Solution State Research Articles

Intraband Exciton Dynamics of n-Doped Silver Selenide Quantum Dots.

AgxSe (x > 2) colloidal quantum dots (CQDs) have recently emerged as a promising environmentally friendly material contender for mid- and long-wave infrared optoelectronics, leveraging their intraband transition (1Se-1Pe). However, multicarrier interactions in CQDs, particularly Auger recombination, have profound implications on the optoelectronic properties of the materials and their potential in device applications. Understanding the intraband excited-state dynamics in n-doped AgxSe is therefore essential for the assessment and successful implementation of this material platform in devices. We, herein, investigate the carrier dynamics of AgxSe in both solution and thin-film states using a femtosecond mid-infrared transient absorption spectrometer. Our observations reveal that the multicarrier Auger process depends on the degree of doping in AgxSe CQDs and accelerates when the Fermi energy (EF) level approaches the 1Pe state. The calculated intraband Auger coefficients (CA) are measured to be on the order of ∼10-28 cm6 s-1, significantly larger compared to analogous n-doped HgS/Se CQDs.

Bridging Frontiers in Macromolecular and Supramolecular Sciences with Living Cationic Ring‐Opening Polymerization of Self‐Organizable Dendronized Cyclic‐Imino Ethers Generating Soft Frank–Kasper and Quasicrystal Arrays

AbstractLiving cationic ring‐opening polymerization accompanied by isomerization of cyclic imino ethers is performed at high temperatures that provide access to the synthesis of self‐organizable systems in their isotropic melt or solution state. This Perspective discusses fundamental mechanistic principles of this polymerization and bridges with the polymerization of dendronized cyclic iminoethers forming polymers that self‐organize soft Frank–Kasper and quasicrystal periodic and quasiperiodic arrays. These two fields represent frontiers in macromolecular and supramolecular science. A brief discussion of the impact of this polymerization on biomaterials and how it impacted contemporary mechanistic investigations is also made. Expected impacts via future synthetic developments and mechanistic investigations are discussed.

The Current Situation of the Housing Market Bubble in Chinas First-tier Cities

Abstract: With the progression of China's economy and urbanization, the real estate industry experienced rapid growth, accompanied by increasing speculative activities, which led to a continuous rise in housing prices and the formation of a bubble. Therefore, the focus of this study was the current state of China's real estate bubble and potential solutions. Given the issue of excessively high real estate prices, this study specifically examined the price trends and factors contributing to the real estate bubble in four Chinese cities: Beijing, Shanghai, Guangzhou, and Shenzhen. The research methodology was as follows: First, data on the price-to-income ratio was collected to analyze the current state of housing prices in China, revealing that housing prices were still far above their actual value and beyond a reasonable range, thereby indicating the severity of the real estate bubble in China. Second, by analyzing data and reviewing the literature, the factors contributing to China's real estate bubble were identified and categorized into two main groups: policy-related and economic. On the policy side, factors included policy reforms, monetary easing, and reductions in both the benchmark interest rate and the reserve requirement ratio. On the economic side, factors included the growth in per capita disposable income and speculative behavior. Finally, this paper analyzed how a property tax could curb speculative activities by increasing the cost of purchasing properties, thereby reducing demand and speculative behavior. The findings revealed that the real estate bubble in China's first-tier cities remained severe, and that a property tax could help curb speculative activities and slow the pace of bubble expansion.

Synthesis of (Z)-Enediynes via Stereoinvertive Nucleophilic Substitution of (E)-Sulfonylethenes with Arylethynide, and Their Aggregation-Induced Optical Properties.

