Synthesis, characterization, and crystal structure of aqua-bis-(4,4'-dimeth-oxy-2,2'-bi-pyridine)[μ-(2,3)-tartrato(4-)]dicopper(II) octa-hydrate.

Typical electroless copper baths (ECBs), which are used to chemically deposit copper on printed circuit boards, consist of an aqueous alkali hydroxide solution, a copper(II) salt, formaldehyde as reducing agent, an l-(+)-tartrate as complexing agent, and a 2,2'-bi-pyridine derivative as stabilizer. Actual speciation and reactivity are, however, largely unknown. Herein, we report on the synthesis and crystal structure of aqua-1κ-bis-(4,4'-dimeth-oxy-2,2'-bi-pyri-dine)-1κ ,;2κ ,-[μ-(2,3)-2,3-dioxidosuccinato-1κ , :2κ , ]dicopper(II) octa-hydrate, [Cu(CHNO)(CHO)(HO)]·8HO, from an ECB mock-up.

O-O Bond Formation and Liberation of Dioxygen Mediated by N -Coordinate Non-Heme Iron(IV) Complexes.

Formation of the O-O bond is considered the critical step in oxidative water cleavage to produce dioxygen. High-valent metal complexes with terminal oxo (oxido) ligands are commonly regarded as instrumental for oxygen evolution, but direct experimental evidence is lacking. Herein, we describe the formation of the O-O bond in solution, from non-heme, N -coordinate oxoiron(IV) species.

Genetic repertoires of anaerobic microbiomes driving generation of biogas.

Background: Biogas production is an attractive technology for a sustainable generation of renewable energy. Although the microbial community is fundamental for such production, the process control is still limited to technological and chemical parameters. Currently, most of the efforts on microbial management system (MiMaS) are focused on process-specific marker species and community dynamics, but a practical implementation is in its infancy.

Self-Assembly of Di(pyrazol-1-yl)pyridine-benzoic Acid on Underpotentially Deposited Ag from Solution.

Monolayers of 4-(2,6-di(1 H-pyrazol-1-yl)pyridine-4-yl)benzoic acid (DPP-BA) on Au substrates modified by an underpotential-deposited bilayer of Ag were studied by X-ray photoelectron spectroscopy (XPS), near edge X-ray absorption fine structure spectroscopy, and scanning tunneling microscopy. Highly crystalline layers are formed with molecules coordinatively bonding to the surface through the carboxylate moiety in a bidentate configuration. The molecules assemble to rows characterized by densely packed upright-orientated DPP units occupying an area of 41 Å.

Microbiome dynamics and adaptation of expression signatures during methane production failure and process recovery.

This study aimed to uncover microbial dynamics and transcriptional adaptations during mesophilic AD of maize silage and slurry. While one digester performed under optimal conditions, the investigations also evaluated the microbiome during a temperature drop mediated process failure accompanied by acidification and how it contributed to a process recovery. Composition and pathway activities were analyzed by whole genome shotgun (WGS) and metatranscriptome sequencing, respectively.

Oxygen Delivery as a Limiting Factor in Modelling Dicopper(II) Oxidase Reactivity.

Deprotonation of ligand-appended alkoxyl groups in mononuclear copper(II) complexes of N,O ligands L and L , gave dinuclear complexes sharing symmetrical Cu O cores. Molecular structures of these mono- and binuclear complexes have been characterized by XRD, and their electronic structures by UV/Vis, H NMR, EPR and DFT; moreover, catalytic performance as models of catechol oxidase was studied. The binuclear complexes with anti-ferromagnetically coupled copper(II) centers are moderately active in quinone formation from 3,5-di-tert-butyl-catechol under the established conditions of oxygen saturation, but are strongly activated when additional dioxygen is administered during catalytic turnover.

Controlled ligand distortion and its consequences for structure, symmetry, conformation and spin-state preferences of iron(II) complexes.

The ligand-field strength in metal complexes of polydentate ligands depends critically on how the ligand backbone places the donor atoms in three-dimensional space. Distortions from regular coordination geometries are often observed. In this work, we study the isolated effect of ligand-sphere distortion by means of two structurally related pentadentate ligands of identical donor set, in the solid state (X-ray diffraction, (57)Fe-Mössbauer spectroscopy), in solution (NMR spectroscopy, UV/Vis spectroscopy, conductometry), and with quantum-chemical methods.

