Contributors:Matthias Mastalir, Mathias Glatz, Berthold Stöger, Matthias Weil, Ernst Pittenauer, Günter Allmaier, Karl Kirchner
The synthesis of a series of vanadium, chromium, and manganese PNP complexes of the types [M(PNP)Cl3] (M=V, Cr) and [M(PNP)Cl2] (M=Cr, Mn) is reported. Vanadium and manganese PNP pincer complexes are described for the first time. All complexes are characterized by their magnetic moments, elemental analysis, and ESI MS. In addition, some compounds are characterized by X-ray crystallography. In a preliminary study, these complexes catalyze the oxidative homo-coupling of aryl Grignard reagents in the presence of MeI as oxidizing agents to give symmetrical biaryls, but are inactive in Kumada cross-coupling reactions. The reactivity of V(III), Cr(III), Cr(II) and Mn(II) is compared with related Fe(II) and Co(II) complexes of the types [Fe(PNP-iPr)Cl2], and [Co(PNP-iPr)Cl2]. In all cases, good to excellent isolated yields are obtained. However, since the respective metal chlorides in the absence of PNP ligands exhibited comparable reactivities, the new PNP complexes offer no real advantage for this type of coupling reactions.
The reconfigurable cube mechanism (RCM) is a puzzle linkage made by eight connected sub-cubes. It is equivalent to a single-loop 8R spatial linkage with eight different topological configurations and changeable mobility. Unlike other common reconfigurable mechanisms, the topological configuration of the RCM is featured not only by its “relative joint orientations” but also the “relative joint distances.” These two topological properties, namely “orientation isomorphism” and “distance isomorphism” in this study, completely define the configuration isomorphism of the RCM. We will present a unified screw-based approach for the mobility analysis and the configuration isomorphism identification of the RCM. Two illustrative examples are provided for demonstrating the isomorphism identification of this special mechanism. The first example will show that two topologically identical RCMs may be seemingly significantly different in their appearance. Oppositely, the second example will demonstrate that two plausibly identical RCMs may have identical relative joint orientations but their relative joint distances are completely distinct.
A terpyridyl-imidazole based heteroditopic Ru(II) complex of composition [(phen)2Ru(tpy-Hbzim-dipy)](ClO4)2] (1), where tpy-Hbzim-dipy=4′-[4-(4,5-Di-pyridin-2-yl-1H-imidazol-2-yl)-phenyl]-[2,2′;6′,2″] terpyridine and phen=1,10-phenanthroline is designed and structurally characterized in this work for the construction of multifunctional Boolean and Fuzzy logic devices. The designed complex acts as a red-color emitter and has a free terpyridine moiety which can be coordinated to a cationic guest and an imidazole motif capable of interacting with selective anionic guests through hydrogen bonding. Consequently, modulation of physicochemical properties of the complex by the anionic and cationic guests was examined through different optical channels. The metalloreceptor acts as a chromogenic sensor for F−, AcO−, CN−, and H2PO4− among the anions, while for Fe2+ among bivalent 3d cations in acetonitrile. Based on various output signals with a particular set of anionic and cationic inputs, the complex mimics the functions of four-inputs NOR logic gate and complicated function of memory device. More importantly, we also report the implementation of Fuzzy logic approach to develop an infinite-valued logic system based on either the absorbance or luminescence dependence of the complex upon concentration of different ionic inputs. In conjunction with the experimental investigation, density functional theory (DFT) and time-dependent density functional theory (TD-DFT) studies were also carried out to investigate the structural and electronic properties of the receptor.