(Z)-Enediynes were successfully synthesized from a trio of terminal ethynes through consecutive three-step reactions: iodosulfonylation of ethyne with I2/PhSO2Na, followed by ethynylations of iodo and sulfonyl moieties of the resulting iodosulfonylethene via Sonogashira-Hagihara coupling and nucleophilic addition-elimination, respectively. The molecular structure of the obtained (Z)-enediyne was fully characterized by X-ray crystal structure analysis, revealing that the nucleophilic substitution of (E)-sulfonylethene with arylethynide underwent a selective stereoinversion. The (Z)-enediynes exhibited photoluminescence in both the solution and solid states (crystals and powders). Ph2N-substituted derivatives showed remarkable solvatofluorochromism, and upon replacing the solvent from toluene to acetonitrile, the emission color changed from blue to yellow.

The Role of Spacers as a Probe in Variation of Photoluminescence Properties of Mono- and Bi-nuclear Boron Compounds.

A series of N,O donor-based mono- and binuclear four-coordinated boron complexes were synthesized. Depending on the substitution and spacer, these complexes exhibit intense blue, green and yellow emission in solution states. Notably, the fluorescence quantum yields (ФF) and fluorescence decay (lifetime, τ) of mononuclear boron complexes (2a-2e) were higher than the binuclear boron complexes (2f-2k). The lowest lifetime and quantum yield in binuclear boron complexes were due to intramolecular rotation induced non radiative processes. The disulphide spacer-based boron complexes2i-2kshowed aggregation-caused quenching in the THF/H2O mixture whereas no other complexes were ACQ responsive. These complexes show large Stokes shift, one of them i.e.2ehas the highest Stokes shift of 130 nm among them. Further, the electrochemical study suggests the presence of two redox incidences. Theoretical studies show close corroboration between the TD-DFT computed and experimentally measured absorption maxima as well as DFT (GIAO) calculated and experimentally measured11B NMR values. This complements the appropriate selection of the theoretical methods to shed light on the electronic transitions in the mono- and binuclear BF2complexes.

The role of presence of wormlike micelles of ionic surfactants on the sterilization efficiency of sodium hypochlorite

Abstract This paper describes an attempt to increase the sterilising efficacy of sodium hypochlorite (SH) by prolonging its shelf life in gel mode through the presence of wormlike micelles. No effect was observed on the presence of SH on the ratio of highest viscosity peak of 20:80 of 3 % (w/w) sodium dodecylsulfate (SDS) and cetyltrimethylammonium bromide (CTAB). On the other side, the presence of SH has a relatively negative effect on transformation process from spherical (three-dimensional, 3D) micelles to wormlike (one-dimensional, 1D) micelles. The gel state of the aqueous SH solution is maintained even at a ratio of 20:80 SDS:CTAB 3 % (w/w). Measurements of the biological activity of the gel using Staphylococcus aureus bacteria show that the sterilizing efficiency of SH is enhanced by the presence of 1D micelles. In contrast, the stability of SH using the kinetic method shows a sudden decrease in its stability due to the presence of 1D micelles, and the same is the case when both SDS and CTAB micelles are present. It was concluded that the increase in the biological activity of SH due to presence of micelles in gel or liquid mode resulted from their chemical interference, which acts as an antibacterial formulation.

Rational design and synthesis of pyrrolo-pyridine dinitrile dyes with strong dual-state emission

In recent years, there has been a growing focus on organic dual-state emission (DSE) materials that demonstrate robust luminescence in both solid and solution states. Nevertheless, in the solid state, π-π stacking between organic molecules often results in pronounced luminescence quenching, posing a significant challenge for the design and synthesis of organic DSE materials. In this work, a pyrrolo-pyridine dinitrile (PPDN) dye was synthesized from commercially available 2-heteroaryl acetonitriles and classical diketopyrrolopyrrole (DPP) dye via a two-step process. Due to its special "J"-shaped planar conjugate structure, the PPDN dye has strong DSE performance, high molar extinction coefficients (ε), large Stokes shifts, and excellent optical and thermal stability. It also has aniline vision detection capability, which is useful in the field of security displays and anti-counterfeiting.

