Materials Literature
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Abstract We have prepared new polyesters containing quadratic, nonlinear optical (NLO) active chromophores covalently incorporated into the main chain. In these polymers, the sequence of the chromophore units along the main chain is rigorously head to tail. All the polyesters are processable, both in the melt and in s…
We investigated the structures of a series of glutathionate-protected gold clusters, Au n (SG) m with n = 10−45, using 197 Au Mössbauer spectroscopy, which allows us to probe the local environment of the Au sites via isomer shift (IS) and quadrupole splitting (QS). The spectral analysis, with the help of recent theore…
Beta-amino-meso-tetraarylporphyrins react with cyclic enol ethers to yield pyrido[2,3-b]porphyrins bearing two vicinal hydroxyalkyl groups. These reactions are catalyzed by lanthanum triflate and occur under mild conditions. Esterification of the hydroxyalkyl groups with succinic anhydride and dodecanoyl chloride affo…
A new kind of functionalized Janus dendrimer has been synthesized via a liquid-phase approach, which could easily be purified using a simple precipitation method without the need for chromatographic separation. Their use for liquid-phase organic synthesis has been achieved in the Pd-catalyzed Suzuki coupling reactions…
O $K$-edge x-ray absorption near-edge structure (XANES) spectra of $\ensuremath{\alpha}$-quartz-type and rutile-type $\mathrm{Ge}{\mathrm{O}}_{2}$ polymorphs and of ${\mathrm{K}}_{2}{\mathrm{Ge}}_{8}{\mathrm{O}}_{17}$ have been analyzed using first-principles plane-wave pseudopotential calculations. XANES spectra have…
Abstract Differential scanning calorimetry (DSC) of triple blends of high molecular weight poly( N ‐vinyl pyrrolidone) (PVP) with oligomeric poly(ethylene glycol) (PEG) of molecular weight 400 g/mol and copolymer of methacrylic acid with ethylacrylate (PMAA‐ co ‐EA) demonstrates partial miscibility of polymer componen…
Secondary active-site residues in enzymes, including hydrophobic amino acids, may contribute to catalysis through critical interactions that position the reacting molecule, organize hydrogen-bonding residues, and define the electrostatic environment of the active site. To ascertain the tolerance of an important model…
We present a scenario for the peculiar coexistence of charge fluctuations observed in quasi-2D 1/4-filled organic conductors theta-(BEDT-TTF)2X in the quantum critical regime where the charge ordering is suppressed down to zero temperature. The scenario is explored in the extended Hubbard model including electron-phon…
Hyperbranching poly(allylamine) (PAAm) and poly(ethylene glycol) (PEG) on silicon and its effect on protein adhesion was investigated. Hyperbranching involves sequential grafting of polymers on a surface with one of the components having multiple reactive sites. In this research, PAAm provided multiple amines for graf…
The structural and magnetic properties of ${\mathrm{Dy}}_{2}{\mathrm{Fe}}_{17\ensuremath{-}x}{\mathrm{Mn}}_{x}$ $(x=0--5)$ compounds have been investigated using x-ray diffraction, linear thermal expansion, magnetization measurements, and $^{57}\mathrm{Fe}$ M\"ossbauer spectroscopy. Compared with ${\mathrm{Dy}}_{2}{\m…
A mechanism accounting for the photochromic properties of dimethyldihydropyrene (DHP)/metacyclophanediene (CPD) is proposed based on high-level CASSCF/CASPT2 ab initio calculations. The very low ring-opening quantum yield observed upon irradiation of DHP is explained by the quenching of the photoisomerization channel…
We report that a twisting deformation mode emerges with the rippling in bent multiwalled carbon nanotubes via atomistic simulations. This mode arises from the curvature-induced lattice mismatch, and is energetically favorable. For the nanotubes with larger radii, twisting may enhance the local strain relaxation. Under…
Abstract Novel halogen‐free compounds [9,10‐dihydro‐9‐oxa‐10‐phosphaphanthrene‐10‐oxide/vinyl methyl dimethoxysilane/ N ‐β‐(aminoethyl)‐γ‐aminopropyl methyl dimethoxysilane (DOPO–VMDMS–NMDMS)] that simultaneously contain phosphorus, nitrogen, and silicon have been synthesized through the reaction of 9,10‐dihydro‐9‐oxa…
The crystallinity and porosity of all-inorganic dodecatungstophosphate M3PW12O40 (M=Cs, NH4, Ag, denoted as MPW) particles are controlled by the changes in the synthetic temperatures and countercations. The MPW particles can be classified into three groups by the crystallinity and porosity: (i) mesoporous "disordered"…
Rapid-injection NMR experiments with 2-cyclohexenone, TMSCl, and Me 2 CuLi•LiCN by the Bertz and Ogle team (Bertz, S. H.; Cope, S.; Murphy, M.; Ogle, C. A.; Taylor, B. J. J. Am. Chem. Soc. 2007, 129, 7208−7209) have led to the observation of a new product-forming conjugate addition intermediate characterized by 1 H an…
Ab initio density functional theory (DFT) calculations are performed to study the formation and diffusion of hydrogen vacancies on MgH 2 (110) surface and in bulk. We find that the formation energies for a single H-vacancy increase slightly from the surface to deep layers. The energies for creating adjacent surface di…
A novel amphiphilic water-soluble 2PA-chromophore-containing block copolymer was designed and synthesized. Micelles (nanostructures) were generated in the aqueous solution using the block copolymer and characterized using dynamic light scattering (DLS) and atomic force microscopy (AFM). We demonstrated that hydrophobi…
Aminyl diradical, which is stable in solution at low temperatures, is prepared. EPR spectra and SQUID magnetometry indicate that the diradical is planar and it possesses triplet ground state, with strong ferromagnetic coupling.
Piezoresponse force microscopy (PFM) has emerged as a primary tool for imaging, domain engineering, and switching spectroscopy on ferroelectric materials. Quantitative interpretation of PFM data, including measurements of the intrinsic width of the domain walls, determination of geometric parameters of the domain belo…
Among the large Au n - clusters for n > 20, the photoelectron spectra of Au 34 - exhibit the largest energy gap (0.94 eV) with well-resolved spectral features, making it a good candidate for structural consideration in conjunction with theoretical studies. Extensive structural searches at several levels of density fun…