层状配位聚合物犤Pb(NCS)2(bpea)n的合成,结构和非线性光学性质(bpea=1,2-双(4-吡啶基)乙烷)

室温下Pb(OAC)     

Electrospray Ionization Mass Spectrometry of Hexanitrohexaazaisowurtzitane (CL‐20)

Abstract

Hexanitrohexaazaisowurzitane (CL‐20) is a newly developed propellant and has been examined using negative ion electrospray mass spectrometry. The primary ions observed included adduct ions (M+Cl)^– and (M+ONO₂)^?.     

Do Secondary Electrostatic Interactions Influence Multiple Dihydrogen Bonds? AA−DD Array on an Amine-Borane Aza-Coronand: Theoretical Studies and Synthesis

Hydrogen bond plays a key role in a wide range of inorganic, organic, as well as biological systems. The understanding on how the chemical environment can affect this kind of interaction is crucial to predict its binding strength and consequently the robustness and the dynamic properties of many supramolecular systems. In this paper a new donor-acceptor complex was synthesized and characterized by SCXRD, showing for the first time in an organic system an AA−DD pattern of a particular hydrogen interaction, called dihydrogen bond. Over 250 functionals were computationally evaluated to select the best method to reproduce the binding interaction geometry of this new pattern. Moreover, a new vector force model was used to split the contribution of primary and secondary electrostatic interactions (SEIs), in order to evaluate how the latter one can modify the binding strength of this unusual hydrogen-hydrogen interaction.     

One-step Synthesis of PCL-Urethane Networks using a Crosslinking/de-crosslinking Agent

Thermally reversible cross-linked polycaprolactone-urethane (PCL-U) was prepared in one-step procedure. The PCL-U networks were synthesized from a di-isocyanate (4,4′-methylene bis(cyclohexylisocyanate) (HMDI) and hydroxyl bearing macromers and monomers: hydroxy-terminated PCL, glycerol and a di-alcohol Diels-Alder (DA) adduct. This adduct was used to introduce both diene and dienophile functions in the structure and also to protect the maleimide functions from polymerization. The thermoresponsive behavior of the material was characterized by commonly used methods such as solubility tests at different temperatures and differential scanning calorimetry analyses to highlight rDA reactions and also by rheological analysis. The effects of the cooling rate, the molar mass of polycaprolactone as well as the molar ratio [di-Isocyanate]/[PCL-diol] on the cross-linking/de-cross-linking temperatures were also analyzed. The reversible networks obtained have a self-healing behavior.     

Carbene adduct of cyclopalladated ferrocenylimine‐assisted synthesis of aminopyridine derivatives by the amination of chloropyridines with primary and secondary amines

An efficient, simple way to synthesize aminopyridine derivatives is presented, based on Buchwald–Hartwig aminations. Using 1 mol% N‐heterocyclic carbene adduct of cyclopalladated ferrocenylimine in the presence of 1.5 equiv. ^tBuOK as base in dioxane at 110°C offered moderate to excellent yields in the reaction of chloropyridines with primary and secondary amines, including sterically hindered amines and alkyl amines.     

A novel MgI2 mediated unusual dimerization-spirocyclopropanation of bromo isomerised Morita-Baylis-Hillman adduct of isatin: a facile synthesis of 3-spirocyclopropane-2-oxindole derivatives

A novel magnesium iodide mediated unusual dimerization-spirocyclopropanation of bromo isomerised Morita-Baylis-Hillman adducts of isatin afforded highly functionalized 3-spirocyclopropane-2-oxindole derivatives as regioisomers in good combined yield. It has been observed that the regioselectivity is dependent on the nature of electron withdrawing group at the activated position. A plausible mechanism involving organomagnesium reagent has been proposed.     

