Anion-directed formation and degradation of an interlocked metallohelicate

Although there are many examples of catenanes, those of more complex mechanically interlocked molecular architectures are rare. Additionally, little attention has been paid to the degradation of such interlocked systems into their starting complexes, although formation and degradation are complementary phenomena and are equally important. Interlocked metallohelicate, [(Pd(2)L(4))(2)](8+) (2(8+)), is a quadruply interlocked molecular architecture consisting of two mechanically interlocked monomers, [Pd(2)L(4)](4+) (1(4+)). 2(8+) has three internal cavities, each of which encapsulates one NO(3)(-) ion (1:3 host-guest complex, 2?(NO(3)|NO(3)|NO(3))(5+)) and is characterized by unusual thermodynamic stability. However, both the driving force for the dimerization and the origin of the thermodynamic stability remain unclear. To clarify these issues, BF(4)(-), PF(6)(-), and OTf(-) have been used to demonstrate that the dimerization is driven by the anion template effect. Interestingly, the stability of 2(8+) strongly depends on the encapsulated anions (2?(NO(3)|NO(3)|NO(3))(5+) ? 2?(BF(4)|BF(4)|BF(4))(5+)). The origins of this differing thermodynamic stability have been shown through detailed investigations to be due to the differences in the stabilization of the interlocked structure by the host-guest interaction and the size of the anion. We have found that 2-naphthalenesulfonate (ONs(-)) induces the monomerization of 2?(NO(3)|NO(3)|NO(3))(5+) via intermediate 2?(ONs|NO(3)|ONs)(5+), which is formed by anion exchange. On the basis of this finding, and using p-toluenesulfonate (OTs(-)), the physical separation of 2?(NO(3)|NO(3)|NO(3))(5+) and 1(4+) as OTs(-) salt was accomplished.     

Chronological Change from Face‐On to Edge‐On Ordering of Zinc–Tetraphenylporphyrin at the Phenyloctane–Highly Oriented Pyrolytic Graphite Interface

The self‐assembled structure of alkoxy‐ and N‐alkylcarbamoyl‐substituted zinc–tetraphenylporphyrin at the liquid–highly oriented pyrolytic graphite (HOPG) interface was observed by using scanning tunneling microscopy. The alkoxy porphyrin showed a phase transition from face‐on to edge‐on ordering. The phase transition requires the close‐packed structure of alkoxy porphyrin. The chronological change of the ordering was traced to show the existence of several types of Ostwald ripening including two‐step phase transition from small edge‐on to face‐on and then further to edge‐on orderings. On the other hand, the N‐alkylcarbamoyl porphyrin showed persistent edge‐on ordering, and the ordering was analyzed by the Moiré pattern. Although the edge‐on ordering is observed only in the nonpolar solvent, the orderings have potential applications in the charge and energy transfer.     

Phase-crossing algorithm for white-light fringes analysis

The phase-crossing algorithm is proposed for white-light interferometry, which uses the multi-color phase information of spectrally decomposed interferograms recorded simultaneously with color-sensitive image sensors. The location of zero optical path difference is identified as the singular point at which the phase becomes color invariant, and is determined accurately with a sub-sampling-interval resolution from the crossing point of the multi-color phase distributions obtained by the Fourier transform method. An experimental result is presented that demonstrates the performance of the phase-crossing algorithm.     

Gradient-Based Blind Deconvolution with Phase Spectral Constraints

This paper proposes a new blind deconvolution method with additional phase spectral constraints for a blurred image. A degradation of an original image is mathematically modeled by a convolution of an original image and a point-spread function (PSF). The proposed method consists of the following three steps: (i) projection onto a complex set satisfying the phase spectral constraint in a frequency space; (ii) minimization of a cost function preserving the constrained phase spectra; and (iii) projection onto an image space satisfying nonnegative and support constraints. This method restores both the original image and the PSF with high accuracy. The effectiveness of the proposed method is verified by applying it to some blind deconvolution problems for digital images, and the experimental results show that the performance is superior to the conventional blind deconvolution methods.     

Monodromy at Infinity and the Weights of Cohomology

We show that for a polynomial map, the size of the Jordan blocks for the eigenvalue 1 of the monodromy at infinity is bounded by the multiplicity of the reduced divisor at infinity of a good compactification of a general fiber. The existence of such Jordan blocks is related to global invariant cycles of the graded pieces of the weight filtration. These imply some applications to period integrals. We also show that such a Jordan block of size greater than 1 for the graded pieces of the weight filtration is the restriction of a strictly larger Jordan block for the total cohomology group. If there are no singularities at infinity, we have a more precise statement on the monodromy.     

Effect of “topotactic” reduction product of molybdenum disulfide on catalytic activity of metallocene catalyst for olefin polymerization

N,N-Dimethylanilinium salt of molybdenum disulfide (MoS₂) was developed as a novel cocatalyst for metallocene catalysts. The cocatalyst is composed of N,N-dimethylanilinium ion as a cationic part and “topotactic” reduction product of MoS₂, obtained by acquisition of an electron by neutral host lattice of MoS₂ without structural alteration, as an anionic part. In ethylene polymerization, addition of the N,N-dimethylanilinium salt of MoS₂ to the bis(indenyl)zirconium dichloride (Ind₂ZrCl₂)/triethylaluminum (Et₃Al) catalyst improved the catalytic activity per mmol of Ind₂ZrCl₂. The catalytic activity of this system activated by addition of the cocatalyst depended significantly on the amount of the cocatalyst and the N,N-dimethylanilinium ion content in the cocatalyst. Poly(ethylene) and poly(ethylene-co-1-hexene) obtained with the metallocene catalyst activated by addition of the cocatalyst have typical features such as narrow molecular weight distribution and narrow composition distribution like polymers obtained with conventional metallocene catalysts.     

Randomly-grown high-dielectric-constant ZnO nanorods for?near-field enhanced Raman scattering

We investigate the dependence of the size parameter in the Mie scattering theory on the near-field enhanced Raman scattering properties for high dielectric constant ZnO nanorods grown randomly by PLD (pulsed laser deposition). High Raman signals of Rhodamine 6G (R6G) at 532 nm excitation wavelength were observed with nanorods of 400 nm average diameter. This experimental result was explained theoretically by the size parameter described in the Mie scattering theory, not by surface plasmon polaritons. This was also confirmed by the near-field distribution calculated by the FDTD (Finite-Difference Time Domain) method. The ZnO nanorods with 400 nm average diameter can detect as low as 1 μM of R6G. This near-field enhancement factor is equivalent to that with 10-nm-thick gold-coated ZnO nanorods (nanoshells) with an average core diameter of 100 nm. Controlling the diameter of bare ZnO nanorods is effective for obtaining large enhancement factors without an additional process of gold thin film coating on them.     

Image super-resolution based on local self-similarity

A new image super-resolution method based on a codebook mapping is proposed. The codebook mapping represents the internal relationship between low-and high-frequency image components, and is used for the estimation of highfrequency image components lost in the sampling process. In the proposed method, codebooks are first generated by the low-and high-frequency image components of the original image itself that is to be processed. Then, a resultant superresolution image, that is, an enlarged image, is obtained by combining the estimated high-frequency image components with the low-frequency ones obtained by a typical interpolation-based method. The effectiveness of the proposed method is verified by comparing it against some conventional methods.