Materials Literature
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The synthesis of diarylethyne-linked multiporphyrin arrays requires Pd-mediated coupling conditions that are performed in dilute solution in the absence of copper and that give reaction mixtures that are easily purified. We previously developed copper-free Pd-mediated coupling conditions (Pd 2 (dba) 3 and AsPh 3 in to…
Surface interaction controlled microphase separation leading to the formation of chemically heterogeneous surface nanopatterns in dry ultrathin films of A−B diblock copolymers is studied experimentally and theoretically in the strong segregation limit. On a planar surface one of the blocks (A block) is strongly adsorb…
An antibody−metalloporphyrin assembly that catalyzes the enantioselective oxidation of aromatic sulfides to sulfoxides is presented. Antibody SN37.4 was elicited against a water-soluble tin(IV) porphyrin containing an axial α-naphthoxy ligand. The catalytic assembly comprising antibody SN37.4 and a ruthenium(II) porph…
We studied by neutron reflection the architecture of poly(methyl methacrylate) (PMMA) layers adsorbed on hydroxylated quartz from the melt. The samples were prepared by spin-coating about 1 μ m thick films of PMMA onto quartz plates, annealing at melt conditions for an extended period, and then leaching away unbound m…
In acetonitrile electropolymerization of pyrrole is considerably facilitated by the addition of a small amount of water. Several mechanisms have been suggested in the past to interpret this dramatic influence of water. However, none of them has explained all the experimental results obtained up to now. On the basis of…
The compounds [N(CH(3))(4)][Cu(N(3))(3)] (1) and [N(CH(3))(4)][Mn(N(3))(3)] (2) have been synthesized and characterized. Compound 1 crystallizes in the monoclinic P2(1)/n space group, with Z = 4, a = 7.473(2) Å, b = 15.780(2) Å, c = 9.321(2) Å, and beta = 92.59(2) degrees. Compound 2 crystallizes in the monoclinic P2(…
We have recently shown that nanocomposites of colloidal particles in a fatty lipid matrix can be grown via a diffusion process controlled by selective electrostatic interactions. In this paper, a detailed investigation of the diffusion of carboxylic acid derivatized gold colloidal particles of different sizes into the…
The theory of magnetic symmetry in quasicrystals is used to characterize the nature of magnetic peaks, expected in elastic neutron diffraction experiments. It is established that there is no symmetry-based argument which forbids the existence of quasiperiodic long-range magnetic order. Suggestions are offered as to wh…
Spin tunneling in molecular magnets has attracted much attention, however theoretical considerations of this phenomenon up to now have not taken into account the many-spin nature of molecular magnets. We present, to our knowledge, the first successful attempt of a realistic calculation of tunneling splittings for Mn$_…
Effects of electron correlation in FeSi are studied in terms of the two-band Hubbard model with the density of states obtained from the band calculation. Using the self-consistent second-order perturbation theory combined with the local approximation, the correlation effects are investigated on the density of states a…
Hydrophilic polymer chains, poly(ethylene glycol) (PEG), are attached to glass surfaces by silylation of the silanol groups on glass surfaces with (ω-methoxy-terminated PEG)trimethoxysilanes. We consider these tethered polymer chains to resemble self-assembled monolayers (SAMs) of PEG since the grafting process is ent…
Ultrahydrophobic polypropylene surfaces were prepared by the simultaneous etching of polypropylene and etching/sputtering of poly(tetrafluoroethylene) (PTFE) using inductively coupled radio frequency argon plasma. The semicrystalline polypropylene surface is roughened due to the differential rates at which the crystal…
Metalation of octaethylbilindione (H(3)OEB) with palladium(II) acetate produces the novel tetranuclear complex [Pd(4)(OEB)(2)] in which a (Pd(I)(2))(2+) unit is sandwiched between two helical Pd(OEB) units (see picture). Treatment of [Pd(4)(OEB)(2)] with pyridine/ethanol gives the odd-electron helical complex [Pd(OEB)…
In 2-mm microreactors the activity and selectivity of catalyst library components can be monitored directly by robot-controlled mass spectrometry (the principle setup is shown in the scheme). A maximum of 60 seconds per library component are required.
A blueprint for the design of oxide materials is provided by nature. By borrowing from nature's ability to influence inorganic microstructures in biomineralization processes and in the hydrothermal synthesis of complex minerals, a new class of materials in which organic components exert a role in controlling inorganic…
The cisright harpoon over left harpoon trans photoisomerization of the azobenzene building block 4-(4-aminophenylazo)benzoic acid incorporated in a cyclic peptide (see scheme) facilitated a two-state transition of the peptide chain from a rigid constrained conformation in the trans isomer into the largely free conform…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTPorphyrin Core Star Polymers: Synthesis, Modification, and Implication for Site IsolationStefan Hecht, Henrik Ihre, and Jean M. J. FréchetView Author Information Department of Chemistry, University of California, Berkeley, California 94720-1460 Cite this: J. Am. Chem.…
Potentiodynamic generation of polypyrrole films at an extremely low reaction rate causes the resulting material to show an additional oxidation wave that is more negative and sharper than the one normally observed. The additional peaklike oxidation wave belongs to an unknown structural entity PPy(II). The treatment of…
Eighty isolated channels are present in the array microreactor system that was coupled to a quadrupole mass spectrometer for high-throughput testing of heterogeneous catalyst libraries. The system was used to monitor the activities, selectivities, and reaction kinetics of 66 ternary Pt/Pd/In catalysts for the dehydrog…
Robust hexagonal cavities (dimensions: 17x20x15 Å), encompassed by the pyridyl groups of cyclic metalloporphyrin hexamers (see picture), are the characteristic structural motifs of the nanoporous materials [{M(tpyp)}(6)] small middle dotn G (M=Co, Mn; tpyp=tetrakis(4-pyridyl)porphyrinato; G=guest molecule), which were…