Efficient and White-Light-Like Emission from Nonconventional Luminescent Materials in Solution States

Efficient and White-Light-Like Emission from Nonconventional Luminescent Materials in Solution States

A Fresh Manner Cuckoo Search Algorithm to Hydrothermal Scheduling in Short Term

The main goal of the short-term hydrothermal scheduling (HS) challenge is to drastically reduce the large fuel cost of producing power by scheduling the hydrothermal energy producers while taking power balance restrictions, the reservoir's storage restrictions, the water's gross discharge, and the thermal power generators' and hydropower plants' operating restrictions into account. Many algorithms have been employed to solve this similar problem, and relevant research have been published in the literature; nevertheless, their scope is limited in terms of the number of 16 iterations required to achieve the solution state and the solution state itself. In order to solve the HS problem, this article suggests applying an improved cuckoo search (CS) algorithm known as the fresh manner cuckoo search (FMCS) algorithm, a modified variant of the conventional CS. The suggested FMCS

Deciphering the Conformations of Glutathione Oxidized Peptide: A Comparative NMR Study in Solution and Solid-State Environments.

Glutathione (GSH) and its oxidized dimer (GSSG) play an important role in living systems as an antioxidant, balancing the presence of reactive oxygen species (ROS). The central thiol (-S-S-) bond in GSSG can undergo free rotation, providing multiple conformations with respect to the S-S bridge. The six titratable sites of GSSG, which are influenced by pH variations, affect these conformations in solution, whereas in solids, additionally crystal packing effects come into play. In view of differing reports about the structure of GSSG in literature, we have here conducted an extensive reexamination of its conformations using NMR, and contrasting results have been obtained for solution and solid state. In solution, the existence of more than one antiparallel orientation of the monomer unit with different hydrogen bonding schemes has been indicated by NOE and amide temperature coefficient results. On the other hand, in the solid-state, a 1H-1H double-quantum (DQ) to 13C single-quantum (SQ) correlation study has confirmed a parallel orientation, consistent with the reported X-ray crystal structure. Experimentally assigned solid-state NMR resonances have been validated using GIPAW calculations incorporated in the Quantum ESPRESSO package.

Indonesian mosaic: the essential need for multicultural education

Purpose This desk research critically reviews the existing literature to be dialogued with interviews with several experts on multicultural education in Indonesia to provide input for policymaking and practical strategies. Through a systematic review of academic literature, policy documents and reports, this study aims to provide insights into the challenges and opportunities associated with multicultural education and propose action-based and actionable solutions to promote tolerance, understanding and unity among diverse cultural groups. Design/methodology/approach Using a systematic review methodology, this study analyzed existing literature and involved semi-structured interviews with several experts on multicultural education in Indonesia. By searching academic databases and online repositories, relevant literature was synthesized to generate insights into the current state of multicultural education, key challenges and potential solutions. Thematic analysis identified recurring themes and patterns across the literature, allowing for a nuanced understanding of the complexities surrounding multicultural education in Indonesia. Findings This research highlights the importance of promoting tolerance and unity among diverse cultural groups in Indonesian education, highlighting curriculum reform, teacher training and community engagement, despite institutional barriers and sociocultural prejudices. Practical implications The findings of this study suggest that to maximize the impact of multicultural education in Indonesia, there is a need for comprehensive teacher training programs, equitable resource allocation and localized curricula that reflect Indonesia’s cultural diversity. Policymakers should focus on developing strategies that address the unique challenges of implementing multicultural education in diverse regions, ensuring that all students have access to culturally relevant and inclusive education. Social implications The successful implementation of multicultural education has the potential to promote social harmony and inclusivity in Indonesia by fostering a deeper understanding and appreciation of cultural diversity. Addressing the identified challenges and gaps could lead to more cohesive and tolerant communities, reducing social tensions and conflicts rooted in cultural misunderstandings. This research calls for sustained efforts to ensure that multicultural education becomes a cornerstone of Indonesia’s educational system, contributing to the country’s broader goals of unity in diversity. Originality/value This research contributes to existing literature on multicultural education by synthesizing insights from diverse academic sources. By systematically reviewing literature, this study offers a comprehensive understanding of challenges and opportunities in Indonesia and provides evidence-based recommendations for policymakers, educators and stakeholders. Emphasizing the importance of promoting tolerance and unity, this study offers practical strategies for realizing these goals in Indonesian society.