Cenozoic conglomerates are exposed discontinuously along the length of the Yarlung Tsangpo suture zone on the southern margin of the Gangdese arc. These conglomerates (the “Gangdese Conglomerates” herein) record a crucial stage in the uplift and erosion histories of the southern Tibet after the initial India–Asia collision. In the Mt. Kailas area, the Gangdese Conglomerates strata consist of multiple sedimentary cycles and each cycle is a fining-upward sequence that was deposited by alluvial fan, braided-river and delta systems. Whereas in the Xigaze area, the Gangdese Conglomerates strata comprise a coarsening-upward sequence that was deposited by delta, braided-river and alluvial fan systems. Based on the detrital and igneous zircon U–Pb ages, the depositional ages of the Gangdese Conglomerates are late Oligocene to early Pliocene (ca. 26–5Ma) in the Mt. Kailas area, late Oligocene to middle Miocene (ca. 26–15Ma) in the Xigaze area, and late Oligocene to early Miocene (ca. 26–19Ma) in the Zedong area. Paleocurrent measurements and provenance data (i.e., conglomerate clast composition, sandstone petrology and detrital zircon age) indicate that the initial detritus of the Gangdese Conglomerates were entirely derived from the north (mainly from the Gangdese arc). Sediment resulting from denudation to the south (the Xigaze forearc basin, the Yarlung Tsangpo suture zone and the northern margin of the Indian plate) first appeared by the early Miocene (ca. 19Ma) and subsequently increased in abundance gradually. Our new results, together with previous data from the Xigaze area, reveal 3 major stages in the evolution of the Yarlung Tsangpo River system: (1) the southward-flowing stage (ca. 26–19Ma) featured southward-draining transverse rivers that transported materials from the Gangdese arc southward. Southward paleocurrents in the Gangdese Conglomerates indicate a northern source. (2) The westward-flowing stage (ca. 19–15Ma) developed due to the uplift of the suture zone and Tethys Himalaya to the south. Northward-draining rivers began to develop, and lakes resembling a string of beads formed and finally connected together, initiating the westward-flowing paleo-Yarlung Tsangpo River. Westward paleoflows were recorded in the Gangdese Conglomerates. (3) The eastward-flowing stage (ca. 15Ma–present) resulted from differential uplift and denudation of the southern Tibet, which reversed the direction of the young Yarlung Tsangpo River by ca. 15Ma. The deposition of the Gangdese Conglomerates was controlled by eastward paleoflows. At this point, the modern eastward-flowing Yarlung Tsangpo River system was established.
This paper describes program betaFIT, which performs least-squares fits of sets of one-dimensional (or radial) potential function values to four different types of sophisticated analytic potential energy functional forms. These families of potential energy functions are: the Expanded Morse Oscillator (EMO) potential [J Mol Spectrosc 1999;194:197], the Morse/Long-Range (MLR) potential [Mol Phys 2007;105:663], the Double Exponential/Long-Range (DELR) potential [J Chem Phys 2003;119:7398], and the “Generalized Potential Energy Function (GPEF)” form introduced by Šurkus et al. [Chem Phys Lett 1984;105:291], which includes a wide variety of polynomial potentials, such as the Dunham [Phys Rev 1932;41:713], Simons–Parr–Finlan [J Chem Phys 1973;59:3229], and Ogilvie–Tipping [Proc R Soc A 1991;378:287] polynomials, as special cases. This code will be useful for providing the realistic sets of potential function shape parameters that are required to initiate direct fits of selected analytic potential functions to experimental data, and for providing better analytical representations of sets of ab initio results.
This paper describes computer program RKR1, which implements the first-order semiclassical Rydberg–Klein–Rees procedure for determining the potential energy function for a diatomic molecule from a knowledge of the dependence of the molecular vibrational energies Gv and inertial rotation constants Bv on the vibrational quantum number v. RKR1 allows the vibrational energies and rotational constants to be defined in terms of: (i) conventional Dunham polynomial expansions, (ii) near-dissociation expansions (NDE׳s), or (iii) the mixed Dunham/NDE “MXR” functions introduced by Tellinghuisen [J Chem Phys 2003; 118: 3532]. Internal convergence tests ascertain and report on the precision of the resulting turning points. For cases in which only vibrational data are available, RKR1 also allows an overall potential to be constructed by combining directly-calculated well widths with inner turning points generated from a Morse function. It can also automatically smooth over irregular or unphysical behavior of the steep inner wall of the potential.
Contributors:Sjors Verlaan, Terry J. Aspray, Juergen M. Bauer, Tommy Cederholm, Jaimie Hemsworth, Tom R. Hill, Jamie S. McPhee, Mathew Piasecki, Chris Seal, Cornel C. Sieber, Sovianne ter Borg, Sander L. Wijers, Kirsten Brandt
Sarcopenia, the age-related decrease in muscle mass, strength, and function, is a main cause of reduced mobility, increased falls, fractures and nursing home admissions. Cross-sectional and prospective studies indicate that sarcopenia may be influenced in part by reversible factors like nutritional intake. The aim of this study was to compare functional and nutritional status, body composition, and quality of life of older adults between age and sex-matched older adults with and without sarcopenia.
