核化学与放射化学的研究进展

在我国核能快速发展的新形势下,新型核能资源的开发、乏燃料后处理、放射性废物处理与处置等核燃料循环化学研究日益活跃。随着科学技术的不断发展,离子加速器、反应堆、各种类型的探测器和分析设备、以及计算机技术等的发展,核化学与放射化学研究的范围和成果在不断扩展和增加,如核安全、环境放射化学、放射分析化学、放射性药物与标记化合物等,研究成果对于国防建设、核能发展、核技术应用等方面具有重要支撑作用。本文综述了近年来国内在上述领域所取得的研究进展。共引用参考文献161篇。     

二次纳流电喷雾电离耦合超高分辨质谱检测人体呼出气中相对高分子量化合物

二次电喷雾电离源耦合超高分辨质谱(SESI-UHRMS)有望检出人体呼出气中分子量大于300的相对高分子量化合物,这些化合物的发现将有助于更准确地理解呼出气中挥发性有机化合物(VOCs)的来源、产生机制以及SESI源电离机理,更好地实现SESI-UHRMS的转化应用.本研究自组装nanoSESI源(尚无商业产品)耦合四极杆-静电场轨道阱质谱(最高质量分辨率1.2×10~5),考察了该装置对健康人体呼出气中分子量为300~500化合物的检出情况.结果表明,所搭建的nanoSESI-UHRMS装置检测人体呼出气的重现性好、灵敏度高,可检出数十种分子量为300~500的化合物.根据这些化合物在单次呼气过程中信号强度随时间变化的趋势,推断其来源分别为内源性和外源性;各化合物的元素组成主要包括C,H,N和O,环-双键当量(RDB)的均值为(4.5±3.1),表明检出的化合物可能为醛酮或不饱和脂肪酸,容易在SESI源中被电离.本研究初步验证了自组建nanoSESI-UHRMS检测人体呼出气中相对高分子量化合物的可行性,为后续进一步开展方法应用奠定了基础.     

应用纳米零价铁富集银的研究

大量研究表明,纳米零价铁（nanoscale Zero-Valent Iron,nZVI）对水中重金属,尤其是金、银等稀贵金属,有良好的分离富集作用.利用纳米零价铁反应器证明了nZVI可从废水中分离低浓度的银离子（Ag⁺）,并生成高含量的“银矿石”.此外,也证明了反应区氧化还原电位能够反映nZVI与Ag⁺的反应速率和分离效率.利用X射线衍射仪、X射线光电子能谱和高分辨透射电子显微镜等手段对反应产物进行表征,证实了Ag⁺可被nZVI还原为单质银,并以纳米颗粒的形式（<10 nm）沉积在nZVI表面.与其他材料（常见吸附/还原材料）相比,nZVI具有效率高,受pH影响小的优点.研究结果表明,nZVI是一种能够高效富集痕量银资源并产生高价值纳米银的材料.     

银催化重氮酯与苯胺,亚胺的三组分反应（英文）

过渡金属催化重氮化合物的卡宾转移反应是有机合成反应的重要研究对象.在这一类反应中,包括环丙烷化、X-H(X=C,N,O,Si,S)插入以及羰基/亚胺叶立德环加成等反应得到了广泛的研究.2003年,胡文浩和Doyle课题组报道了一种新型的反应,即亚胺捕获看似不稳定的氨基叶立德中间体,合成具有高非对映选择性的1,2-二胺化合物.之后,他们又报道了一系列有关氨基叶立德和氧叶立德的研究,与不同的捕获剂,如酮,醛,β,γ-不饱和α羰基羧酸酯和偶氮二酸酸酯等发生反应,生成多种多样的产物类型,基本上都是采用Rh(Ⅲ)催化剂.迄今为止,没有采用其他类型的过渡金属催化剂的报道.最近,本课题组研究发现,银盐可以作为重氮化合物卡宾转移反应的催化剂,实现了重氮化合物与醛的[2+1]环加成反应合成环氧乙烷类化合物,及重氮化合物与醛、炔/烯三组分的[2+2+1]环加成反应合成二氢呋喃/四氢呋喃类化合物,在这些反应中,加入不同的配体可以调节Ag(Ⅰ)催化剂的催化活性,从而实现不同的反应过程.基于此,本文将探索Ag(Ⅰ)做催化剂催化重氮化合物与芳基胺及亚胺的三组分反应合成一系列1,2-二胺类化合物.研究发现,采用AgOTf/双噁唑啉配体配体作为催化剂组合,可以顺利地实现Ag(Ⅰ)催化重氮酯、芳基胺及亚胺的三组分反应.尝试了不同的配体,包括膦配体、卡宾配体以及双噁唑啉配体,最后发现,双噁唑啉配体配位的Ag(Ⅰ)催化反应的效果最好,极大地提高了Ag(Ⅰ)催化剂的催化活性,其具体的作用机理值得进一步研究.反应中,Ag(Ⅰ)催化剂的Lewis酸性对二胺产物的非对映选择性有较大的影响.其中,在对硝基苯基亚胺的反应中,产物的非对映选择性很高,大于铑催化反应的结果;而在其他类型亚胺的反应中,反应的非对映选择性较差.另一方面,由于Ag(Ⅰ)的Lewis酸性,反应过程中发生亚胺与芳基胺的氨基交换反应,从而导致氨基交换的二胺副产物的生成.本文对不同反应底物的各种效应进行了比较详细的研究.     