An anisotropic equation of state for solid solutions, with application to plagioclase

Summary This paper presents a framework for building anisotropic equations of state for solid solutions. The framework satisfies the connections between elastic and thermodynamic properties required by Maxwell’s relations. It builds on a recent anisotropic equation of state for pure phases under small deviatoric stresses, adding a dependence on a vector n, whose components ni contain the molar amounts of independent endmembers in the solid solution. These endmembers may have distinct chemical compositions, site species occupancies or electronic spin states. The high albite-anorthite (C$\bar{\text{1}}$) plagioclase solid solution is used to illustrate the formulation.

Solution State-Like Reactivity of a Flexible Crystalline Werner-Type Metal Complex.

Flexible crystalline solids exhibit unique properties in response to external stimuli like heat and light. However, challenges exist in developing crystalline solids that have similar degrees of flexibility as in solution. Herein, we report the preparation of the new flexible crystalline metal complex [Cd(CF3SO3)2(4-spy)4] (4-spy=4-styrylpyridine), which contains photoreactive 4-spy ligand. Unlike traditional solids, this metal complex displays solution state-like [2+2] photocycloaddition reactivity. Specifically, UV irradiation of the crystalline material leads to formation of the same diverse array of dimers and cis isomer that are generated by photoreaction in the solution state. In addition, the photoresponsive flexibility of the solid leads to a photosalient effect and photo-induced formation of pores. The origin of the solution state-like photoreactivity of the solid is related to properties of the Cd(II) cation and fluorinated CF3SO3 anion, and the multi-orientational arrangement of the 4-spy ligands.

Synthesis and Properties of Tris(3‐Pyrrolyl BODIPY) on 1, 3, 5‐Triazine Scaffold

AbstractTris(3‐pyrrolyl BODIPY) on 1,3,5‐triazine scaffold was synthesized over a sequence of steps starting from commercially available cyanuric chloride. The cyanuric chloride was reacted with p‐hydroxy benzaldehyde to afford 1,3,5‐triazine tris(p‐oxybenzaldehyde) which was then reacted with excess pyrrole under acid catalyzed conditions to afford 1,3,5‐triazine‐tris(meso‐p‐oxyphenyl dipyrromethane). Subsequent in situ oxidation of this compound with DDQ to obtain tris(meso‐oxyphenyldipyrromethene) which was then treated with pyrrole followed by the addition of Et3N/BF3 ⋅ OEt2 afforded fluorescent tris(3‐pyrrolyl BODIPY). For comparison, tris(BODIPY) on the triazine scaffold was prepared by oxidizing tris(meso‐oxyphenyldipyrromethane) with DDQ followed by complexation with BF3 ⋅ OEt2. Both compounds were thoroughly characterized and studied by various experimental and theoretical methods. Absorption, steady state fluorescence, time‐resolved fluorescence, and transient‐absorption studies revealed that in tris(3‐pyrrolyl BODIPY), excitonic interactions between two of the three 3‐pyrrolyl BODIPY units resulted in a hypsochromic shift in spectral bands, reducing the quantum yield and singlet state lifetime whereas tris(BODIPY) did not show such excitonic interactions. DFT studies helped in understanding the excitonic interactions in tris(3‐pyrrolyl BODIPY). The tris(3‐pyrrolyl BODIPY) was fluorescent both in solution and solid state. The viscosity studies indicated that the fluorescence of tris(3‐pyrrolyl BODIPY) increases significantly with solvent viscosity, suggesting its potential for measuring cellular viscosity during physiological processes.

