Pyrimidoquinazolinophenanthroline Opens Next Chapter in Design of Bridging Ligands for Artificial Photosynthesis**

The synthesis and detailed characterization of a new Ru polypyridine complex containing a heteroditopic bridging ligand with previously unexplored metal-metal distances is presented. Due to the twisted geometry of the novel ligand, the resultant division of the ligand in two distinct subunits leads to steady state as well as excited state properties of the corresponding mononuclear Ru(II) polypyridine complex resembling those of prototype [Ru(bpy)₃]²⁺ (bpy=2,2'-bipyridine). The localization of the initially optically excited and the nature of the long-lived excited states on the Ru-facing ligand spheres is evaluated by resonance Raman and fs-TA spectroscopy, respectively, and supported by DFT and TDDFT calculations. Coordination of a second metal (Zn or Rh) to the available bis-pyrimidyl-like coordination sphere strongly influences the frontier orbitals, apparent by, for example, luminescence quenching. Thus, the new bridging ligand motif offers electronic properties, which can be adjusted by the nature of the second metal center. Using the heterodinuclear Ru−Rh complex, visible light-driven reduction of NAD⁺ to NADH was achieved, highlighting the potential of this system for photocatalytic applications.     

金属铁络合物光催化二氧化碳还原

二氧化碳(CO₂)光催化还原技术因兼具解决能源和全球变暖问题的潜力而受到关注。金属铁络合物作为分子型催化剂,具有价格低廉、量子效率高、结构可调控和选择性好等优势,表现出优异的CO₂光催化还原性能,成为CO₂光催化还原领域的研究热点。本文综述了近年来基于金属铁络合物光催化二氧化碳还原研究进展。介绍了铁金属络合物(如:铁卟啉、铁多吡啶、五齿铁配合物)CO₂均相光催化还原体系,总结了体系的构成以及作用机理等,着重关注了体系的催化效率和产物的选择性。此外,综述了以半导体纳米材料/量子点作为光敏剂,金属铁络合物作为催化剂的非均相催化体系的研究进展。最后,对该领域未来的研究方向和所面临的挑战做出展望。     

Drug Design—Past,Present, Future

Drug design is a complex pharmaceutical science with a long history. Many achievements have been made in the field of drug design since the end of 19th century, when Emil Fisher suggested that the drug–receptor interaction resembles the key and lock interplay. Gradually, drug design has been transformed into a coherent and well-organized science with a solid theoretical background and practical applications. Now, drug design is the most advanced approach for drug discovery. It utilizes the innovations in science and technology and includes them in its wide-ranging arsenal of methods and tools in order to achieve the main goal: discovery of effective, specific, non-toxic, safe and well-tolerated drugs. Drug design is one of the most intensively developing modern sciences and its progress is accelerated by the implication of artificial intelligence. The present review aims to capture some of the most important milestones in the development of drug design, to outline some of the most used current methods and to sketch the future perspective according to the author’s point of view. Without pretending to cover fully the wide range of drug design topics, the review introduces the reader to the content of Molecules’ Special Issue “Drug Design—Science and Practice”.     

多组件学习器实现有机分子沸点的精准预测

沸点(BP)是有机分子液体的基本物理化学量, 也是化学工业生产中的重要参数. 有机分子的沸点由分子结构决定, 呈现复杂的结构-沸点关系, 函数法(Function Method)、基团贡献法(Group Contribution Method)等传统方法无法应对复杂多样有机分子结构的预测, 应用范围狭窄, 预测精度低. 本研究中, 我们利用基于人工神经网络(ANN)和支持向量机(SVM)的多组件学习器实现有机分子沸点的精准预测. 我们构建了基于可解释性描述符的ANN、基于相关性描述符的ANN及基于复合分子指纹的SVM三个异质模型, 并通过包含4550个各种类别的有机分子沸点的数据集进行训练得到了三个异质性学习器, 最后集成三个学习器对有机分子沸点进行预测. 相比于传统方法和此前的定量结构性质关系(QSPR)模型, 多组件模型结合了三种模型的优点, 展现出很好的预测精度和泛化能力以及低的过拟合, 实现了对多种类型有机分子的沸点的有效预测.     

Probing the Catalytically Active Species in POM-Catalysed DNA-Model Hydrolysis**

Phosphoester hydrolysis is an important chemical step in DNA repair. One archetypal molecular model of phosphoesters is para-nitrophenylphosphate (pNPP). It has been shown previously that the presence of molecular metal oxide [Mo₇O₂₄]⁶⁻ may catalyse the hydrolysis of pNPP through the partial decomposition of polyoxomolybdate framework resulting in a [(PO₄)₂Mo₅O₁₅]⁶⁻ product. Real-time monitoring of the catalytic system using electrospray ionisation mass spectrometry (ESI-MS) provided a glance into the species present in the reaction mixture and identification of potential catalytic candidates. Following up on the obtained spectrometric data, Density Functional Theory (DFT) calculations were carried out to characterise the hypothetical intermediate [Mo₅O₁₅(pNPP)₂(H₂O)₆]⁶⁻ that would be required to form under the hypothesised transformation. Surprisingly, our results point to the dimeric [Mo₂O₈]⁴⁻ anion resulting from the decomposition of [Mo₇O₂₄]⁶⁻ as the active catalytic species involved in the hydrolysis of pNPP rather than the originally assumed {Mo₅O₁₅} species. A similar study was carried out involving the same species but substituting Mo by W. The mechanism involving W species showed a higher barrier and less stable products in agreement with the non-catalytic effect found in experimental results.     

