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To study the effect of a stable radical on the photophysical properties of a phosphorescent Pt(II) coordination framework and the intramolecular magnetic interaction between radical ligands in the N^N Pt(II) bisacetylide complexes, we prepared a series of N^N Pt(II) bis(acetylide) complexes with oxoverdazyl radical acetylide ligands. The linker between the Pt(II) center and the spin carrier was systematically varied, to probe the effect on the sign and magnitude of the spin exchange interactions between the radical ligands and photophysical properties. The complexes were studied with steady-state and femtosecond/nanosecond transient absorption spectroscopy, continuous-wave electron paramagnetic resonance (EPR) spectroscopy, and density functional theory (DFT) computations. The transient absorption spectral studies show that the doublet excited state of the radicals are short-lived (τ

We report kinetically controlled chiral supramolecular polymerization based on ligand–metal complex with a 3 : 2 (L : Ag+) stoichiometry accompanying a helical inversion in water. A new family of bipyridine-based ligands (d-L1, l-L1, d-L2, and d-L3) possessing hydrazine and d- or l-alanine moieties at the alkyl chain groups has been designed and synthesized. Interestingly, upon addition of AgNO3 (0.5–1.3 equiv.) to the d-L1 solution, it generated the aggregate I composed of the d-L1AgNO3 complex (d-L1 : Ag+ = 1 : 1) as the kinetic product with a spherical structure. Then, aggregate I (nanoparticle) was transformed into the aggregate II (supramolecular polymer) based on the (d-L1)3Ag2(NO3)2 complex as the thermodynamic product with a fiber structure, which led to the helical inversion from the left-handed (M-type) to the right-handed (P-type) helicity accompanying CD amplification. In contrast, the spherical aggregate I (nanoparticle) composed of the d-L1AgNO3 complex with the left-handed (M-type) helicity formed in the presence of 2.0 equiv. of AgNO3 and was not additionally changed, which indicated that it was the thermodynamic product. The chiral supramolecular polymer based on (d-L1)3Ag2(NO3)2 was produced via a nucleation–elongation mechanism with a cooperative pathway. In thermodynamic study, the standard ΔG° and ΔHe values for the aggregates I and II were calculated using the van't Hoff plot. The enhanced ΔG° value of the aggregate II compared to that of the formation of aggregate I confirms that aggregate II was thermodynamically more stable. In the kinetic study, the influence of concentration of AgNO3 confirmed the initial formation of the aggregate I (nanoparticle), which then evolved to the aggregate II (supramolecular polymer). Thus, the concentration of the (d-L1)3Ag2(NO3)2 complex in the initial state plays a critical role in generating aggregate II (supramolecular polymer). In particular, NO3− acts as a critical linker and accelerator in the transformation from the aggregate I to the aggregate II. This is the first example of a system for a kinetically controlled chiral supramolecular polymer that is formed via multiple steps with coordination structural change., The nanoparticles were transformed into the supramolecular polymer as the thermodynamic product, involving a helical inversion from left-handed to right-handed helicity.

The susceptibility of a water molecule to electric fields provides fundamental and essential information for understanding the vibrational spectra of water clusters and condensed-phase water. In th...

Summary Realizing maximum tumor suppression along with preventing tumor regrowth by optimizing the photon usage in phototherapy remains a major challenge. Herein, a mitochondria-targeted phototheranostic nanoformulation (MsPDTT NPs) was prepared from a molecular theranostic encapsulated into phospholipids. Notably, under single 690 nm laser excitation, MsPDTT NPs can perform dual-mode photoacoustic and near-infrared fluorescence imaging and potent photodynamic therapy/photothermal therapy (PDT/PTT) because of efficient excited-state deactivation pathways (through radiative and energy transfer to generate reactive oxygen species and non-radiative relaxation). The reference RsPDTT NPs lacking the mitochondria-targeting feature exhibit only the PTT property. Based on biological results, the MsPDTT NP therapeutic response can be switched to PDT and PTT under normoxic and hypoxic environments and maximize the overall efficacy of phototherapies without any noticeable side effects. The current findings suggest the potential of using simultaneous PDT/PTT with proper photon utilization as a promising theranostic approach for hypoxic tumor photoablation.