Zirconium–Porphyrin‐Based Metal–Organic Framework Hollow Nanotubes for Immobilization of Noble‐Metal Single Atoms

Single atoms immobilized on metal–organic frameworks (MOFs) with unique nanostructures have drawn tremendous attention in the application of catalysis but remain a great challenge. Various single noble‐metal atoms have now been successfully anchored on the well‐defined anchoring sites of the zirconium porphyrin MOF hollow nanotubes, which are probed by aberration‐corrected scanning transmission electron microscopy and synchrotron‐radiation‐based X‐ray absorption fine‐structure spectroscopy. Owing to the hollow structure and excellent photoelectrochemical performance, the HNTM‐Ir/Pt exhibits outstanding catalytic activity in the visible‐light photocatalytic H₂ evolution via water splitting. The single atom immobilized on MOFs with hollow structures are expected to pave the way to expand the potential applications of MOFs.     

手性磷酸催化的C（3）-取代吲哚和甲基乙烯基酮不对称串联反应

3位含有季碳手性中心的吲哚啉并环化合物是一类非常重要的化合物, 广泛存在于各种天然产物和具有生物活性的分子中. 化学家们发展了多种有效的途径来合成这类化合物. 其中以方便易得的吲哚衍生物为起始原料, 利用不对称去芳构化\环化串联的方法最为简单高效, 但多数工作都是从色胺或色醇衍生物出发, 合成二氢吡咯并吲哚啉或二氢呋喃并吲哚啉化合物. 因此, 发展其他类型的吲哚衍生物的不对称去芳构化\环化反应显得非常有必要. 作者课题组发展了手性磷酸催化的吲哚衍生物与甲基乙烯基酮的不对称Michael加成\环化串联反应. 以5 mol% (R)-SPINOL为骨架的手性磷酸(R)-4c为催化剂, 以中等到良好的收率和优秀的对映选择性构建了一系列手性吲哚[2,3-b]并氢化喹啉化合物, 而且该催化体系对于克级规模反应同样能够获得很好的结果.     

Synthesis,Characterizations, Magnetism and Thermal Degradation of a 2‐Fold Interpenetrated 3D Cobalt‐Organic Framework

A new coordination polymer, [Co₂(L)₂(4,4′‐bipy)]_n·3nH₂O ( 1 ) based on 5‐(3‐methyl‐5‐phenyl‐4H‐1,2,4‐triazol‐4‐yl)isophthalic acid (H₂ L ) and 4,4′‐bipyridine (4,4′‐bipy) has been hydrothermally synthesized and characterized by single‐crystal X‐ray diffraction, XRPD, IR, and elemental analysis. Temperature‐dependent magnetic susceptibility and thermal degradation for 1 were also studied. The asymmetric unit of compound 1 consists of two crystallographically independent Co(II) ion, two L ^2? ligand, one 4,4′‐bipy ligand, and three lattice water molecules. The 2D triangle networks were linked by the bridging 4,4′‐bipy ligand to give rise to a 2‐fold interpenetrated 3D architecture. The simplest cyclic motif of the 2D networks is a triangle ring consisting of three Co(II) cations and three L ^2? ligands. So we can define Co(II) ions as 4‐connected nodes and the L ^2? ligands as 3‐connected nodes. Thus, the 3D structure can be described as a 2‐fold parallel interpenetrated ins InS 3,4‐conn topology.     

Molecularly engineered graphene surfaces for sensing applications: A review

Graphene is scientifically and commercially important because of its unique molecular structure which is monoatomic in thickness, rigorously two-dimensional and highly conjugated. Consequently, graphene exhibits exceptional electrical, optical, thermal and mechanical properties. Herein, we critically discuss the surface modification of graphene, the specific advantages that graphene-based materials can provide over other materials in sensor research and their related chemical and electrochemical properties. Furthermore, we describe the latest developments in the use of these materials for sensing technology, including chemical sensors and biosensors and their applications in security, environmental safety and diseases detection and diagnosis.     

Fluorescent Coumarin–Artemisinin Conjugates as Mitochondria‐Targeting Theranostic Probes for Enhanced Anticancer Activities

Mitochondria‐targeting theranostic probes that enable the simultaneously reporting of and triggering of mitochondrial dysfunctions in cancer cells are highly attractive for cancer diagnosis and therapy. Three fluorescent mitochondria‐targeting theranostic probes have been developed by linking a mitochondrial dye, coumarin‐3‐carboximide, with a widely used traditional Chinese medicine, artemisinin, to kill cancer cells. Fluorescence images showed that the designed coumarin–artemisinin conjugates localized mainly in mitochondria, leading to enhanced anticancer activities over artemisinin. High cytotoxicity against cancer cells correlated with the strong ability to accumulate in mitochondria, which could efficiently increase the intracellular reactive oxygen species level and induce cell apoptosis. This study highlights the potential of using mitochondria‐targeting fluorophores to selectively trigger and directly visualize subcellular drug delivery in living cells.     

2-乙酰吡嗪缩肼基甲酸甲酯的镍和镉配合物的晶体结构及荧光性质

合成并通过X射线单晶衍射、元素分析及红外光谱表征了配合物[Ni(L)₂] (1)和[Cd(HL)(CH₃OH)(NO₃)₂] (2)的结构(HL为2-乙酰吡嗪缩肼基甲酸甲酯)。单晶衍射结果表明,配合物1中,Ni(Ⅱ)离子与来自2个阴离子配体L-的N₂O电子供体配位,形成扭曲的八面体配位构型。在配合物2中,Cd(Ⅱ)离子拥有双帽三棱柱配位构型,与1个中性配体HL,2个双齿配位硝酸根和1分子甲醇配位。此外还研究了配合物1和2的荧光及热性质。