Photoinduced Water Oxidation in Chitosan Nanostructures Containing Covalently Linked RuII Chromophores and Encapsulated Iridium Oxide Nanoparticles

The luminophore Ru(bpy)₂(dcbpy)²⁺ (bpy=2,2’-bipyridine; dcbpy=4,4’-dicarboxy-2,2’-bipyridine) is covalently linked to a chitosan polymer; crosslinking by tripolyphosphate produced Ru-decorated chitosan fibers (NS-RuCh), with a 20 : 1 ratio between chitosan repeating units and Ru^II chromophores. The properties of the Ru^II compound are unperturbed by the chitosan structure, with NS-RuCh exhibiting the typical metal-to-ligand charge-transfer (MLCT) absorption and emission bands of Ru^II complexes. When crosslinks are made in the presence of IrO₂ nanoparticles, such species are encapsulated within the nanofibers, thus generating the IrO₂⊂NS-RuCh system, in which both Ru^II photosensitizers and IrO₂ water oxidation catalysts are within the nanofiber structures. NS-RuCh and IrO₂⊂NS-RuCh have been characterized by dynamic light scattering, scanning electronic microscopy, and energy-dispersive X-ray analysis, which indicated a 2 : 1 ratio between Ru^II chromophores and IrO₂ species. Photochemical water oxidation has been investigated by using IrO₂⊂NS-RuCh as the chromophore/catalyst assembly and persulfate anions as the sacrificial species: photochemical water oxidation yields O₂ with a quantum yield (Φ) of 0.21, definitely higher than the Φ obtained with a similar solution containing separated Ru(bpy)₃²⁺ and IrO₂ nanoparticles (0.05) or with respect to that obtained when using NS-RuCh and “free” IrO₂ nanoparticles (0.10). A fast hole-scavenging process (rate constant, 7×10⁴ s⁻¹) involving the oxidized photosensitizer and the IrO₂ catalyst within the IrO₂⊂NS-RuCh system is behind the improved photochemical quantum yield of IrO₂⊂NS-RuCh.     

State of the art and research development prospects of energy and resource-efficient environmentally safe chemical process systems engineering

In this focus overview, the main types and directions of engineering, methods and techniques of intensification of chemical process systems (CPS) and process optimization of energy- and resource-efficient processes for the representative production of titanium compounds, mining waste processing systems, electrochemical coating technologies, combined technologies for the treatment of industrial effluents and energy-and resource-efficient technologies for cleaning soils from petroleum and chemical pollution products are reviewed. The following issues have been discussed: methods of complex assessment of production energy efficiency and software and information support for automated synthesis of optimal energy-efficient regenerative heat exchange systems using pinch analysis; methods and algorithms for fractal-statistical characteristics analysis of nonstationary gas flows in complex gas pipelines; methods of ecological and economic optimization of production, infrastructure supply chains; methods for assessing and preventing the dangerous environmental impact assessment of chemical pollution; organization and logistics management of business processes engineering for improving the energy efficiency of plants; engineering of problem oriented computer systems, heuristic-computational models and algorithms for intelligent integrated logistics support of the equipment life cycle; engineering developments in the field of digital transformation of energy-efficient CPS and technological production systems; application of methods for optimizing reliability factors optimization, digitalized risk and safety management in the engineering of energy- and resource efficient CPS.     

Mathematical Analysis of Reaction–Diffusion Equations Modeling the Michaelis–Menten Kinetics in a Micro-Disk Biosensor

In this study, we have investigated the mathematical model of an immobilized enzyme system that follows the Michaelis–Menten (MM) kinetics for a micro-disk biosensor. The film reaction model under steady state conditions is transformed into a couple differential equations which are based on dimensionless concentration of hydrogen peroxide with enzyme reaction (H) and substrate (S) within the biosensor. The model is based on a reaction–diffusion equation which contains highly non-linear terms related to MM kinetics of the enzymatic reaction. Further, to calculate the effect of variations in parameters on the dimensionless concentration of substrate and hydrogen peroxide, we have strengthened the computational ability of neural network (NN) architecture by using a backpropagated Levenberg–Marquardt training (LMT) algorithm. NNs–LMT algorithm is a supervised machine learning for which the initial data set is generated by using MATLAB built in function known as “pdex4”. Furthermore, the data set is validated by the processing of the NNs–LMT algorithm to find the approximate solutions for different scenarios and cases of mathematical model of micro-disk biosensors. Absolute errors, curve fitting, error histograms, regression and complexity analysis further validate the accuracy and robustness of the technique.     

蛋白芯片法同时检测食品中克伦特罗与莱克多巴胺的残留量

建立了食品中克伦特罗和莱克多巴胺残留含量同时检测的微阵列蛋白芯片法。结果显示:克伦特罗的线性范围为0.07～1.2 ng/g;莱克多巴胺的线性范围为0.05～0.8 ng/g。猪肉、猪肝中上述两种物质的加标回收率为74%～132%,相对标准偏差均小于10%。将所建立的方法与HPLC-MS方法进行对比,两者检测结果一致。该方法简单、快速、通量高,可用于实际样品中克伦特罗和莱克多巴胺残留量的检测。