A tale of two old drugs tetracycline and salicylic acid with new perspectives—Coordination chemistry of their Co(II) and Ni(II) complexes, redox activity of Cu(II) complex, and molecular interactions

Extensive use of the broad-spectrum tetracycline antibiotics (TCs) has resulted their wide spread in the environment and drive new microecological balances, including the infamous antibiotic resistance. TCs require metal ions for their antibiotic activity and resistance via interactions with ribosome and tetracycline repressor TetR, respectively, at specific metal-binding sites. Moreover, the Lewis-acidic metal center(s) in metallo-TCs can interact with Lewis-basic moieties of many bioactive secondary metabolites, which in turn may alter their associated chemical equilibria and biological activities. Thus, it is ultimately important to reveal detailed coordination chemistry of metallo-TC complexes. Herein, we report (a) conclusive specific Co2+, Ni2+, and Cu2+-binding of TC revealed by paramagnetic 1H NMR, showing different conformations of the coordination and different metal-binding sites in solution and solid state, (b) significant metal-mediated activity of Cu-TC toward catechol oxidation with different mechanisms by air and H2O2 (i.e., mono- and di-nuclear pathways, respectively), (c) interactions of metallo-TCs with bioactive salicylic acid and its precursor benzoic acid, and (d) noticeable change of TC antibiotic activity by metal and salicylic acid. The results imply that TCs may play broad and versatile roles in maintaining certain equilibria in microecological environments in addition to their well-established antibiotic activity. We hope the results may foster further exploration of previously unknown metal-mediated activities of metallo-TC complexes and other metalloantibiotics.

Stabilization of High-Valent Molecular Cobalt Sites through Oxidized Phosphorus in Reduced Graphene Oxide for Enhanced Oxygen Evolution Catalysis.

Heterogeneous molecular cobalt (Co) sites represent one type of classical catalytic sites for electrochemical oxygen evolution reaction (OER) in alkaline solutions. There are dynamic equilibriums between Co2+, Co3+ and Co4+ states coupling with OH-/H+ interaction before and during the OER event. Since the emergence of Co2+ sites is detrimental to the OER cycle, the stabilization of high-valent Co sites to shift away from the equilibrium becomes critical and is proposed as a new strategy to enhance OER. Herein, phosphorus (P) atoms were doped into reduced graphene oxide to link molecular Co2+ acetylacetonate toward synthesizing a novel heterogeneous molecular catalyst. By increasing the oxidation states of P heteroatoms, the linked Co sites were spontaneously oxidized from 2+ to 3+ states in a KOH solution through OH- ions coupling at an open circuit condition. With excluding the Co2+ sites, the as-derived Co sites with 3+ initial states exhibited intrinsically high OER activity, validating the effectiveness of the strategy of stabilizing high valence Co sites.

Soil health – a perspective

Governments and organizations are expressing growing concerns about soil health, driven largely by uncertainties of food security with an increasing human population and unpredictable effects of climate change. Although considerable literature and debate exist, there is discord around the question, what is a healthy soil? This is not surprising, given the complex roles the soil provides, from the range of food, fiber and medical products, hosting a biodiverse community, and supporting the water and nutrient cycles. While a consensus seems to suggest that a soil in good health should be able to provide goods and services in perpetuity, this does not define soil health, rather its provisioning functions. To explore the question, ‘what is healthy?’, we propose an analogy comparing indicators of human and soil health. For example, to identify the cause of a symptom, we compare the diagnostic pH in both humans and soil, demonstrating the similarities between the way human and soil health concerns are addressed. Additionally, we consider the context that necessitates health and use a set of holistic predictors to link human and soil health further. In humans, genetics express many traits and can predispose one to certain illnesses or diseases, in the same way, parent material, soil texture, and length of time exposed to weathering can inform a soil’s capability and predisposition for certain habitats or uses. In both cases, science informs the state of health and appropriate management solutions. We posit the null hypothesis “the concept of human health cannot be applied to soil”.

