Design and synthesis of a diverse morpholine template library

Efficient and general procedures have been developed for the solution-phase preparation of substituted morpholine derivatives, and a library has been produced around generic structure 1. This library was designed with proprietary modeling software for use as a general screening library. The 30 R1 reagents were phenols, and the 275 R2 reagents were taken from five different reagent classes, giving a variety of product classes in the final library of 8250 potential products. All of the library members were generated from a common intermediate, mesylate (5), which was synthesized efficiently, in bulk, in three steps from N-benzylethanolamine (2). High-throughput chemistry using robotics was carried out to produce the 7907 library members, which were individually characterized by reversed-phase LC/MS analysis.     

Synthesis of macrocyclic ligands containing the indole ring system

2,7-Diformyl-3-methyl-4,6-dimethoxyindole (6) has been synthesized and converted by metal template reactions into the macrocyclic complexes (10–12).     

The dynamical motion of atoms at the Ni(111) surface

One atom phonon spectral densities are presented for the vibrations of atoms at the Ni(111) surface both parallel and perpendicular to the surface. They are also presented for perpendicular motion of an adsorbed oxygen atom and the nickel atom immediately below it. The results are obtained using a continued fraction technique. They are compared with recent EELS data obtained by Ibach and Bruchmann.     

In situ single-crystal X-ray diffraction studies of desorption and sorption in a flexible nanoporous molecular framework material

The subtle flexibility of the framework material Co(bpy)1.5(NO3)2.(guest) (bpy = 4,4'-bipyridine) (1.(guest)) is demonstrated quantitatively through in situ single-crystal X-ray diffraction measurements of guest desorption and sorption processes. Variable temperature unit cell determinations were employed to monitor the uptake and release of guest species, and full structural determinations have been carried out for the as-grown ethanol-loaded framework (1.(EtOH)), for the empty host framework, and for each of the five introduced guests (methanol: 1.(MeOH), acetone: 1.(ACN), acetonitrile: 1.(MeCN), tetrahydrofuran:1.(THF), dichloromethane: 1.(DCM)). The framework consists of interdigitated two-dimensional bilayers of cobalt(II) centers bridged by bpy ligands, with one-dimensional pores that account for approximately 20% of the total volume. The sorption of guest species of varying size and shape has revealed the framework's ability to adapt to different guests through a range of different framework flexibilities.     

Oxidation reactions of an anionic gallium(I) N-heterocyclic carbene analogue with group 16 compounds

The reactivity of an anionic gallium(I) heterocycle, [K(tmeda)][:Ga([N(Ar)C(H)]2)], Ar = C6H3Pr(i)2-2,6, towards sources of elemental chalcogens and diorgano-dichalcogenides has been investigated and comparisons drawn with the reactivity of the valence isoelectronic N-heterocyclic carbene class of ligand. The reactions of the heterocycle with N2O or (Te)PEt3 yielded the dimeric, dianionic gallium(III) complexes, [K(L)]2[(mu-E)Ga([N(Ar)C(H)]2)]2, E = O, L = tmeda; E = Te, L = THF. Treatment of [K(tmeda)][:Ga([N(Ar)C(H)]2)] with the diphenyl dichalcogenides, PhEEPh, E = Se or Te, gave the one dimensional polymer, [K[(PhSe)2Ga([N(Ar)C(H)]2)]]infinity and the monomeric complex, [K(OEt2)3][(PhTe)2Ga([N(Ar)C(H)]2)], respectively. The X-ray crystal structures of the four complexes are reported.     

Puroindoline-a, a lipid binding protein from common wheat, spontaneously forms prolate protein micelles in solution

The self-assembly in solution of puroindoline-a (Pin-a), an amphiphilic lipid binding protein from common wheat, was investigated by small angle neutron scattering, dynamic light scattering and size exclusion chromatography. Pin-a was found to form monodisperse prolate ellipsoidal micelles with a major axial radius of 112 ± 4.5 ? and minor axial radius of 40.4 ± 0.18 ?. These protein micelles were formed by the spontaneous self-assembly of 38 Pin-a molecules in solution and were stable over a wide pH range (3.5-11) and at elevated temperatures (20-65 °C). Pin-a micelles could be disrupted upon addition of the non-ionic surfactant dodecyl-β-maltoside, suggesting that the protein self-assembly is driven by hydrophobic forces, consisting of intermolecular interactions between Trp residues located within a well-defined Trp-rich domain of Pin-a.     

Laser flash photolysis of diphenylsulfonyldiazomethane: detection of the sulfene and a sulfene-pyridine ylide

The photochemistry of diphenylsulfonyldiazomethane (DSD) was studied by means of nanosecond laser flash photolysis. The photochemical behavior of this molecule upon UV irradiation is characterized by sulfene formation, presumed to arise via Wolff rearrangement of a carbene. We were able to detect the sulfene and the sulfene ylide formed upon sulfene trapping by pyridine. Sulfene quenching by nucleophiles was also examined.     

Laser flash photolysis of 2-diazo-1,3-diphenyl-1,3-propanedione: An unusual long-lived triplet as a reaction intermediate

Laser flash photolysis of 2-diazo-1,3-diphenyl-1,3-propanedione (DBD) is presumed to involve a short-lived carbene, followed by Wolff rearrangement to a long-lived ketene. We have detected ketene ylides following photolysis of DBD in the presence of amines but not with pyridine. The triplet state of DBD lives several microseconds, an unusual observation for a diazo compound; however, the triplet is not a ketene precursor, which must result from excited singlet state fragmentation of DBD.     

Synthesis of perfluorinated functionalized, branched ethers

We wish to report synthesis of perfluorinated functionalized, branched ethers from their hydrocarbon analogues by direct fluorination. Yields up to 90%, with high purities, have been obtained at ambient temperature and pressure. This technique will likely develop into a new general method for producing perfluorinated, hyperbranched and dendritic polymers.