Über Münzmetall‐Quecksilber‐Chalkogenidhalogenide. IV1) Hydrothermalsynthese und Kristallstruktur von CuHgSI und CuHg2S2I

On Coinage Metal Mercury Chalcogenide Halides. IV Hydrothermal Synthesis and Crystal Structure of CuHgSI and CuHg₂S₂I The hydrothermal reaction of CuI with α‐HgS in diluted aqueous HI‐solution as solvent at 180 °C yields dark red crystals of CuHgSI. The compound crystallizes orthorhombic in the space group Pna2₁ with a = 718.3(1) pm, b = 834.3(2) pm and c = 698.9(1) pm and Z = 4. CuHg₂S₂I was obtained by the hydrothermal reaction of CuI with α‐HgS in diluted HI‐solution at 300 °C as black crystals. The compound crystallizes orthorhombic in the space group Cmc2₁ with a = 1261.8(3) pm, b = 722.4(1) pm and c = 693.7(1) pm and Z = 4. Both crystal structures could be explained as distorted version of the Wurtzite structure type in which two different types of anion‐lattices are built up.     

The Counterion Effect on the Assembly of Coordination Networks of Cationic (η3‐Allyl)palladium Complexes Containing 3,5‐Dimethyl‐4‐nitro‐1H‐pyrazole

Two new (η³‐allyl)palladium complexes containing the ligand 3,5‐dimethyl‐4‐nitro‐1H‐pyrazole (Hdmnpz) were synthesized and characterized as [Pd(η³‐C₃H₅)(Hdmnpz)₂]BF₄ ( 1 ) and [Pd(η³‐C₃H₅)(Hdmnpz)₂]NO₃ ( 2 ). The structures of these compounds were determined by single‐crystal X‐ray diffraction to evaluate the intermolecular assembly. Each complex exhibits similar coordination behavior consistent with cationic entities comprised of two pyrazole ligands coordinated with the [Pd(η³‐C₃H₅)]⁺ fragment in an almost square‐planar coordination geometry. In 1 , the cationic entities are propagated through strong intermolecular H‐bonds formed between the pyrazole NH groups and BF ions in one‐dimensional polymer chains along the a axis. These chains are extended into two‐dimensional sheet networks via bifurcated H‐bonds. New intermolecular interactions established between NO₂ and Me substituents at the pyrazole ligand of neighboring sheets give rise to a three‐dimensional network. By contrast, compound 2 presents molecular cyclic dimers formed through N? H???O H‐bonds between two NO counterions and the pyrazole NH groups of two cationic entities. The dimers are also connected to each other through C? H???O H‐bonds between the remaining O‐atom of each NO ion and the allyl CH₂ H‐atom. Those interactions expand in a layer which lies parallel to the face (101).     

Studies on Hydroiodination and Deconjugation of 5—Aryloxy—（thiophenyl）—3—pentyn—2—one

One-pot hydroiodination and deconjugation of 5-aryloxy(or thiophenyl)-3-pentyn-2-one with a reagent system of sodium iodide/trimethylsilyl chloride/water in acetonitrile at 25℃ have been described.The plasuible mechanism was discussed.The reaction provided a simple and useful method for the preparation of (Z)-β-substituted β，γ-enones and (Z)-β-substituted α，β-unsaturated ketones.     

A concept for bifocal contact‐ or intraocular lenses: liquid single crystal hydrogels (“LSCH”)

The synthesis of liquid single crystal hydrogels (“LSCH”) in suitable molds offers an innovative concept to realize bifocal contact‐ or intraocular‐lenses. LSCH combine the properties required for applications as bifocal ophthalmic lenses: the soft and water‐containing hydrogel enables oxygen permeation and exhibits high birefringence due to the liquid crystalline phase structure built up by rigid rod‐like amphiphiles. Via a photo‐initiated crosslinking reaction of aqueous solutions of monomeric lyotropic liquid crystalline amphiphiles in the macroscopically ordered liquid crystalline state, we obtain optically uniaxially ordered and transparent LSCH. The orientation process and the phase structure of the anisotropic hydrogel is analyzed by deuterium NMR‐spectroscopy. Copyright © 2002 John Wiley & Sons, Ltd.     

Syntheses and characterizations of poly[2‐(dimethylamino)ethyl methacrylate]–poly(propylene oxide)–poly[2‐(dimethylamino)ethyl methacrylate] ABA triblock copolymers

A novel, near‐monodisperse, well‐defined ABA triblock copolymer, poly[2‐(dimethylamino)ethyl methacrylate]‐b‐poly(propylene oxide)‐b‐poly[2‐(dimethylamino)ethyl methacrylate], was synthesized via oxyanion‐initiated polymerization. The initiator was a telechelic‐type potassium alcoholate prepared from poly(propylene glycol) and KH in dry tetrahydrofuran. The copolymers produced were characterized by Fourier transform infrared, ¹H NMR, and gel permeation chromatography (GPC). GPC and ¹H NMR analyses showed that the products obtained were the desired copolymers, with narrow molecular weight distributions (ca. 1.09–1.11) very close to that of the original poly(propylene glycol). ¹H NMR, surface tension measurements, and dynamic light scattering all indicated that the triblock copolymer led to interesting aqueous solution behaviors, including temperature‐induced micellization and very high surface activity. © 2002 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 624–631, 2002; DOI 10.1002/pola.10144     

