Bidentate N-ligand-assisted gold redox catalysis with hydrogen peroxide.

Gold redox catalysis, which exploits the ability of strong π-acid activation in combination with redox reactions, has emerged as an attractive synthetic method with unique reactivities compared to other transition metals. However, gold redox chemistry bears the challenge to overcome the high redox potential of Au(I)/Au(III) (1.41 V).

Design of a Fixed IF Down-Conversion Double-Balanced Mixer for UHF Band Applications.

This paper presents a new SiGe HBT-based high dynamic range double-balanced down-conversion differential mixer. Operating within the 0.5 GHz to 1.

Gold-Catalysed Intramolecular Reaction of Alkynes with Sulfoximines Acting as N- and O-Transfer Reagents.

Among the nucleophilic oxidants employed in the gold-catalysed oxidation of alkynes, sulphur-based reagents have played a substantial role since the beginning, granting access to the respective gold carbene intermediates. Herein, we describe the first example of the substance class of sulfoximines being used as atom transfer reagents to alkynes in gold catalysis. Based on the transformation of N-(2-alkynylphenyl) sulfoximines to 3H-indol-3-ones, it is demonstrated that the sulfoximine functionality is capable of selectively transferring first its nitrogen moiety to the alkyne, forming the α-imino gold carbene, which is then oxidised by the released sulfoxide moiety in a second step via a pseudo-intramolecular mechanism-a distinctive feature that differentiates this work mechanistically from earlier studies.

Gold-Catalyzed Access to Pyrrolo- and (Aryl)Indolo-Fused Phenazines.

Novel fused phenazines were synthesized through a combination of gold-catalyzed hydroamination and cascade cyclization reactions towards azaacenes. In total, 30 new compounds were synthesized and investigated with respect to their structural and optoelectronic properties. In solution, these targets exhibit strong green to red emission, with quantum yields of up to 60 %.

Gold Meets Selenium: Dual Activation of Selenium-Containing Propargyl Alcohols Towards the Synthesis of 2H-Chromenes and Mechanistic Insights.

Herein, we report the synthesis of seleno-substituted chromenes from selenoalkynes and phenols. In this cascade reaction, the applied gold catalyst not only functions as a π-acid, but also as a Lewis acid, enabling the propargylic substitution in the first step to connect the oxygen carbon bond. Under the optimal reaction condition a total of 26 chromenes were accessible by this modular access.

Selective Coupling of β-(Borylvinyl)silanes by a Gold-Catalyzed Hiyama Reaction-An Easy Way to Diaryl-Substituted Vinyl Boronates.

The use of diaryl-substituted vinyl boronates, a class of chemical building blocks with well-known synthetic utility, is principally limited by the difficulty faced in their preparation. Herein, we present a convenient synthetic strategy based on a gold-catalyzed Hiyama arylation of (Z)-β-(borylvinyl)silanes, which are easily accessible by hydroboration of silylalkynes. By exploiting the highly electronegative nature of the gold(III) intermediate (which is accessed by light-assisted oxidation using aryl diazonium salts), a selective activation of the silyl group in the presence of the boron moiety is achieved.

mSLAb - An open-source masked stereolithography (mSLA) bioprinter.

3D bioprinting is a tissue engineering approach using additive manufacturing to fabricate tissue equivalents for regenerative medicine or medical drug testing. For this purpose, biomaterials that provide the essential microenvironment to support the viability of cells integrated directly or seeded after printing are processed into three-dimensional (3D) structures. Compared to extrusion-based 3D printing, which is most commonly used in bioprinting, stereolithography (SLA) offers a higher printing resolution and faster processing speeds with a wide range of cell-friendly materials such as gelatin- or collagen-based hydrogels and SLA is, therefore, well suited to generate 3D tissue constructs.

Synthesis of 2,3-Dihydrobenzofurans via a Photochemical Gold-Mediated Atom Transfer Radical Addition Reaction.