Bulk spin-crossover in the complex [FeL(NCS)2] of a tris(pyridyl)ethane-derived N4-ligand--a temperature-dependent crystallographic study.

We have recently shown that the vacuum-deposited complex [Fe(II)L(NCS)2] (L: 1-{6-[1,1-di(pyridin-2-yl)ethyl]-pyridin-2-yl}-N,N-dimethylmethanamine) is capable of a thermally induced spin crossover (SCO) in direct contact with a graphite surface. The SCO significantly differs from the transition behaviour in the bulk phase (powder). In the present work, the assumption of virtually no intermolecular interaction in the powder is confirmed by comparison with the spin transition in acetone solution (T1/2 = 234[3] K, ΔT80 = 58[4] K), as monitored by temperature-dependent UV/Vis spectroscopy.

High intrinsic barriers against spin-state relaxation in iron(II)-complex solutions.

Slow relaxation: Exergonic high-spin→low-spin relaxation after photoexcitation has been found to be exceedingly slow in a class of iron(II) complexes with hexadentate imine ligands. The thermal activation barriers that arise between the quintet- and singlet-spin manifolds are the highest ever recorded for spin crossover of isolated molecules in free solution (see figure).

Spin Crossover in a Vacuum-Deposited Submonolayer of a Molecular Iron(II) Complex.

Spin-state switching of transition-metal complexes (spin crossover) is sensitive to a variety of tiny perturbations. It is often found to be suppressed for molecules directly adsorbed on solid surfaces. We present X-ray absorption spectroscopy measurements of a submonolayer of [Fe(II)(NCS)2L] (L: 1-{6-[1,1-di(pyridin-2-yl)ethyl]-pyridin-2-yl}-N,N-dimethylmethanamine) deposited on a highly oriented pyrolytic graphite substrate in ultrahigh vacuum.

Head-to-head comparison of left ventricular function assessment with 64-row computed tomography, biplane left cineventriculography, and both 2- and 3-dimensional transthoracic echocardiography: comparison with magnetic resonance imaging as the reference standard.

Objectives: This study was designed to compare the accuracy of 64-row contrast computed tomography (CT), invasive cineventriculography (CVG), 2-dimensional echocardiography (2D Echo), and 3-dimensional echocardiography (3D Echo) for left ventricular (LV) function assessment with magnetic resonance imaging (MRI).

Background: Cardiac function is an important determinant of therapy and is a major predictor for long-term survival in patients with coronary artery disease. A number of methods are available for assessment of function, but there are limited data on the comparison between these multiple methods in the same patients.

Tetrapodal amidoxime ligands I. Coordination isomerism due to self-complementary dimerization of a pyramidal cobalt(III) coordination module.

A bis-μ-amidoximato-bridged cobalt(III) dimer obtained with a new tetrapodal ligand possesses interesting structural parameters as a consequence of intramolecular hydrogen bonding intentionally built into the complex. Its synthesis and properties are described. The new ligand type combines attributes of two previously described ligand classes: It binds a metal ion in a tetrapodal pentadentate fashion and forms a pseudomacrocycle through hydrogen bonds, characteristic of chelating oxime ligands.

Tetrapodal pentadentate ligands: Single site reactivity and bond activation in iron(II) complexes.

Tetrapodal pentadentate ligands occupy five coordination positions in a coordination octahedron, thereby providing the metal ion with a square-pyramidal "coordination cap": In such complexes, all reactivity is focused on a single coordination site. The review highlights recent advances in the coordination chemistry of iron. With a variety of NN(4) ligands, the concept is being used to model non-heme active sites in biomolecules.

Early right ventricular systolic dysfunction in patients with systemic sclerosis without pulmonary hypertension: a Doppler Tissue and Speckle Tracking echocardiography study.

Background: Isovolumetric acceleration (IVA) is a novel tissue Doppler parameter for the assessment of systolic function. The aim of this study was to evaluate IVA as an early parameter for the detection of right ventricular (RV) systolic dysfunction in patients with systemic sclerosis (SSc) without pulmonary hypertension.

Methods: 22 patients and 22 gender- and age-matched healthy subjects underwent standard echocardiography with tissue Doppler imaging (TDI) and speckle tracking strain to assess RV function.

Is antiarrhythmia device implantation safe under dual antiplatelet therapy?