TiO2 photocatalysts have been widely used in the field of renewable energy and environmental clean-up. However, the large band gap of TiO2, along with the fast recombination of charge carriers, significantly lowers the photocatalytic performance. Many strategies have been developed to address this issue, including nanostructuring, introducing oxygen defects, chemical doping, surface sensitization, and employing nanocomposites. Studies of light absorption and especially charge recombination of modified TiO2 particles by experimental approaches are limited by the entangled parameters introduced by experimental conditions. Theoretical approaches have provided useful insight due to the systematic modelling of TiO2 particles. This review encompasses the theoretical approach to investigate the photocatalytic activity of modified TiO2 nanoparticles. The density functional theory (DFT) methods used to describe the properties of TiO2 systems and modelling of the geometric and electronic structure to properly describe the actual nanoparticles used in experiments are discussed. The chemical modification strategies are discussed in terms of band engineering, and charge carrier separation and diffusion in comparison with experimental results. The surface redox reactions are discussed with regard to thermodynamics and kinetics.

Mitochondrial enzyme monoamine oxidase (MAO-A) is known to be overexpressed in prostate cancer (PCa) cells. Herein, we have developed a two-photon probe (PCP-1) for selectively targeting and imaging the MAO-A in PCa. Supported by enzymatic docking and in vitro experiments, PCP-1 showed efficiency to visualize MAO-A overexpressing cells and inhibit their growth and metastasis potential.

In spite of the importance of vibrational Stark effect (VSE) and many attempts, origin of VSE is still unclear in molecular level. Here, we studied on origin of VSE of hydroxyl stretching vibration in small water clusters (monomer, dimer, and tetramer) assuming that VSE can be separated by nuclear and electronic contribution. We calculated total Stark tuning rate (Δμtot) and its nuclear contribution (Δμgeom) using the ab initio method, then the electronic contribution (Δμelec) was simply obtained by the difference, Δμtot – Δμgeom. In all cases, the nuclear contribution has dominant contribution to VSE. The hydroxyl stretching mode with neighboring hydrogen acceptor showed larger Δμgeom than that of dangling bonds. Furthermore, the calculated Δμgeom became larger in larger cluster due to the hydrogen bond network. The comparison between Stark tuning rates including and excluding anharmonicity supports the importance of potential anharmonicity in VSE, as previously reported. Interestingly, a good linear rel...

With the basic research logic stating that the systematic improvement of rural housing plot ′ s boundary barriers should call for the integrated consideration of their on-and-around installing settings, this study tries to analyse characteristics of installing environment of boundary barriers for improvement works of them. Through literature review and then screening process, 3 influencing and appraisal factors were determined: main house-boundary barrier shortest distance as on-site factor, building coverage as inside one, and attached road width as outside one. 21 study villages were subgrouped into structurally improved(9) and not(12). Site investigation and analysis results showed that the relationship between factors has varied very much, i.e. in some cases it is positive or complementary, but in other cases, negative or crossed. Therefore this study would propose that differentiated and flexible strategies with integrated consideration of on-and-around site installing settings be applied in their improvement projects rather than village-wide unified or straight forwarded ones.

In the traditional subsistence farming era in Korea, most of small farmer’s housing plots in the rural villages had their boundary barriers of which materials being the natural ones provided from nearby places. However, during the rapid industrialization period from 1960s, a traditional type of boundary barriers in the rural villages had been replaced mostly by low-cost factory-made ones, which means absolute loss of their amenity values as a linear part of villagescape. In spite of many study efforts on boundary barriers of traditional rural houses, detailed historical dating on them after 1960s have not tried up to now, which provoked to try this study. Through the direct and in-depth interviews to rural villagers sampled from 21 case villages, it was found that original boundary barriers structure in most of farm houses was made of natural materials like stone, soil, trees and bamboo, but, replaced by cement block structures mostly during Saemaeul Project period. However, although being relatively minority, traditional ones have been preserved up to now mainly in remote mountainous and seashore villages, but was in very low condition. In the overall view, for more than half a century, boundary barriers of farm houses had been left without public or private improvement efforts. In order to enhance their amenity values, more research works should be carried out on positive reassessment of the traditional ones harmonized with multifunctionalities for modern village life.

Functional mismatch and thought and plan-less material use of recently built boundary barriers in rural areas should greatly degrade their amenity value as one of linear villagescapes, but, their present state-of-art basically necessary for problem-solving had never surveyed up to now. From this point of view, this study tried to investigate present stock quantities and qualities of boundary barriers in rural areas by sample studies on 21 case villages(7 types 3 cases) and comparative analysis between the planned or improved and nots. Wall type was absolutely dominated in the structural terms, of which more than half was used cement block as building material and, therefore, grey-colored. More than half of total barrier length were fully shielded, while relatively partially shielded in the mountainous villages in open space and `Cultural villages` with closed housing structures. Free standing style of barriers was shown along over two thirds of their total length, although not more than half in planned reclaimed villages. Especially, because of one-sided wall type structure, mismatched over-shieldness and poorer maintenance condition of the boundary barriers in peri-urban villages, there should be provided with very intensive improvement efforts for amenity barriers.