Bulletin of the Korean Chemical Society最新文献

The cover image illustrates how repositioning the cyano substitution site between 5-CNI and 6-CNI reshapes the π-electron distribution. Side views of the HOMOs highlight the orbital phase, contrasting the electron density differences at the C5 and C6 positions. Furthermore, the R2PI spectra demonstrate how this single positional change leads to distinct excited-state electronic character. Details are in the article by Ahreum Min, Hakseung Ryu, Jiwon Kim, Cheol Joo Moon, and Myong Yong Choi.

Biomolecules often exhibit non-exponential lifetime distributions in living cells. Chemical dynamics of these biomolecules cannot be described by conventional chemical kinetics or chemical master equations. Here, we present an exact model study to investigate the effects of the nonexponential lifetime distribution on the time-dependent concentration of biomolecules and its steady-state fluctuations. Our exact model study shows that the mean product number increases more rapidly with time as the randomness of the product lifetime decreases even when the mean product creation time and the mean product lifetime are held fixed. The product number fluctuation decreases with product lifetime fluctuation when the product creation is a multi-channel reaction process but increases with product lifetime fluctuation when the product creation is a multi-step reaction process. This work presents a new paradigm of chemical dynamics that accurately describes the time profile and the steady-state fluctuation of biomolecular concentrations in living cells.

Perovskite-based tandem photovoltaics are compelling because they surpass single-junction efficiency limits and deliver higher energy yield per unit area, supporting progress toward lower levelized cost of electricity. However, efficiency alone does not establish technological sustainability, since additional layers, interfaces, and processing routes alter energy and material flows across the product life cycle. Life-cycle assessment (LCA) provides a quantitative framework to evaluate environmental impacts, including greenhouse-gas emissions, toxicity-related indicators, and material criticality, under well-defined functional units and system boundaries. Emerging evidence indicates that perovskite tandems can achieve favorable environmental performance relative to silicon modules when material intensity, manufacturing energy, durability, and circular options such as top-cell renewal and end-of-life recovery are appropriately managed. This review first outlines the working principles, device configurations, and recent LCA findings for perovskite-based tandems. It then presents LCA studies on circular strategies focused on recycling and materials recovery. Finally, it outlines research priorities in LCA and sustainability to support the environmentally responsible development of perovskite photovoltaic technology.

Perovskite-based tandem photovoltaics are compelling because they surpass single-junction efficiency limits and deliver higher energy yield per unit area, supporting progress toward lower levelized cost of electricity. However, efficiency alone does not establish technological sustainability, since additional layers, interfaces, and processing routes alter energy and material flows across the product life cycle. Life-cycle assessment (LCA) provides a quantitative framework to evaluate environmental impacts, including greenhouse-gas emissions, toxicity-related indicators, and material criticality, under well-defined functional units and system boundaries. Emerging evidence indicates that perovskite tandems can achieve favorable environmental performance relative to silicon modules when material intensity, manufacturing energy, durability, and circular options such as top-cell renewal and end-of-life recovery are appropriately managed. This review first outlines the working principles, device configurations, and recent LCA findings for perovskite-based tandems. It then presents LCA studies on circular strategies focused on recycling and materials recovery. Finally, it outlines research priorities in LCA and sustainability to support the environmentally responsible development of perovskite photovoltaic technology.

A novel efficient method provides sustainable synthetic access to multi-substituted cyclopenta[b]indole derivatives is reported. Building upon established synthetic protocols, which often employ noble metal catalysts and demanding conditions, this strategy introduces a molecular designed N-furan aniline for cost-effective and environmentally conscious alternative. The strategy utilizes stoichiometric, readily available aluminum chloride (AlCl₃) under mild conditions, providing broad access to diverse cyclopenta[b]indole derivatives. The proposed mechanism shows that Lewis acid activation triggers a selective ring-opening of the furan, which is crucial for forming the cyclopenta[b]indole framework. The demonstrated synthetic utility, including the facile conversion of the scaffold into diazo and tosylhydrazone derivatives, underscores the potential of this methodology for constructing diverse, complex bioactive molecules, such as those related to Etrasimod and Fischerindole L.

The cover image depicts the formation of chiral metallosupramolecular polymers of a terpyridine-based Pt(II) complex via composition-dependent mechanisms in DMSO/H₂O mixtures. The chirality of the supramolecular polymers depends on the solvent composition, which modulates the energy barrier toward the thermodynamically favored state. Further details are provided in the article by Minju Nam, Sehee Kim, Kayoung Kim, and Jong Hwa Jung.