Ruthenium(II) complexes (1–6) supported by a series of 2-oxo-1,2-dihydroquinoline-3-carbaldehyde substituted thiosemicarbazone ligands [2-oxo-1,2-dihydroquinoline-3-carbaldehyde thiosemicarbazone (L1), 2-oxo-1,2-dihydroquinoline-3-carbaldehyde N-methyl thiosemicarbazone (L2), 2-oxo-1,2-dihydroquinoline-3-carbaldehyde N-phenylthiosemicarbazone (L3)] have been synthesized and structurally characterized by analytical, spectroscopic methods and X-ray crystallographic technique. The studies revealed that the ligands act as mononegative tridentate in ruthenium(II) complexes and a distorted octahedral geometry has been proposed for the complexes. In addition, the complexes have been found to catalyze the amidation of alcohols with amines in the presence of KtBuO–toluene system. The catalyst 3 displayed higher activity in substrates, including phenyl-, pyridine-, furan-, and thiophene-substituted alcohols with primary and secondary amines. The protocol is highly attractive because of easily available starting materials, high atom efficiency and environmental friendliness.
The rational design and construction of a novel trinuclear macrocycle based on half-sandwich ruthenium was herein elaborated in detail, and consequently, fully characterized by 1D NMR, IR, EA and single crystal X-ray analysis, revealing its specific molecular structure which was a classic three-member ruthenium ring bridged by an organic linker [(E)-2-(2-(pyridin-4-yl)vinyl)quinolin-8-ol (HL)]. To further examine its photo and electronic properties, the mothed of UV–Vis and CV was carried out at ambient temperature, revealing it has a good application for catalyzing water oxidation under alkaline conditions.
Contributors:Sandra Posch, Camilo Aponte-Santamaría, Richard Schwarzl, Andreas Karner, Matthias Radtke, Frauke Gräter, Tobias Obser, Gesa König, Maria A. Brehm, Hermann J. Gruber, Roland R. Netz, Carsten Baldauf, Reinhard Schneppenheim, Robert Tampé, Peter Hinterdorfer
The von Willebrand factor (VWF) is a glycoprotein in the blood that plays a central role in hemostasis. Among other functions, VWF is responsible for platelet adhesion at sites of injury via its A1 domain. Its adjacent VWF domain A2 exposes a cleavage site under shear to degrade long VWF fibers in order to prevent thrombosis. Recently, it has been shown that VWF A1/A2 interactions inhibit the binding of platelets to VWF domain A1 in a force-dependent manner prior to A2 cleavage. However, whether and how this interaction also takes place in longer VWF fragments as well as the strength of this interaction in the light of typical elongation forces imposed by the shear flow of blood remained elusive. Here, we addressed these questions by using single molecule force spectroscopy (SMFS), Brownian dynamics (BD), and molecular dynamics (MD) simulations. Our SMFS measurements demonstrate that the A2 domain has the ability to bind not only to single A1 domains but also to VWF A1A2 fragments. SMFS experiments of a mutant [A2] domain, containing a disulfide bond which stabilizes the domain against unfolding, enhanced A1 binding. This observation suggests that the mutant adopts a more stable conformation for binding to A1. We found intermolecular A1/A2 interactions to be preferred over intramolecular A1/A2 interactions. Our data are also consistent with the existence of two cooperatively acting binding sites for A2 in the A1 domain. Our SMFS measurements revealed a slip-bond behavior for the A1/A2 interaction and their lifetimes were estimated for forces acting on VWF multimers at physiological shear rates using BD simulations. Complementary fitting of AFM rupture forces in the MD simulation range adequately reproduced the force response of the A1/A2 complex spanning a wide range of loading rates. In conclusion, we here characterized the auto-inhibitory mechanism of the intramolecular A1/A2 bond as a shear dependent safeguard of VWF, which prevents the interaction of VWF with platelets.