SOME INVESTIGATIONS ON POLY(SULPHUR OXIDE) AND ITS REACTION WITH SILICON TETRACHLORIDE

Abstract

Poly(sulphur oxide) has been prepared by the low temperature thermal decomposition of the lower oxides of sulphur. This yellow, elastic solid resists water hydrolysis. It is unstable at room temperature when stored under vacuum and decomposes slowly to a powdery yellow white cyclic(sulphur oxide) and sulphur dioxide. In the presence of silicon tetrachloride, the thermal decomposition gives rise to an adduct of the lower oxide of sulphur along with the poly(sulphur oxide). The adduct hydrolyses to silica, hydrogen chloride, hydrogen sulphide and hydrogen sulphite. Based on the analysis of the hydrolysed products and the IR data, the adduct is assigned a formula of SiCl₄·2(SO), in which the silicon is hexacoordinated.     

Synthesis and characterization of 3-picoline adducts of bis(O,O′-ditolyl/dibenzyl/diphenyl dithiophosphato)cobalt(II) complexes: crystal structure of 3-picoline adducts Co{S2P(OC6H4Me-p)2}2(NC5H4Me-3)2

Bis(O,O′-ditolyl/dibenzyl/diphenyl dithiophosphato)cobalt(II) (1–5) with 3-picoline, Co{S₂P(OR)₂}₂(NC₅H₄Me-3)₂ (R?=?o-, m-, p-C₆H₄Me, CH₂Ph, Ph) have been synthesized by in situ reaction of 3-picoline and CoCl₂·6H₂O in aqueous medium followed by the addition of aqueous solution of NH₄S₂P(OR)₂. The single crystal structure of Co{S₂P(OC₆H₄Me-p)₂}₂(NC₅H₄Me-3)₂ shows that geometry around cobalt(II) is distorted octahedral with two 3-picoline molecules in trans positions. These Co(II) dithiophosphate complexes (1–5) have been characterized by elemental analyses, spectroscopic techniques (UV-Vis, IR), and magnetic moment measurements.     

Lewis Acid Base Reactions between Boron Trifluoride and Complex Oxoanions as a Versatile Access to Fluorooxoanions: Synthesis of Sodium (Trifluoroborato)sulfate

Na₂SO₄BF₃, synthesized in a closed vessel from BF₃ and Na₂SO₄ at 603 K, crystallizes in the triclinic space group P$\bar{1}$ (a = 6.6033(2), b = 6.6328(2), c = 6.6349 (1) Å, α = 84.542(2), β = 84.458(1) and γ = 65.762(1)°). The novel fluorooxo anion [SO₄BF₃]^2– displays a structure similar to the disulfate anion S₂O₇^2–. Heating the title compound in the absence of BF₃ in the gas phase leads to decomposition even at 553 K, which is below the temperature of synthesis under BF₃ pressure.     

Identification of modification sites on human serum albumin and human hemoglobin adducts with houttuynin using liquid chromatography coupled with mass spectrometry

Houttuynin, a β‐keto aldehyde compound, is the major active ingredient in herba houttuyniae injection. The injection was once used as an anti‐inflammatory drug associated with occasional serious hypersensitivity reactions in the clinic, which were proposed to be related to the formation of protein adducts. N^α‐Boc‐lysine, FEEM and IVTNTT were used as model amino acids or peptides containing one nucleophilic residue to investigate adduct types by liquid chromatography coupled with ion trap mass spectrometry (LC/MSⁿ) and high‐resolution quadrupole time‐of‐flight mass spectrometry (Q‐TOF MS). These adducts were respectively characterized as Schiff bases formed by 1:1 reaction of houttuynin with lysine or N‐terminal residue and pyridinium adducts by 2:1 reaction. LC/MSⁿ analysis of trypsin digests of HSA/Hb incubations with houttuynin revealed that houttuynin‐modified HSA adducts were formed mainly at N‐terminal amino acid and lysine residues, specifically at Lys‐212, Lys‐414 and Lys‐525 for Schiff base adducts, and at Lys‐414 and Lys‐432 for pyridinium adducts, and houttuynin adducted more readily with N‐terminal valine of the α‐ and β‐chains in Hb and lysine amine (Lys‐62) of the β‐chain for Schiff base adducts. The results showed the direct modification of houttuynin to HSA/Hb in vitro, which was speculated to be responsible for the adverse reactions induced by houttuyniae injection. Copyright © 2012 John Wiley & Sons, Ltd.