Intramuscular myxoma of the biceps brachii muscle:a case report

Intramuscular myxoma (IM) is a rare benign tumour. It may occur at any age but most commonly occurs among older women. The preoperative diagnosis of IM is complicated. The diagnosis can only be definitively established by histopathological examination. The treatment of choice is radical surgical excision. We report a case of a 41-year-old woman with an IM of the biceps brachii muscle

Bottleable neutral analogues of [B2H5]- as versatile and strongly binding eta2 donor ligands

Herein we report the discovery that two bottleable, neutral, base-stabilized diborane(5) compounds are able to bind strongly to a number of copper(I) complexes exclusively through their B-B bond. The resulting complexes represent the first known complexes containing unsupported, neutral σB-B diborane ligands. Single-crystal X-ray analyses of these complexes show that the X-Cu moiety (X = Cl, OTf, C6F5) lies opposite the bridging hydrogen of the diborane and is near perpendicular to the B-B bond, interacting almost equally with both boron atoms and causing a B-B bond elongation. DFT studies show that σ donation from and π backdonation to the pseudo-π-like B-B bond account for their formation. Astoundingly, these copper σB-B-complexes are inert to ligand exchange with pyridine under either heating or photoirradiation

Monomeric 16-Electron π-Diborene Complexes of Zn(II) and Cd(II)

Despite the prevalence of stable π-complexes of most d10 metals, such as Cu(I) and Ni(0), with ethylene and other olefins, complexation of d10 Zn(II) to simple olefins is too weak to form isolable complexes due to the metal ion's limited capacity for π-backdonation. By employing more strongly donating π-ligands, namely neutral diborenes with a high-lying π(B=B) orbital, monomeric 16-electron M(II)-diborene (M = Zn, Cd) π-complexes were synthesized in good yields. Metal–B2 π-interactions in both the solid and solution state were confirmed by single-crystal X-ray analyses and their solution NMR and UV-vis absorption spectroscopy, respectively. The M(II) centers adopt a trigonal planar geometry and interact almost symmetrically with both boron atoms. The MB2 planes significantly twist out of the MX2 planes about the M-centroid(B–B) vector, with angles ranging from 47.0° to 85.5°, depending on the steric interactions between the diborene ligand and the MX2 fragment

Isolierung und Reaktivität eines s-Block-Metall-Antiaromaten

Das Konzept der Aromatizität und der Antiaromatizität ist seit langem bekannt, und zahlreiche Belege für dieses Phänomen wurden durch Moleküle, welche auf Elementen des p-, d- und f-Blocks des Periodensystems der Elemente (PSE) basieren, geliefert. Aufgrund der begrenzten Varianz des Oxidationszustandes von s-Block-Metallen konnten diese bisher nicht mit komplexen π-Bindungssystemen interagieren. Daher gibt es keine bzw. nur schlecht beschriebene Beispiele für antiaromatische Systeme mit s-Block-Metallen. Durch die Verwendung von spektroskopischen, strukturanalytischen und quantenchemischen Methoden konnte eine heterocyclische Verbindung hergestellt und charakterisiert werden, welche das Erdalkalimetall Beryllium enthält und signifikante Antiaromatizität aufweist. Weiterhin beschreiben wir die Reaktivität gegenüber Lewis-Basen und die chemische Reduktion dieser Verbindung

Strong Electron Donor Ligands and their Catalytic Applications

The coordination chemistry of several strong electron donor ligands, including anionic imidazol-4-ylidenes, cyclic bent allenes, carbodiphosphoranes, and carbodicarbenes were explored with transition metals including Au, Ag, Ru, Rh, Ir, and Fe. Chapter 2 explores the transition metal coordination chemistry of an anionic imidazol-4-ylidene. Ru complexes of this ligand were accessed by transmetalation of an anionic imidazol-4-ylidene Ag complex - the first instance of Ag mediated transmetalation of an anionic imidazolylidene. A coordinatively unsaturated Ru complex of this ligand was shown to decompose through a unique metal assisted proton transfer reaction. Rh complexes of this ligand have revealed its overall moderately strong donor ability. Chapter 3 details the synthesis of a family of Ru-hydrido species bearing strongly donating ‘cyclic bent allenes’ and reveals their very high activity in olefin hydrogenation catalysis. Chemoselective and diastereoselective hydrogenations, as well as hydrogenations of sterically hindered olefins are achieved at exceptionally low catalyst loadings. Chiral modifications of the cyclic bent allene ligands have been explored in Ir based systems. Chapter 4 explores the Fe chemistry of cyclic bent allenes and carbodiphosphoranes. These strong electron donors are shown to stabilize Fe in a rare highly unsaturated three-coordinate geometry in several instances. Chapter 5 details the synthesis of a new type of carbodicarbene, a ‘carbodicyclopropenylidene’, which is the first example of a carbodicarbene without heteroatomic stabilization. The main group and transition metal coordination chemistry of this ligand is investigated. The carbodicyclopropenylidene is shown also to be a strong electron donor.Ph.D.2017-11-30 00:00:0

Three-Coordinate, Cyclic Bent Allene Iron Complexes

Novel three-coordinate Fe complexes featuring 1,2-diphenyl-3,5-bis­(2,6-dimethylphenoxy)­pyrazolin-4-ylidine or “cyclic bent allene” (CBA) have been synthesized. Reaction with FeCl₂(PPh₃)₂ results in the loss of both phosphines to yield monomeric Fe­(CBA)­Cl₂. Treatment with 2 equiv of benzyl Grignard affords the three-coordinate alkylated product Fe­(CBA)­(Bn)₂. Exposure of the alkylated species to an atmosphere of CO results in reductive elimination of 1,3-diphenylpropanone and formation of trigonal-bipyramidal Fe­(CBA)­(CO)₄

A lean six sigma case study: an application of the "5s" techniques

This paper presents an application of the Lean Six Sigma DMAIC model. It is used to improve a plastic cup manufacturing process. The Improve Phase of the DMAIC model utilizes the amazingly simple, and yet effective, Japanese 5S techniques to achieve a dramatic improvement in the process