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Selective synthesis of the B_(11)H_(14)^(-) and B_(12)H_(12)^(2-) borane derivatives and the general mechanisms of the B-H bond condensation

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Science China Chemistry 2024年第3期67卷 876-881页

作者： Yi Jing Xinghua Wang Hui Han Xin-Ran Liu Xing-Chao Yu Xi-Meng Chen Donghui Wei Lai-Sheng Wang Xuenian Chen College of Chemistry Green Catalysis CenterZhengzhou UniversityZhengzhou 450001China School of Chemistry and Chemical Engineering Henan Key Laboratory of Boron Chemistry and Advanced Energy MaterialsHenan Normal UniversityXinxiang 453007China Department of Chemistry Brown UniversityProvidenceRI 02912USA

Polyhedral boranes are a class of well-known boron molecular clusters with unique physical and chemical properties,and great efforts have been made in the past decades to find more effective synthetic methods.However,the established synthetic methods suffer from low efficiency and low selectivity because the mechanism of the B-H bond condensation reaction,critical for the synthesis of the polyhedral boranes,is not well understood.Here we report highly selective and efficient synthetic methods of the salts of the tetradecahydridoundecaborate(1-)(B_(11)H^(-)_(14)) and dodecahydrido-dodecaborates(2-)(B_(12)H_(12)^(2-)) anions by employing commercially available and inexpensive starting materials.Both theoretical and experimental investigations are carried out to elucidate the reaction mechanisms.We have found that the nature of the B-H bond condensation is the dihydrogen bonding interaction in which the positively charged hydrogens(bridged hydrogens) play a crucial role.The current study has not only led to more effective and selective synthetic methods for B_(11)H^(-)_(14) and B_(12)H_(12)^(2-) but also unveiled the nature of the B-H bond condensation and the general formation mechanisms of polyhedral boranes.This finding will facilitate the development of more effective synthetic methods for polyhedral boranes and spur their wide application.

关键词： Boranes polyhedral boranes dihydrogen bond nucleophilicity

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Recent advances of small-molecule fluorescent probes for detecting biological hydrogen sulfide

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Frontiers of Chemical Science and Engineering 2022年第1期16卷 34-63页

作者： Lei Zhou Yu Chen Baihao Shao Juan Cheng Xin Li Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals Zhejiang University of TechnologyHangzhou 310014China College of Pharmaceutical Sciences Zhejiang UniversityHangzhou 310058China

H_(2)S is well-known as a colorless,acidic gas,with a notoriously rotten-egg smell.It was recently revealed that H_(2)S is also an endogenous signaling molecule that has important biological functions,however,most of its physiology and pathology remains elusive.Therefore,the enthusiasm for H_(2)S research remains.Fluorescence imaging technology is an important tool for H_(2)S biology research.The development of fluorescence imaging technology has realized the study of H_(2)S in subcellular organelles,facilitated by the development of fluorescent probes.The probes reviewed in this paper were categorized according to their chemical mechanism of sensing and were divided into three groups:H_(2)S reducibility-based probes,H_(2)S nucleophilicity-based probes,and metal sulfide precipitation-based probes.The structure of the probes,their sensing mechanism,and imaging results have been discussed in detail.Moreover,we also introduced some probes for hydrogen polysulfides.

关键词： hydrogen sulfide fluorescent probe reducibility nucleophilicity copper sulfide precipitate hydrogen polysulfides

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Reactivity of Indoles through the Eyes of a Charge-Transfer Partitioning Analysis

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物理化学学报 2018年第6期34卷 692-698页

作者： OROZCO-VALENCIA Ulises GáZQUEZ José L. VELA Alberto Departamento de Quimica Centro de Investigacion y de Estudios Avanzados Av. Instituto Politecnico Nacional 2508 Colonia San Pedro Zacatenco Ciudad de Mexico 07360 Mexico. Departamento de Quimica Universidad Autonoma Metropolitana-Iztapalapa

A global and local charge transfer partitioning model,based on the cornerstone theory developed by Robert G.Parr and Robert G.Pearson,which introduces two charge transfer channels(one for accepting electrons(electrophilic) and another for donating(nucleophilic)),is applied to the reaction of a set of indoles with 4,6-dinitrobenzofuroxan.The global analysis indicates that the prevalent electron transfer mechanism in the reaction is a nucleophilic one on the indoles,i.e.,the indoles under consideration transfer electrons to 4,6-dinitrobenzofuroxan.Evaluating the reactivity descriptorswith exchange-correlation functionals including exact exchange(global hybrids) yields slightly better correlations than those obtained with generalized gradient-approximated functionals;however,the trends are preserved.Comparing the trend obtained with the number of electrons donated by the indoles,and predicted by the partitioning model,with that observed experimentally based on the measured rate constants,we propose that the number of electrons transferred through this channel can be used as a nucleophilicity scale to order the reactivity of indoles towards 4,6-dinitrobenzofuroxan.This approach to obtain reactivity scales has the advantage of depending on the intrinsic properties of the two reacting species;therefore,it opens the possibility that the same group of molecules may show different reactivity trends depending on the species with which they are reacting.The local model allows systematic incorporation of the reactive atoms based on the their decreasing condensed Fukui functions,and the correlations obtained by increasing the number of reactive atoms participating in the local analysis of the transferred nucleophilic charge improve,reaching an optimal correlation,which in the present case indicates keeping three atoms from the indoles and two from 4,6-dinitrobenzofuroxan.The atoms selected by this procedure provide valuable information about the local reactivity of the indoles.We further show that this information about the m

关键词： Chemical reactivity Conceptual DFT Charge transfer nucleophilicity Indoles Transition state prediction

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Ionic Liquid Solvent Based on Cyclic Guanidinium Cation for Nucleophilic Displacement Reactions

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Chemical Research in Chinese Universities 2004年第1期20卷 46-49页

作者： LINYing-jie QIUZhi-ming DUANHai-feng LISheng-hai ZHANGSuo-bo StateKeyLaboratoryofPolymerPhysicsandChemistry ChangchunInstituteofAppliedChemistryChineseAcademyofSciencesChangchun130022P.R.China CollegeofChemistry JilinUniversityChangchun130023P.R.China

The nucleophilic displacement reaction of n-bromooctane and potassium iodide in ionic liquid based on cyclic guanidinium cation(2) was investigated. The kinetic reasult shows that the rate of the reaction is enhanced in ionic liquid (2). The same reaction in [bmim][PF6](1)(where bmim=1-butyl-3-methylimidazolium) was also studied. It was found that as a reaction medium ionic liquid (2) is better than (1) for nucelophilic displacement reactions.

关键词： Ionic liquid Cyclic guanidinium nucleophilicity

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Quantifying Electrophilicity and Steric Effect with DFT

Quantifying Electrophilicity and Steric Effect with DFT

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中国化学会第26届学术年会理论化学方法和应用分会场

作者： Shubin Liu Renaissance Computing Institute, University of North Carolina, Chapel Hill, North Carolina 27599-3455, USA

＜正＞Theoretical justification for explicitly quantifying traditional chemical concepts such as electrophilicity, nucleophilicity, and steric effect within the conceptual framework of density functional theory will b... 详细信息

关键词： Keywords: electrophilicity nucleophilicity steric effect DFT.

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