大型仪器分析实验教学多层次培训体系的建立与实践

在大型仪器分析实验教学中,为了提升学生对基础知识的运用能力,提高学生的动手能力、创新能力,通过引入培训、教学双模式,建立了大型仪器多层次（即基础理论培训、上机操作技术培训和仪器功能应用培训）培训体系。实践证明这种多层次培训体系搭建了学生与专家、学者之间交流的平台。从理论讲解到操作,再到应用的多层次培训体系有效地弥补了大型仪器实验教学中单一教学模式存在的不足,可以很好地培养本科生和研究生的学习兴趣,提高学生分析问题、解决问题的科研能力,同时提升了仪器使用效率,储备了大量仪器方面的专业人才。     

仪器分析实验教学改革实践

在仪器分析实验教学中运用启发式教学,注意理论联系实际,利用网络教学平台和虚拟实验教学强化实验预习,强调数据处理,利用废旧仪器,完善实验考核方案,旨在培养学生的实践和创新能力。     

基于Unity 3D的气相色谱仪虚拟仿真实验系统的构建

虚拟仿真技术被广泛认为是一项重大技术进步,可以提供一种新颖的教学方式,能促进化学学习,打破传统教育方法的限制。三维交互式的气相色谱仪虚拟仿真实验系统使用当前主流的Unity 3D软件作为系统的主要开发工具。构建的系统主要包含仪器的动态原理展示、三维结构展示及仿真实验3部分。系统中的模型全部采用三维设计,场景逼真,能够全方位地向使用者展现真实仪器的外形及内部结构,令使用者如同置身于真实实验室中,获得身临其境的操作体验,从而更容易学习和掌握仪器组成、工作原理及相关的实验技能。系统不仅满足了仪器培训和化学实验教学的基本需求,而且对虚拟仿真技术在化学中的应用起了示范效应和推广作用。     

线上线下混合式"仪器分析实验" 课程实践与思考——以气相色谱实验为例

在新型冠状病毒肺炎疫情期间,由于学生无法返校,中国科学技术大学化学实验教学中心仪器分析实验课程组利用自主开发的大型仪器虚拟仿真软件,应用"智慧课堂"教学模式,进行了线上教学与实验;在学生返校后,又开展了真实实验。本文介绍了该次实验课程开展过程中的线上线下教学活动及教学效果总结,提出了对于线上线下混合式一流课程建设的一些思考。     

高校公共仪器平台信息化综合管理系统的开发与实现

北京大学分析测试中心信息化综合管理系统(网址:http://aic.pku.edu.cn/)是一个用于仪器预约与管理的系统,系统集网站管理、送样预约、上机预约、培训管理、财务管理、耗材领取、统计等子系统于一体,系统功能全面强大,运行稳定,操作便捷,界面友好。大大改善了分析测试中心的信息化建设,并极大提高了工作效率和管理水平。     

虚拟仿真技术在大学分析化学实验教学中的应用*

针对传统分析化学实验教学中的不足,介绍了大学分析化学实验虚拟仿真线上教学项目的建设内容及其应用实效,并对虚拟仿真实验技术下一步的发展方向进行了设想。通过近2个学年的教学实践,发现以虚拟仿真实验辅助现场教学,可有效弥补传统分析化学实验教学中学生预习效果差、试剂废液产生量大、安全隐患频发等方面的缺陷;同时,虚拟仿真实验系统的考核评价、分析统计功能为教师在开展现场实验教学过程中,针对学生知识点掌握的薄弱环节开展针对性强化指导训练提供了有效手段。本虚拟仿真实验系统为虚拟仿真技术在大学分析化学实验教学领域的推广应用提供了有益借鉴。     

高分子专业“互联网+实验教学”模式的探索与实践

在"互联网+教育"发展的新阶段,依托一流专业建设项目,对本专业的"互联网+实验教学"模式进行了探索和实践。将虚拟仿真实验、大型仪器虚拟操作软件、微视频等现代化信息技术手段引入到实验课程教学中,以此推进现代信息化技术手段与实验教学的深度融合,实现专业实验教学的"互联网+实验教学"模式改革。这种基于网络技术的线上和线下互动式教学,增强了学生学习和思考的兴趣,提高了实验教学信息的广度和深度,促进了实验教学水平的提高。     

聚醋酸乙烯酯的光引发可控合成——介绍一个高分子化学综合实验

本实验开展了醋酸乙烯酯的可逆加成-断裂链转移自由基聚合(RAFT),分别运用偶氮二异丁腈(AIBN)引发和可见光引发两种方式进行了聚合反应,运用核磁共振和凝胶色谱等多种手段对所得聚合物结构进行了表征与分析。通过比较AIBN引发与光引发所获得聚合物端基结构的异同,加深了学生对RAFT聚合方法原理的理解。同时,运用该方法实现了聚合物两端端基结构的高度功能化,深入体会聚合物合成设计概念。本综合实验教学不仅通过对比法加深了学生对实验原理和专业知识的理解,提升了学生创新研究能力,而且训练了学生的实验操作技能、大型仪器使用能力和结果分析能力,提升了综合素质。     

基于内扩散有效因子测定实验的3D虚拟仿真实验预习系统设计

催化剂内扩散有效因子测定实验是大学基础实验之一,传统的实验预习方法注重理论介绍,不能给学生以直观的感受和操作体验,导致学生对实验设备、操作步骤比较陌生。针对此问题,设计出一种基于3D虚拟仿真技术的实验预习系统,用操作3D虚拟仿真实验模型的方式来提高学生的实验预习效果。此系统还能基于一种惩罚扣分评分模型进行考核,能够对操作数据进行统计分析,不仅帮助学生加深对实验的理解,而且有利于提高教学质量。     

加强实验操作考核客观评定《分析化学》课程成绩

在搞好课堂理论教学的同时，要加强实验课程的教学和考核。提出了实验操作考核的具体内容及方法。强调正确掌握定量分析仪器操作的重要性。将学生理论考试成绩与实验操作考核成绩有机结合起来，客观评定该课程成绩     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.     

Synthesis of N-substituted carbazolones from α-iodo enaminones via Pd(0)-catalyzed intramolecular coupling under microwave irradiation

A variety of N-aryl and N-alkyl carbazolones were conveniently achieved in good to high yields via Pd₂(dba)₃-mediated intramolecular coupling of N-substituted α-iodo enaminones under microwave irradiation. The Pd(0)-catalyzed cyclization was found to proceed favorably with the more electron-deficient phenyl ring during the reactions involving unsymmetrical N,N-diaryl α-iodo enaminones. This unique property enables the construction of carbazolone skeleton containing nitro substituted benzenoid ring.     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

Synthesis of substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles by intramolecular nitrilimine cycloaddition

Both substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles have been synthesized by the 3+2 intramolecular dipolar cycloaddition of nitrilimines to alkynes. This cyclization has been extended to more versatile 3-bromo derivatives by the use of alkynylbromides as dipolarophiles.