Masatoshi Ishida

Abstract A comparison of the kinetic and diffusional models for solid‐gas reactions occurring in a spherical particle is presented. The similarities and differences of the unreacted‐core shrinking model and the homogeneous model are examined in light of the rate‐controlling factors. In view of the similarity of the two models, it is shown that erroneous conclusions in regard to the mechanism and the activation energies may be drawn from an analysis of the experimental data. A more versatile mode

Novel zinc porphyrin dyes for use in dye-sensitized solar cells (DSSCs) have been synthesized. These dyes are based on a molecular design that relies on donor−π–acceptor interactions, a concept implemented by introducing a bis(4-tert-butylphenyl)amino group at the meso position of the porphyrin opposite to what are 2-propenoic or 2,4-pentadienoic acid anchoring groups at the β-pyrrolic positions. Incorporating an electron-donating group (i.e., the diarylamine) on the porphyrin core serves as the

Room for accommodation: A novel porphyrin-related macrocycle was constructed by replacement of the dipyrromethene unit with a 1,10-phenanthroline moiety. This macrocycle is capable of complexation and fluorescent detection of Mg2+ with high selectivity over other physiologically relevant metal ions such as Na+, K+, and Ca2+. It functions well as a fluorescent sensor for Mg2+ even in HEPES buffered aqueous DMSO solution (pH 7.4). Detailed facts of importance to specialist readers are published as

We have investigated the electronic structures and photophysical properties of 5,10,20,25-tetrakis(pentafluorophenyl)-substituted hexaphyrin(1.1.1.1.1.1) (1) and its meso-keto (2) and meso-diketo derivatives (3) using various spectroscopic measurements. In conjunction with theoretical calculations, these analyses revealed fundamental structure-property relationships within this series, including unusual ground-state electronic structures with neutral, monoradical, and singlet biradical character

Stable square planar organocopper(III) complexes (CuNCC2, CuNCC4, and CuBN) supported by carbacorrole-based tetradentate macrocyclic ligands with NNNC coordination cores were synthesized, and their structures were elucidated by spectroscopic means including X-ray crystallographic analysis. On the basis of their distinct planar structures, X-ray absorption/photoelectron spectroscopic features, and temperature-independent diamagnetic nature, these organocopper complexes can be preferably considere

We investigated the detailed photophysical properties of a series of bis-metal (Zn and Cu) dioxohexaphyrin complexes as potential second near-infrared (NIR-II)-light responsive dyes. A <i>cisoid</i>-configured 28π-electron-conjugated dioxohexaphyrin analogue (<i><b>c</b></i><b>-3a</b>) containing two peculiar "confused pyrrole" moieties in the framework is identified as a reduced isomer derivative of a <i>transoid</i> 26π-dioxohexaphyrin (<i><b>t</b></i><b>-2a</b>). The symmetry-altered structur

An expanded metalloporphyrin-based "black dye" Au-Pd oxohexaphyrin (<b>AuPd-1</b>) with absorption capabilities across the visible-to-near-infrared (NIR) range was synthesized. This black dye, <b>AuPd-1</b>, possessed efficient light-harvesting and photostable capabilities, which were indicative of superior photothermal (PT) conversion abilities. Encapsulation of <b>AuPd-1</b> with a micellar nanocapsule resulted in a compound that demonstrated intense photoacoustic (PA) properties in the NIR re

The palladium-catalyzed oxidative alkynylation of β-borylated porphyrins allows for concise preparation of push-pull structured ethynylbenzoic acid porphyrin derivatives. The resulting β-singly- and doubly-substituted porphyrin dyes are regarded as isomeric derivatives of the corresponding meso-substituted reference systems, and were found to give rise to nearly equal power conversion efficiencies when analyzed in DSSCs.

N-fused aza-indacene-based fluorophores 1 and 2 were prepared via a three-component condensation involving benzimidazole-carbinol, trifluoroacetic acid, and either pyrrole or indole, respectively. The N-fused aza-indacenes act as optical-based chemosensors for dissolved carbon dioxide gas following fluoride anion-mediated deprotonation.

Complexation of novel multiply N-confused expanded calix[n]phyrins with boron difluoride afforded a new class of cyclic BODIPY (boron-dipyrromethene) arrays. The structures of circularly arranged BODIPY subunits linked in an N-confused fashion give rise to such photophysical properties unique to the macrocycles as redshifted emission wavelengths along with apparent large Stokes shifts, long emission lifetimes, and solid-state lasing. The DFT calculations support the size-dependent excited-state

A novel [36]octaphyrin analogue embedding two N-confused pyrrole units demonstrated unique prototropy-coupled isomerization between the Figure-of-eight and dumbbell conformers. Upon bis-metal coordination, fixation of fully π-conjugated Figure-of-eight structures was achieved as referred from the X-ray crystal structure. Chirogenesis of the helical enantiomers was proved by intense circular dichroism (CD) response in the near infrared (NIR) region.