- )) indicate a higher affinity for Cu than Zn. Finally, ion-mobility MS studies detected the free ligands in their protonated form, and were consistent with the formation of two different Cu adducts with different conformations in the gas-phase. We illustrate that the bipyridine and terpyridine dimerisation units can behave like conformational switches in response to Cu/Zn complexation, and propose that in future these can be employed in synthetic biology with larger peptide or protein fragments, to control large scale folding and related biological function.

A sulfide-bridged diiron(II) complex bearing a -NH (hydrazine) ligand has been prepared by reaction of LFe(-S)FeL (; L = sterically encumbered βdiketiminate ligand) with 2 molar equivalents of NH. The metastable diiron(II) hydrazine complex LFe(-S)(H N-NH)Fe () is formed, as shown by crystallography, and NMR, vibrational, and electronic absorption spectroscopies. Compound has been crystallographically characterized as its DBU (1,8-diazabicyclo[5.4.0]undec-7$ene) adduct, which exhibits weak N-H···DBU hydrogen bonding. The synthetic process evolves roughly 2 equivalents of NH. The -NH bridge in may be relevant to the structure and function of intermediates on the FeMoco of nitrogenase.

CeBO was synthesized under conditions of 2.6 GPa and 750 °C in a Walker-type multianvil apparatus. The crystal structure was determined on the basis of single-crystal X-ray diffraction data, collected at room temperature, revealing that CeBO is isotypic to LaBO. CeBO crystallizes monoclinically with four formula units in the space group 2/ (No. 15) and the lattice parameters = 1117.8(2), = 640.9(2), = 2531.7(5) pm, and = 100.2(1)°. The three-dimensional boron-oxygen framework consists of [BO] tetrahedra and trigonal-planar [BO] groups. The structure contains two crystallographically different cerium ions. Furthermore, Raman spectroscopy was performed on single crystals of CeBO.

An alternative synthesis of -monoacetylenic phosphaalkenes -Mes*P=C(Me)(C≡CR) (Mes* = 2, 4, 6-BuPh, R = Ph, SiMe) from -bromophosphaalkenes -Mes*P=C(Me)Br using standard Sonogashira coupling conditions is described. Crystallographic studies confirm - isomerization of the P=C double bond during Pd-catalyzed cross coupling, leading exclusively to -acetylenic phosphaalkenes. Crystallographic studies of all synthesized compounds reveal the extend of π-conjugation over the acetylene and P=C π-systems.