Tirucallane Triterpenoid Saponins from Munronia delavayi Franch

Four new tirucallane triterpenoid saponins, named munronosides I–IV ( 2 – 5 ), along with three known triterpenoids, sapelin B ( 1 ), melianodiol, and (3β)‐22,23‐epoxytirucall‐7‐ene‐3,24,25‐triol, were isolated from the EtOH extract of the whole plants of Munronia delavayi Franch by chromatographic methods. On the basis of spectroscopic evidences, the structures of 2 – 5 were elucidated as (20S,23R,24S)‐21,25‐epoxy‐29‐{{O‐β‐d‐ glucopyranosyl‐(1→3)‐O‐[α‐l‐ rhamnopyranosyl‐(1→6)]‐β‐d‐ glucopyranosyl}oxy}‐23,24‐dihydroxytirucall‐7‐ene‐3,21‐dione ( 2 ), (3β,20S,23R,24S)‐21,25‐epoxy‐29‐{{O‐β‐d‐ glucopyranosyl‐(1→3)‐O‐[α‐l‐ rhamnopyranosyl‐(1→6)]‐β‐d‐ glucopyranosyl}oxy}‐3,23,24‐trihydroxytirucall‐7‐en‐21‐one ( 3 ), (20S,23R,24S)‐24‐(acetyloxy)‐21,25‐epoxy‐29‐{{O‐β‐d‐ glucopyranosyl‐(1→3)‐O‐[α‐l‐ rhamnopyranosyl‐(1→6)]‐β‐d‐ glucopyranosyl}oxy}‐23‐hydroxytirucall‐7‐ene‐3,21‐dione ( 4 ), and (3β,20S,23R,24S)‐24‐(acetyloxy)‐21,25‐epoxy‐29‐{{O‐β‐d‐ glucopyranosyl‐(1→3)‐O‐[α‐l‐ rhamnopyranosyl‐(1→6)]‐β‐d‐ glucopyranosyl}oxy}‐3,23‐dihydroxytirucall‐7‐en‐21‐one ( 5 ).     

Synthesis of end‐functionalized poly(methyl methacrylate) by ruthenium‐catalyzed living radical polymerization with functionalized initiators

A series of functionalized 2‐bromoisobutyrates and 2‐chloro‐2‐phenylacetates led to α‐end‐functionalized poly(methyl methacrylate)s in Ru(II)‐catalyzed living radical polymerization; the terminal functions included amine, hydroxyl, and amide. These initiators were effective in the presence of additives such as Al(Oi‐Pr)₃ and n‐Bu₃N. The chlorophenylacetate initiators especially coupled with the amine additive gave polymers with well‐controlled molecular weights (M_w/M_n = 1.2–1.3) and high end functionality (F_n ～ 1.0). © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1937–1944, 2002     

Side-chain dynamics of an alpha-helical polypeptide monitored by fluorescence

The "blob" model, developed to analyze the fluorescence decays of polymers randomly labeled with pyrene, has been applied to a series of pyrene-labeled poly(glutamic acid)s (PyPGA) in DMF and carbonated buffer solutions at pH 9. Poly(glutamic acid) (PGA) exists in the ionized form in the buffer solutions as poly(sodium glutamate) (PGNa). PGA adopts an alpha-helical conformation in DMF, whereas in aqueous solution PGNa is a random coil. Fluorescence, UV-vis absorption, and circular dichroism measurements indicate that in our studies pyrene pendants attached themselves along PGA in a clustered manner. Simulations were carried out to establish that the geometry of the PGA alpha-helix induces the high level of pyrene clustering. Since the level of pyrene clustering decreased with lower pyrene content, information about naked PGA was retrieved by extrapolating the trends obtained by fluorescence to zero pyrene content. Analysis of the fluorescence decays demonstrated that during its lifetime an excited pyrene probes a 32 amino acid section of the PGA alpha-helix. This result was supported by molecular mechanics optimizations. This study establishes that the blob model, originally used to monitor the encounters between pyrenes attached randomly onto a polymer adopting a random coil conformation, can also be applied to study the dynamics of the side chains of structured proteins. Since the blob model helps in monitoring the encounters between amino acids in the initial state (i.e., random coil) and in the final state (i.e., structured protein) of the folding pathway of a protein, it could be applicable to the study of protein folding.     

1‐[(5‐tert‐Butyl‐2‐hydroxy­phen­yl)­imino­meth­yl]‐2‐napthol

In the crystal structure of the title compound, C₂₁H₂₁NO₂, strong N—H⋯O and O—H⋯O hydrogen bonds exist. The keto–amine form is favoured over the enol–imine form in the tautomerism. Six‐membered chelate rings formed by intra­molecular hydrogen bonds increase the stability of the whole mol­ecule. Inter­molecular hydrogen bonds link adjacent units together, forming an infinite one‐dimensional chain parallel to the a axis.     

A dimer of α‐ and β‐dihydro­arte­misinin: bis­(3,6,9‐trimethyl‐3,12‐epidioxy‐3,4,5,5a,6,7,8,8a,9,10‐deca­hydro‐12H‐pyrano[4,3‐j][1,2]­benzo­dioxepin‐10‐yl) ether

The title compound, C₃₀H₄₆O₉, prepared from a mixture of α‐ and β‐dihydro­artemisinin, has α‐ and β‐arteether moieties linked via an –O– bridge, so that the mol­ecule is asymmetric about the bridge. The endoperoxide bridges of the parent compounds have been retained in each half of the ether‐bridged dimer. The rings exhibit chair and twist–boat conformations.