A light-mediated cyclization reaction initiated by an atom transfer radical addition (ATRA) of haloalkanes onto alkenes was exploited for the synthesis of functionalized dihydrobenzofurans. Initial investigation indicated that the dimeric gold catalyst [Au(μ-dppm)Cl] can effectively be used for intermolecular ATRA reactions. Further, the reactivity was applied in a cascade-like cyclization for the preparation of dihydrobenzofuran derivatives.

Easy Access to Functionalized Indolines and Tetrahydroquinolines via a Photochemical Cascade Cyclization Reaction.

Herein, the development of a light-mediated synthesis of functionalized indolines and tetrahydroquinolines is reported. These structural motifs are considered as highly valuable targets, attributed to their widespread occurrence in pharmaceuticals and natural products. The gold-mediated approach offers a direct route to functionalized indolines in yields of up to 81% under mild photochemical conditions.

Gold(I)-Catalyzed Intramolecular 7-endo-dig Cyclization of Triene-Yne Systems: New Access towards Azulenothiophenes.

We report the direct synthesis of new azulene derivatives through gold-catalyzed cyclization reactions. A five-membered ring as backbone in the applied triene-yne substrates turned out to be crucial to induce the 7-endo-dig cyclization mode necessary to trigger azulene formation. The obtained targets are of high interest due to their potential applications in different fields, like organic materials, medicine or cosmetics.

Synthesis and structural properties of -diselenopyrazines.

Recently, dithienopyrazines have emerged as promising building blocks in the field of materials science, showcasing their potential as hole-transport materials in organic electronic devices. Herein, we report the synthesis of its heavier analogues, the diselenopyrazines, along with an analysis of their optoelectronic and structural properties. In the acquired crystal structures, interesting molecular packing motifs suitable for potential device fabrication were observed.

Cascade Reactions of Aryl-Substituted Terminal Alkynes Involving in Situ-Generated α-Imino Gold Carbenes.

An efficient, highly selective and divergent synthetic method to construct 2-substituted indoles and aryl-annulated carbazoles via the intermolecular generation of α-imino gold carbenes from terminal alkynes or diynes in combination with sulfilimines is disclosed. Importantly, the tandem reaction is proposed to proceed through an intermolecular gold carbene generation/C-H annulation followed by the activation of a second alkyne leading to 6-endo-dig cyclization, which is significantly different from previous dual activation or 1,6-carbene shift approaches for diyne systems. In the case of ortho-alkynylaniline as starting material, an unexpected regioselective formation of the indole moiety via the intermolecular path, instead of intramolecular hydroamination was discovered.

[Stress and suffering from tinnitus-a psychosomatic approach].

The development and processing of tinnitus is often associated with stress. There are many publications on this subject that have investigated possible connections between stress perception and tinnitus symptoms using different concepts and different test inventories. In this review, we present the development of Selye's concept of stress using the transactional stress model of Lazarus and its transfer to patients suffering from tinnitus.

Light-Induced Metal-Free Generation of Cyanocarbenes from Alkynyl Triazenes for the Synthesis of Nitrile Derivatives.

The chemistry of alkynyl triazenes is an emerging field for organic chemists and especially acid-induced nucleophilic functionalizations, either directly, or after a prior reaction towards aromatic triazenes under extrusion of nitrogen, paved the way for fruitful strategies. In contrast, the chemical behavior of alkynyl triazenes upon irradiation with light is still unknown. Herein we present the first photoactivation of alkynyl triazenes that triggers an uncommon reactivity pattern involving the cleavage of the N1-N2 bond of the triazene moiety resulting in a unique approach to cyanocarbenes from a readily available, stable, and insensitive precursor.

Gold(I)-Mediated Cyclizations of Triene-Yne Systems: An Easy Access to Cyclopenta-Fused Anthracenes.

The direct synthesis of cyclopenta-fused anthracenes (CP-anthracenes) through a gold(I)-catalyzed cyclization reaction of easily available triene-yne systems bearing a benzofulvene substructure, is reported. The targets are of great interest due to the potential use as organic materials and the preparation of these compounds is gaining huge importance. The applied starting materials are readily available through a three-step synthesis, which further contributes to the advantages of this route.

