Direct perfluoroalkylation of non-activated aromatic C-H bonds of phenols

A simple procedure for the perfluoroalkylation of the aromatic ring of phenols under mildly basic conditions is described. Treatment of a variety of phenols with perfluoroalkyl iodide in the presence of the radical initiator V-70L and Cs₂CO₃ provided the corresponding perfluoroalkylated products in moderate to good yields. Generally, the reaction proceeded smoothly at room temperature to yield regioselectively perfluoroalkylated products.     

Surrogate analysis for detecting nonlinear dynamics in normal vowels.

Normal vowels are known to have irregularities in the pitch-to-pitch variation which is quite important for speech signals to be perceived as natural human sound. Such pitch-to-pitch variation of vowels is studied in the light of nonlinear dynamics. For the analysis, five normal vowels recorded from three male and two female subjects are exploited, where the vowel signals are shown to have normal levels of the pitch-to-pitch variation. First, by the false nearest-neighbor analysis, nonlinear dynamics of the vowels are shown to be well analyzed by using a relatively low-dimensional reconstructing dimension of 4 < or = d < or = 7. Then, we further studied nonlinear dynamics of the vowels by spike-and-wave surrogate analysis. The results imply that there exists nonlinear dynamical correlation between one pitch-waveform pattern to another in the vowel signals. On the basis of the analysis results, applicability of the nonlinear prediction technique to vowel synthesis is discussed.     

Topological factors governing the HOMO-LUMO band gap of the density of states of periodic hydrocarbon polymer networks

The band structures and density of states of 77 infintely large conjugated hydrocarbon polymer networks are calculated with HMO. A general rule for predicting whether the HOMO-LUMO band gap is zero or non-zero is proposed for an arbitrary hydrocarbon polymer network with periodic structure. The effects of bond alternation and of conjugate branching are discussed. Molecular design of high spin polymer networks is proposed.     

Cyanurate-guided self-assembly of a melamine-capped oligo(p-phenylenevinylene)

An oligo(p-phenylenevinylene) capped on one end by a monotopic DAD-type triple hydrogen-bonding module shows distinct optical properties as well as self-organization behavior upon complexation with cyanurates with different numbers of ADA-type triple hydrogen-bonding sites.     

Data synchronization in a network of coupled phase oscillators

We devised a new method of data mining for a large-scale database. In the method, a network of locally coupled phase oscillators subject to Kuramoto's model substitutes for given multivariate data to generate major features through phase locking of the oscillators, i.e., phase transition of the data set. We applied the method to the national database of care needs certification for the Japanese public long-term care insurance program, and found three major patterns in the aging process of the frail elderly. This work revealed the latent utility of Kuramoto's model for data processing.     

Surface modification of gold nanorods with synthetic cationic lipids

Colloidal gold nanorods (GNRs), which were passivated with cationic cerasome-forming lipids having triethoxysilyl groups, were obtained in the aqueous phase by sonication of the mixture of lipids and GNRs.     

Self‐Alignment of Low‐Valent Octanuclear Palladium Atoms

A linear tetraphosphine, meso‐bis[(diphenylphosphinomethyl)phenylphosphino]methane (dpmppm) was used to synthesize linear octapalladium‐extended metal atom chains as discrete molecules of [Pd₈(μ‐dpmppm)₄](BF₄)₄ ( 1 ) and [Pd₈(μ‐dpmppm)₄L₂](BF₄)₄ (L=2,6‐xylyl isocyanide (XylNC; 2 ), acetonitrile ( 3 ), and N,N‐dimethylformamide (dmf; 4 )), which are stable in the solution states and show interesting temperature‐dependent photochemical properties in the near IR region. Variable temperature NMR studies demonstrated that at higher temperature T≈140 °C the Pd₈ chains were dissociated into Pd₄ fragments, which were thermodynamically self‐aligned to restore the Pd₈ chains at lower temperature T<60 °C. The coldspray ionization mass spectra suggested a possibility for further aggregation of the linear tetrapalladium units.     

Linear polystyrene-stabilized palladium nanoparticles-catalyzed C-C coupling reaction in water

Linear polystyrene-stabilized PdO nanoparticles (PS-PdONPs) were prepared in water by thermal decomposition of Pd(OAc)(2) in the presence of polystyrene. The immobilization degree of palladium was dependent on the molecular weight of polystyrene, while the size of the Pd nanoparticles was not. Linear polystyrene-stabilized Pd nanoparticles (PS-PdNPs) were also prepared using NaBH(4) and phenylboronic acid as reductants. The catalytic activity of PS-PdONPs was slightly higher than that of PS-PdNPs for Suzuki coupling reaction in water. PS-PdONPs exhibited high catalytic activity for Suzuki and copper-free Sonogashira coupling reactions in water and recycled without loss of activity.