Simultaneous targeted immobilization of anti-human IgG-coated nanotubes and anti-mouse IgG-coated nanotubes on the complementary antigen-patterned surfaces via biological molecular recognition

Introduction of self-assembly in nanometer-sized building blocks is expected to accomplish bottom-up fabrications in a more reproducible, efficient, and economic manner; however, it is necessary to selectively place multiple types of nano-building blocks (e.g., metal nanotubes and semiconductor nanotubes) at specific locations on surfaces with high precision and reproducibility for more complex nanometer-scale device assemblies. Biological molecular recognition such as antibody-antigen bindings may be suitable to use in the building-block assembly since nature always assembles materials with complex functions and structures at room temperature reproducibly. Our approach is to immobilize antibody-coated nanotubes at specific complementary binding positions patterned on surfaces. To demonstrate this hypothesis, two types of nanotubes coated with different antibodies were anchored selectively onto their complementary antigen areas, patterned by tips of atomic force microscope (AFM). Because those nanotubes can be coated by various metals and semiconductors with controlled morphologies, this outcome opens the possibility to accomplish the proposed unconventional device fabrication methodology that antibody nanotubes coated with different types of metals/semiconductors can be self-assembled on antigen-patterned surfaces via biological molecular recognition.     

Mixed ligand palladium(II) complexes of oxalate and malonate with vitamin-B6 molecules: synthesis,crystal structure and kinetics

The synthesis of six mononuclear palladium complexes of general formula [Pd(ox)/(mal)L₂] and [Pd(ox)/(mal)L] (ox = oxalate, mal = malonate, both L and L are vitamin-B₆ molecules (I), L = pyridoxine, pyridoxal and L = pyridoxamine) has been achieved. The structures of these compounds were established by elemental analysis, i.r. and ¹³C-n.m.r. [Pd(oxalate)(pyridoxine)₂] was analyzed by single crystal X-ray diffraction. It exhibits square planar coordination with bond lengths 2.015 (2) Å for Pd—N and 2.010 (2) Å for Pd—O. The interaction of [Pd(ox)₂]^2– and [Pd(mal)₂]^2– with L has been followed kinetically in order to look into the nature of products and the mechanism of formation under the conditions [Pd^II-chelate] [L] and [L].     

Thermoanalytical study of the solid state reaction between hydrated ZnO and Fe2O3

The hydrated oxides which are formed by the addition of ammonium bi-carbonate to a solution of Zn(NO₃)₂ and Fe(NO₃)₃, and drying the precipitates at 110° are zinc hydroxy carbonate(I) and iron(III) oxide gel(II), respectively. A new, derived derivative thermogravimetric curve along with conventional DTA and DTG methods have been used to study the reaction between (I) and (II) in two components system.A mixture of (I) and (II) subjected to grinding yields about 16% zinc ferrite precursor. In a sample prepared by coprecipitation from the mixed nitrate solution and drying at 110°, nearly 70% precursor is formed. The formation of zinc ferrite spinel reported to take place at low temperature in such cases appears to be related with the formation of the precursor, and reactivity and phase transformation temperature in Fe₂O₃.

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Zusammenfassung Die durch Zugabe von Ammoniumbicarbonat zu einer Lösung von Zn(NO₃)₂ und Fe(NO₃)₃ und Trocknung des Niederschlags bei 110° gebildeten hydratisierten Oxide sind Zinkhydroxycarbonat (I) bzw. Eisen(III)oxidgel (II). Eine neue derivierte derivative thermogravimetrische Kurve wurde gemeinsam mit den konventionellen DTA und DTG Methoden zum Studium der Reaktion zwischen (I) und (II) in Zweikomponentensystemen eingesetzt.Das Gemisch von (I) und (II) ergibt beim Mahlen etwa 16% Zinkferrit »Prekursor«. In einer durch Mitfällung der gemischten Nitrate und Trocknung bei 110° erhaltenen Probe wurde fast 70 % »Prekursor« gebildet. Die Bildung von Zinkferritspinell, über dessen Entstehung in solchen Fällen bei niedrigen Temperaturen berichtet wird, scheint mit der Bildung des »Prekursors« verbunden zu sein, sowie mit der Reaktivität und der Phasenübergangstemperatur in Fe₂O₃.

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Résumé Les oxydes hydratés formés lors de l'addition du bicarbonate d'ammonium à une solution de Zn(NO₃)₂ et de Fe(NO₃)₂ suivie du séchage du précipité à 110°, sont l'hydroxy-carbonate de zinc(I) et le gel de l'oxyde de fer(III) (II). On a utilisé une nouvelle technique de thermogravimétrie en dérivation, ainsi que les méthodes d'ATD et TGD conventionnelles, pour étudier la réaction entre (I) et (II) dans le système à deux composants.Un mélange de (I) et de (II), soumis au broyage, donne environ 16 p.c. de ferrite de zinc «précurseur», tandis qu'un échantillon préparé par coprécipitation à partir de la solution des nitrates mixtes et séchage à 110°, en donne environ 70 p.c.La formation du spinelle de ferrite de zinc décrite comme ayant lieu, dans des cas similaires, à des températures faibles, paraît être en rapport avec la formation du «précurseur» ainsi qu'avec la réactivité et la température de la transformation de phase de Fe₂O₃.