Gold-Catalyzed Formal [4+2] Cycloaddition as Access to Antitumor-Active Spirocyclic Oxindoles from Alkynes and Isatin-Derived Ketimines.

Due to its excellent bioactivity profile, which is increasingly utilized in pharmaceutical and synthetic chemistry, spirooxindole is an important core scaffold. We herein describe an efficient method for the construction of highly functionalized new spirooxindolocarbamates via a gold-catalyzed cycloaddition reaction of terminal alkynes or ynamides with isatin-derived ketimines. This protocol has a good functional group compatibility, uses readily available starting materials, mild reaction conditions, low catalyst loadings and no additives.

Gold-Catalyzed [3,3]-Sigmatropic Rearrangement of -Alkynyl-,-diarylsulfilimines.

Highly functionalized 5-pyrrolo[2,3-]pyrazine cores, carrying a diaryl sulfide moiety at the C-7 position, were obtained from a gold-catalyzed reaction using easily accessible -alkynyl-substituted ,-diarylsulfilimines as intramolecular nitrene transfer reagents for the first time. The reaction proceeds under mild conditions, providing excellent yields while tolerating a large variety of different substitution patterns. We provide experimental evidence for an intramolecular reaction mechanism, likely including an unprecedented gold-catalyzed amino sulfonium [3,3]-sigmatropic rearrangement.

Gold-Catalyzed Regio- and Stereoselective α-Acyloxy-β-Alkynylation of Ynol Ethers.

Enol esters and conjugated enynes are valuable structural motifs for synthetic chemistry and material sciences. Herein, the synthesis of tetra-substituted enol ester 2-iodobenzoate derivatives was achieved in good yields at room temperature through a gold-catalyzed acyloxyalkynylation of sensitive ynol ethers with ethynylbenziodoxolones (EBXs), the latter acting as bifunctional reactants. The conversion is highly regioselective with a broad substrate scope.

Illness Beliefs, Treatment Beliefs, and Fulfilled Treatment Expectations in Psychosomatic Rehabilitation: Associations with Patient Satisfaction.

Purpose: Patients' illness and treatment beliefs have been shown to predict health outcomes in many health care settings. However, information about their impact on patient satisfaction is scarce. The aim of this study was to investigate illness- and rehabilitation-related treatment beliefs and met rehabilitation-related treatment expectations and their relationship with patient satisfaction in psychosomatic rehabilitation.

Psychometric properties of the rehabilitation treatment beliefs questionnaire for psychosomatic rehabilitation.

Purpose: Treatment beliefs play a crucial role for patient satisfaction and the treatment outcome in psychosomatic rehabilitation. The aim of this study was the development and the psychometric evaluation of an indication-specific questionnaire of beliefs about psychosomatic rehabilitation.

Materials And Methods: The study was conducted at a psychosomatic rehabilitation clinic.

Three-Dimensional Metal-Insulator-Metal Decoupling Capacitors with Optimized ZrO ALD Properties for Improved Electrical and Reliability Parameters.

Embedded three-dimensional (3-D) metal-insulator-metal (MIM) decoupling capacitors with high-κ dielectric films of high capacitance and long-life time are increasingly needed on integrated chips. Towards achieving better electrical performance, there is a need for investigation into the influence of the variation in atomic layer deposition (ALD) parameters used for thin high-κ dielectric films (10 nm) made of AlO-doped ZrO. This variation should always be related to the structural uniformity, the electrical characteristics, and the electrical reliability of the capacitors.

Synthesis of Amide Enol 2-Iodobenzoates by the Regio- and Stereoselective Gold-Catalyzed Acyloxyalkynylation of Ynamides with Hypervalent Iodine Reagents.

Multisubstituted alkenes are accessible by a gold-catalyzed acyloxyalkynylation of ynamides with ethynylbenziodoxolones (EBXs) with perfect atom-economy. The EBX reagents transfer both the carboxylate as well as the alkynyl entity. Overall, this cascade comprises the in situ generation of an alkynyl gold(III) species, a stereoselective C(sp)-C(sp) bond formation, and a C-O coupling at the alkynyl position of the ynamides.