Background: Device implantations in patients on dual antiplatelet-therapy (DA-therapy) continue to rise. The aim of our study was to compile and analyze data on complications of antiarrhythmia device implantation under DA-therapy.

Methods: We prospectively collected data on all device implantations in our department from January 2008 until February 2009.

Implementation of seven echocardiographic parameters of myocardial asynchrony to improve the long-term response rate of cardiac resynchronization therapy (CRT).

Background: Cardiac resynchronization Therapy (CRT) is an effective therapy for chronic heart failure with beneficial hemodynamic effects leading to a reduction of morbidity and mortality. The responder rates, however, are low. There are various and contentious echocardiographic parameters of myocardial asynchrony.

Self-assembled monolayers of a bis(pyrazol-1-yl)pyridine-substituted thiol on Au(111).

Self-assembled monolayers (SAMs) of a bis(pyrazol-1-yl)pyridine-substituted thiol (bpp-SH) on Au (111)/mica were studied with scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), and near-edge X-ray absorption fine structure spectroscopy (NEXAFS). Using substrates precoated with perylene-3,4,9,10-tetracarboxylic acid dianhydride (PTCDA), preparation at elevated temperatures yields highly ordered layers whose structure is described by a rectangular (5 x radical3) unit cell containing one molecule. The bis(pyrazol-1-yl)pyridine (bpp) units exhibit pi-stacking along the 112 direction, and they are tilted significantly.

Head-to-tail interactions in tyrosine/benzophenone dyads in the ground and the excited state: NMR and laser flash photolysis studies.

The formation of head-to-tail contacts in de novo synthesized benzophenone/tyrosine dyads, bp logical sum Tyr, was probed in the ground and excited triplet state by NMR techniques and laser flash photolysis, respectively. The high affinity of triplet-excited ketones towards phenols was used to trace the geometric demands for high reactivity in the excited state. A retardation effect on the rates with increasing hydrogen-bond-acceptor ability of the solvent is correlated with ground-state masking of the phenol.

Circumferential 2D-strain imaging for the prediction of long term response to cardiac resynchronization therapy.

Background: Cardiac Resynchronization Therapy (CRT) leads to hemodynamic and clinical improvement in heart failure patients. The established methods to evaluate myocardial asynchrony analyze longitudinal and radial myocardial function. This study evaluates the new method of circumferential 2D-strain imaging in the prediction of the long-term response to CRT.

Gas-phase C-H and N-H bond activation by a high valent nitrido-iron dication and NH-transfer to activated olefins.

A tetrapodal pentadentate nitrogen ligand (2,6-bis(1,1-di(aminomethyl)ethyl)pyridine, 1) is used for the synthesis of the azido-iron(III) complex [(1)Fe(N3)]X2 where X is either Br or PF6. By means of electrospray ionization mass spectrometry, the dication [(1)Fe(N3)]2+ can be transferred into the gas phase as an intact entity. Upon collisional activation, [(1)Fe(N3)]2+ undergoes an expulsion of molecular nitrogen to afford the dicationic nitrido-iron species [(1)FeN]2+ as an intermediate, which upon further activation can intramolecularly activate C-H- and N-H bonds of the chelating ligand 1 or can transfer an NH unit in bimolecular reactions with activated olefins.

Interventricular septum hematoma during cineventriculography.

Background: Intraseptal hematoma and subsequent myocardial infarction due to accidental contrast agent deposition complicating diagnostic cineventriculography is a previously undescribed complication of angiography.

Case Presentation: A 61 year old man was admitted at intensive care unit because of unstable angina pectoris 1 hour after coronary angiography. Transthoracic contrast echocardiography showed a non-perfused area in the middle of interventricular septum with an increase of thickening up to 26 mm.

AMER1 regulates the distribution of the tumor suppressor APC between microtubules and the plasma membrane.

APC is a multifunctional tumor suppressor protein that negatively controls Wnt signaling, but also regulates cell adhesion and migration by interacting with the plasma membrane and the microtubule cytoskeleton. Although the molecular basis for the microtubule association of APC is well understood, molecular mechanisms that underlie its plasma membrane localization have remained elusive. We show here that APC is recruited to the plasma membrane by binding to APC membrane recruitment 1 (AMER1), a novel membrane-associated protein that interacts with the ARM repeat domain of APC.