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Zn(NO₃)₂ Fe(NO₃)₃, , 110°, , , (I) (II). , , I II . I II, , 16% , . , 110°, 70% , . « » , Fe₂O₃.

     

Observation of a possible pure electric quadrupole transition in solid Cs2NaSmCl6

A no-phonon transition has been observed in Cs₂NaSmCl₆ at 6355 cm^?1. This transition is assigned, in octahedral symmetry, as E″_u(⁶H_{$\text{5}\text{2}$}) → E'_u(⁶F_{$\text{1}\text{2}$}) and is proposed to be of pure electric quadrupole origin. A comparison between the experimental and calculated intensity and the orientation-dependent intensity of an associated vibronic transition lend support to this assignment.     

Binding of amino acids into a novel multiresponsive ferrocene receptor having an ene backbone

[reaction: see text] Receptor 1 featuring two open arms, multipoint binding sites, and unsaturated linkers on a ferrocene platform shows strong 1:1 binding to unprotected alpha-amino acids (UV-vis, fluorescence, CV, ITC, NMR, and ESI-MS). NMR and ESI-MS studies suggest an encapsulative binding mode involving the alpha,beta-unsaturated carbonyl residue (site for -NH3+, interaction A) and the terminal -OH groups (site for -COO-, interaction B).     

Room temperature phosphorescence from organic luminogens in“non-crystalline” state

ABSTRACT

The field of room temperature phosphorescence (RTP) from purely organic materials has made rapid strides in recent years primarily due to its tremendous promise in the areas of photovoltaics, photocatalysis, bioimaging, sensing, etc. Although, the RTP properties, at one time, were considered to be exclusive features of organometallic and inorganic phosphors, a great progress in the molecular design coupled with a much better understanding of the triplet state stabilisation has led to the creation of a plethora of organic RTP materials in the current decade. In this focussed review, a special category of organic luminogens which, rather remarkably, exhibit efficient RTP emission in amorphous or fluidic state is discussed. A few selected examples of such ‘non-crystalline’ organic RTP luminogens are highlighted with an emphasis on the basic design principles and the strategies to increment the phosphorescence efficiency.     

Calculation of the A term of magnetic circular dichroism based on time dependent-density functional theory I. Formulation and implementation

A procedure for calculating the A term and the A/D ratio of magnetic circular dichroism (MCD) within time-dependent density functional theory (TD-DFT) is described. Utilizing an implementation of the MCD theory within the Amsterdam Density Functional program, the A term contributions to the MCD spectra of MnO(4) (-), CrO(4) (2-), VO(4) (3-), MoO(4) (2-), VO(4) (3-), MoS(4) (2-), Se(4) (2+), Te(4) (2+), Fe(CN)(6) (4-), Ni(CN)(4) (2-), trichlorobenzene, hexachlorobenzene, tribromobenzene, and hexabromobenzene are calculated. For the most part, agreement between theory and experiment for A/D ratios and the relative magnitude of A terms is found to be good, leading to simulated spectra that are similar in appearance to those derived from measurements. The A terms are found to be too small whenever comparison with experiment was possible, probably due to the neglect of environment effects on the incident radiation and the relative low accuracy of dipole strengths calculated within TD-DFT.     

Synthetic Applications of the Baylis–Hillman Reaction: Simple and Convenient Synthesis of Five Important Insect Pheromones

A simple and convenient synthesis of five important insect pheromones by means of Baylis–Hillman adducts is described, i.e., of (2E,4S)‐2,4‐dimethylhex‐2‐enoic acid ( 1 ), a mandibular‐gland secretion of the male carpenter ant in the genus Camponotus, of (+)‐(S)‐manicone ( 2 ) and (+)‐(S)‐normanicone ( 3 ), two mandibular‐gland constituents of Manica ants, and of (+)‐dominicalure‐I ( 6 ) and (+)‐dominicalure‐II ( 7 ), two aggregation pheromones of the lesser grain borer Rhyzopertha dominica (F). For the first time, the potential of the Baylis–Hillman chemistry for the stereoselective synthesis of trisubstituted olefins was successfully applied to the synthesis of these pheromone compounds.     

Spectroscopic evidence for the formation of a four-coordinate Co2+ cobalamin species upon binding to the human ATP:cobalamin adenosyltransferase

The human adenosyltransferase hATR converts exogenous cobalamin into coenzyme B12 by transferring the adenosyl group from cosubstrate ATP to a transiently formed Co1+cobalamin (Co1+Cbl) species. A particularly puzzling aspect of hATR function is that the midpoint potential for Co2+Cbl --> Co1+Cbl reduction is below that of readily available biological reductants. Our magnetic circular dichroism and electron paramagnetic resonance spectroscopic studies reported here reveal that, in the absence of ATP, the interaction between Co2+Cbl and hATR promotes partial conversion of the cofactor to its "base-off" form in which a water molecule occupies the lower axial position. This interaction becomes much stronger in the presence of ATP, leading to the formation of an unprecedented Co2+Cbl species with spectroscopic signatures consistent with an essentially four-coordinate, square-planar Co2+ center. This unusual Co2+Cbl coordination is expected to raise the Co2+/1+ reduction potential well into the physiological range.