A Reduced 2Fe2S Cluster Probe of Sulfur–Hydrogen versus Sulfur–Gold Interactions

The Ph₃PAu⁺ cation, renowned as an isolobal analogue of H⁺, was found to serve as a proton surrogate and form a stable Au₂Fe₂ complex, [(μ‐SAuPPh₃)₂{Fe(CO)₃}₂], analogous to the highly reactive dihydrosulfide [(μ‐SH)₂{Fe(CO)₃}₂]. Solid‐state X‐ray diffraction analysis found the two SAuPPh₃ and SH bridges in anti configurations. VT NMR studies, supported by DFT computations, confirmed substantial barriers of approximately 25 kcal mol⁻¹ to intramolecular interconversion between the three stereoisomers of [(μ‐SH)₂{Fe(CO)₃}₂]. In contrast, the largely dative S Au bond in μ‐SAuPPh₃ facilitates inversion at S and accounts for the facile equilibration of the SAuPPh₃ units, with an energy barrier half that of the SH analogue. The reactivity of the gold‐protected sulfur atoms of [(μ‐SAuPPh₃)₂{Fe(CO)₃}₂] was accessed by release of the gold ligand with a strong acid to generate the [(μ‐SH)₂{Fe(CO)₃}₂] precursor of the [FeFe]H₂ase‐active‐site biomimetic [(μ₂‐SCH₂(NR)CH₂S){Fe(CO)₃}₂].     

Anticancer anilinoacridines. A process synthesis of the disubstituted amsacrine analog CI-921

An improved process for the synthesis of bulk quantities of the clinical amsacrine analog CI-921 is reported. Described also are detailed analytical and spectroscopic data for this agent.     

Benzotliiazolinc derivatives. IV. Comment on the. Mechanism of reaction of 2-l5enzolhiazolinetliione willi ethylene oxide in acetic acid

Treatment of 2,3-dihydrothiazolo|2,3-b Iben|othiazolium bromide with sodium acetate in acetic acid gave predominantly 3-(2-accloxyethyl)-2-benothiazolinelhiorie and the minor product 3-(2-acetyllhioelhyl)-2-benzothiazolinone. The mechanistic implications of this and previous results are discussed in terms of the reaction of 2-benzothiazolitielhione and its derivatives with ethylene oxide in acetic acid.     

Comparisons of zinc with cadmium in N2S2 coordination and as S-bonded adducts to tungsten carbonyls

The synthesis and characterization of bis-mercaptoethanediazaheptane cadmium(II) is reported and compared to the analogous zinc complex. Of significance is the dimeric form of the [Zn(N(2)S(2))](2) complex achieves penta-coordination about zinc through a bridging thiolate whereas cadmium engages two thiolate as S-bridges resulting in hexa-coordination about cadmium within a coordination polymer whose X-ray crystal structure is reported here. In the presence of W(CO)(5), this polymer breaks up, generating dimeric [Cd(N(2)S(2))](2) with two W(CO)(5) units appended to the terminal thiolates, a feat that is not observed for the zinc dimer analogue. The greater thiophilicity of cadmium over zinc is noted in several features of these complexes.     

Spectroscopic analysis of packaging concepts for high-power diode laser bars

Double-side cooled high-power diode laser bars packaged by different techniques on different types of passive heat sinks are analyzed in terms of packaging-induced strain. Reference data from standard devices being single-side cooled only and packaged by conventional soft and hard soldering are also presented. Thermal profiling across the devices complements the results. The most suitable packaging architecture and technique for double-side cooled bars is identified. Measurements of the laser emission near field and electroluminescence pattern provide direct reference to the functionality of the devices. Furthermore, a type of cross calibration of the methods used for strain analysis is made, since all techniques are applied to the same set of bars. This involves micro photoluminescence, micro Raman, and degree-of-polarization electroluminescence spectroscopy.     

A new short synthesis of 5,6-dimethylxanthenone-4-acetic acid (ASA404, DMXAA)

A new short synthesis of 5,6-dimethylxanthenone-4-acetic acid (ASA404) is developed. The key steps of the synthesis are dibromination of 3,4-dimethylbenzoic acid, followed by regioselective coupling with 2-hydroxyphenylacetic acid and subsequent cyclodehydration.     

Effectiveness of Bioactive Compound as Antibacterial and Anti-Quorum Sensing Agent from Myrmecodia pendans: An In Silico Study

Background: antibiotic resistance encourages the development of new therapies, or the discovery of novel antibacterial agents. Previous research revealed that Myrmecodia pendans (Sarang Semut) contain potential antibacterial agents. However, specific proteins inhibited by them have not yet been identified as either proteins targeted by antibiotics or proteins that have a role in the quorum-sensing system. This study aims to investigate and predict the action mode of antibacterial compounds with specific proteins by following the molecular docking approach. Methods: butein (1), biflavonoid (2), 3″-methoxyepicatechin-3-O-epicatechin (3), 2-dodecyl-4-hydroxylbenzaldehyde (4), 2-dodecyl-4-hydroxylbenzaldehyde (5), pomolic acid (6), betulin (7), and sitosterol-(6′-O-tridecanoil)-3-O-β-D-glucopyranoside (8) from M. pendans act as the ligand. Antibiotics or substrates in each protein were used as a positive control. To screen the bioactivity of compounds, ligands were analyzed by Prediction of Activity Spectra for Substances (PASS) program. They were docked with 12 proteins by AutoDock Vina in the PyRx 0.8 software application. Those proteins are penicillin-binding protein (PBP), MurB, Sortase A (SrtA), deoxyribonucleic acid (DNA) gyrase, ribonucleic acid (RNA) polymerase, ribosomal protein, Cytolysin M (ClyM), FsrB, gelatinase binding-activating pheromone (GBAP), and PgrX retrieved from UniProt. The docking results were analyzed by the ProteinsPlus and Discovery Studio software applications. Results: most compounds have Pa value over 0.5 against proteins in the cell wall. In nearly all proteins, biflavonoid (2) has the strongest binding affinity. However, compound 2 binds only three residues, so that 2 is the non-competitive inhibitor. Conclusion: compound 2 can be a lead compound for an antibacterial agent in each pathway.     

Some isomorphically polyhedral orlicz sequence spaces

A Banach space is polyhedral if the unit ball of each of its finite dimensional subspaces is a polyhedron. It is known that a polyhedral Banach space has a separable dual and isc ₀-saturated, i.e., each closed infinite dimensional subspace contains an isomorph ofc ₀. In this paper, we show that the Orlicz sequence spaceh _M is isomorphic to a polyhedral Banach space if lim _t→0 M(Kt)/M(t)=∞ for someK<∞. We also construct an Orlicz sequence spaceh _M which isc ₀-saturated, but which is not isomorphic to any polyhedral Banach space. This shows that beingc ₀-saturated and having a separable dual are not sufficient for a Banach space to be isomorphic to a polyhedral Banach space.