Mechanochemistry offers a sustainable and efficient alternative to traditional solvothermal methods for advanced porous materials. In particular, it has been widely applied to the synthesis of metal–organic frameworks (MOFs), a representative class of porous materials with high surface area and tunable structures. By applying mechanical force through ball milling or twin-screw extrusion, activation barriers are lowered in the free-energy landscape, enabling rapid bond formation in minutes with minimal or no solvent. Recently, mechanochemistry has gained attention not only for an alternative method for conventional MOF syntheses but also as a way to reach structures and reaction pathways that are difficult to access with traditional methods. In this review, we present four case studies in which mechanochemistry was leveraged to overcome key limitations of MOFs, and we examine how these strategies address those challenges. This review covers four key applications. First, continuous, kilogram-scale production of benchmark MOFs such as UiO-66-NH₂, HKUST-1, and ZIF-8 has been achieved by twin-screw extrusion under water-assisted, solvent-reduced conditions, reaching space–time yields up to 1 × 10⁵ kg m⁻³ day⁻¹. Second, direct mechanochemical routes achieve MOFs inaccessible by solvothermal synthesis, including imine-linked PCN-161 and heterometallic [(PdM)₃(BTC)₄]_n materials in a single milling step. Third, sustainable recycling has been demonstrated by converting PET waste into BDC-based MOFs and by reconstructing hydrolyzed MOF-5, MOF-177, UiO-67, and ZIF-65 into their original structures. Fourth, gentle encapsulation has embedded enzymes in MOF and COF hosts, preserving native activity and conferring resistance to acid and proteases. In each case, tuning milling parameters such as ball size, frequency, milling media, and additive loading controls force magnitude and reaction pathways to direct defect formation, nucleation kinetics, and crystal growth. To further advance the field, truly solvent-free protocols must be developed, scale-up should expand to diverse and complex structures, and deeper mechanistic insight is needed through in situ monitoring and modeling. Integrating mechanochemistry with complementary stimuli and sustainable raw materials will overcome diverse challenges in MOFs, enabling closed-loop lifecycles and paving the way for advanced applications.

A facile one-pot method for preparing amides and esters from benzyl esters has been developed. This study successfully converts benzyl esters into amides and esters using an acid chloride intermediate, facilitated by reactions with α,α-dichlorodiphenylmethane as a chlorinating agent and MoO₃. This approach enables a wide variety of amides and esters to be formed efficiently and in high yields. This synthetic procedure represents a valuable and practical technique for producing amides and esters from benzyl esters.

The gas-phase spectroscopic properties of 6-cyanoindole (6-CNI) were investigated using mass-selected one-color resonant two-photon ionization (R2PI), UV–UV hole-burning, and IR-dip spectroscopy to elucidate its excited-state characteristics. The observed spectra were analyzed with ab initio and density functional theory (DFT) calculations and compared with previously reported results for 5-cyanoindole (5-CNI), providing insight into the structural and electronic variations induced by cyano substitution. The R2PI spectrum exhibited sharp vibronic features in the low-frequency region and pronounced spectral congestion at higher frequencies, indicative of closely spaced excited electronic states. Time-dependent DFT calculations reproduced these spectral trends, confirming the dominant π–π* character of the lowest electronic transitions. A smaller S₁–S₂ energy gap was obtained for 6-CNI (~0.085 eV) compared with that of 5-CNI (~0.11 eV), accounting for the earlier onset of vibronic congestion in 6-CNI. These findings reveal how the position of the cyano substituent modulates the electronic distribution and excited-state dynamics of indole, establishing a foundation for understanding substitution effects in indole-based chromophores.

Hydrogen storage in metal hydrides offers a promising path for scalable and safe hydrogen energy systems. However, high dehydrogenation temperatures, slow kinetics, and energy inefficiencies hinder their widespread adoption. This review assesses recent advancements in dehydrogenation strategies, including thermal, catalytic, mechanical, and microwave-assisted methods, focusing on correlating mechanistic insights with performance metrics. It compiles data on activation energies, onset desorption temperatures, hydrogen release capacities, and cycle stability, highlighting enhancements such as reductions in activation energy from approximately 128.6 kJ/mol in pristine MgH₂ to as low as 45 kJ/mol in engineered composites and hydrogen release rates exceeding 6 wt% within minutes under optimized conditions. The energy efficiencies of advanced techniques often exceed 65%, whereas those of the conventional methods are below 50%. This review identifies critical gaps: (i) the disparity between current dehydrogenation temperatures (170–220°C) and practical targets (<120°C), (ii) insufficient long-term cycling data for assessing durability under real-world conditions, and (iii) challenges in scaling laboratory-based catalytic or microwave-assisted systems to industrial platforms. These insights provide a roadmap for future research, emphasizing the integration of catalytic design, nanostructuring, and hybrid energy inputs to bridge the gap between laboratory advancements and application-ready hydrogen-storage technologies.