Switching from Molecules to Functional Materials: Breakthroughs in Photochromism With MOFs.

Photochromic materials with properties that can be dynamically tailored as a function of external stimuli are a rapidly expanding field driven by applications in areas ranging from molecular computing, nanotechnology, or photopharmacology to programable heterogeneous catalysis. Challenges arise, however, when translating the rapid, solution-like response of stimuli-responsive moieties to solid-state materials due to the intermolecular interactions imposed through close molecular packing in bulk solids. As a result, the integration of photochromic compounds into synthetically programable porous matrices, such as metal-organic frameworks (MOFs), has come to the forefront as an emerging strategy for photochromic material development. This review highlights how the core principles of reticular chemistry (on the example of MOFs) play a critical role in the photochromic material performance, surpassing the limitations previously observed in solution or solid state. The symbiotic relationship between photoresponsive compounds and porous frameworks with a focus on how reticular synthesis creates avenues toward tailorable photoisomerization kinetics, directional energy and charge transfer, switchable gas sorption, and synergistic chromophore communication is discussed. This review not only focuses on the recent cutting-edge advancements in photochromic material development, but also highlights novel, vital-to-pursue pathways for multifaceted functional materials in the realms of energy, technology, and biomedicine.

New AIEgens based on thieno[2,3-d]pyrimidine derivatives: Synthesis, DFT calculations, and molecular docking

In this paper, new thieno[2,3-d]pyrimidine analogs have been synthesized and characterized through different spectroscopic techniques. The photophysical properties of the molecules (7b-7f) and the quantum chemical calculations have been investigated. These molecules exhibited aggregation-induced emission behavior and showed efficient emission in both solid and solution states. A shift toward shorter wavelengths (hypsochromic shift) was observed when transitioning from the solution to the solid state, which could be explained by photoinduced intramolecular charge transfer (ICT) processes. DFT calculations confirmed that the diverse behavior of the thieno[2,3-d]pyrimidine analogs could be attributed to variations in molecular packing and rigidity. This study illustrates how luminophores aggregation can occur without significantly impacting the excited state, emphasizing the unconventional behavior resulting from minor alterations in terminal substituents. These findings hold implications for the advancement of luminescent materials. Additionally, theoretical calculations were conducted to compare the excitations and emissions of the new AIEgens with practical observations. Furthermore, a molecular docking study of the five AIEgens suggested their potential utility as anticancer drugs. Compound 7c exhibited a high affinity for human cyclin-dependent kinase 2 (CDK-2) protein, with a binding energy of 9.6 kcal/mol, indicating its potential as an inhibitor for this specific protein.

Luminescent Bis(amidinate) Indium Complexes.

Bis-amidinate indium(III) monochlorides [(tBuN)2C(Ph)]2InCl (1), [(tBuN)2C(2-naphthyl)]2InCl (2), [(tBuN)2C(2-anthryl)]2InCl (3), [(tBuN)2C(9-anthryl)]2InCl (4), [(tBuN)2C(9-phenanthryl)]2InCl (5), and [(tBuN)2C(1-pyrene)]2InCl (6) were prepared by the reaction of the corresponding Li-amidinate ligand with InCl3. Single crystal X-ray analysis of compounds 1, 2, 4, and 5 reveals that the In(III) center is bound with two chelating amidinate ligands. The overall coordination geometry around In(III) is distorted trigonal bipyramidal with the chloride occupying one of the equatorial positions. The photophysical properties of these compounds have been analyzed. Compounds 2-6 are emissive in the solution state. The 9-anthryl substituted compound 4 was found to exhibit a maximum quantum yield of 45.5% in dichloromethane. Compound 3 has a maximum lifetime of 11 ns in solution. Theoretical studies were performed to validate the photophysical properties observed in these compounds.