共振光散射光谱法测定马来酸氯苯那敏

在pH 4.3的HAc-NaAc缓冲溶液中,荧光桃红与马来酸氯苯那敏依靠静电引力和疏水作用力形成离子缔合物,导致体系共振光散射增强.讨论了共振光散射增强的原因,并考察了一些因素对体系的影响.在最佳实验条件下,增强的共振光散射强度与马来酸氯苯那敏的浓度在0.2～12.0 μg/mL范围内呈良好线性关系,检出限为0.047...     

一种具有聚集荧光增强性质苯并咪唑化合物的合成及其对Zn2+的识别

利用5-甲基水杨醛和2-氨基苯并咪唑合成了一种结构简单的席夫碱荧光探针L,通过氢谱和碳谱表征了其结构。在乙醇-水混合溶液中对其进行了聚集荧光性能的测试,结果表明在混合体系下,随着水含量的升高探针L的荧光强度逐渐增强,表明探针L具有AIE性质。在乙醇体系中,L对锌离子具有高选择性识别,表现出明显的荧光增强,检测限可达到4.11×10~(-6 )M,表明了探针L对锌离子的检测有较高的灵敏度。     

光谱法研究核固红-Cu2+-阿莫西林体系及其分析应用

利用阿莫西林与Cu2+络合导致Cu2+对核固红的荧光猝灭程度减弱的特性,建立了荧光增强分析法检测阿莫西林含量的新方法。讨论了体系的紫外-可见吸收光谱、荧光光谱以及酸度、试剂浓度、反应温度、反应时间和离子强度等因素对体系荧光强度的影响。在最佳实验条件下,荧光强度的增强程度与阿莫西林质量浓度呈线性关系,线性范围为0.40~15.0μg/mL,检出限为0.29μg/mL。考察了一些金属离子和药物赋型物对体系的影响。将方法用于市售阿莫西林胶囊分析,回收率在100.4%~103.4%之间。     

萘酚-亚硝酸根对三聚氰胺的光谱响应及应用

用荧光光谱和紫外可见光谱研究了萘酚-亚硝酸根与三聚氰胺相互作用的性质,考察了溶液酸度对作用体系的影响.在4.1＜pH＜8.6时,三聚氰胺使体系荧光光谱增强,体系对三聚氰胺的线性响应范围为2.0～20 mg/L; 在8.6≤pH≤10.1时,三聚氰胺使体系荧光光谱降低,体系对三聚氰胺的线性响应范围为2.0～60 mg/L...     

基于乙醇和铝离子聚集诱导的铜纳米团簇（英文）

金属纳米团簇(MNCs)作为一种新型的纳米材料,具有合成方法简单、光稳定性强、毒性低、生物相容性好以及发光效率高等优点。在本研究中,使用"一锅法"合成谷胱甘肽保护的铜纳米团簇。在激发波长为370 nm时,GS@CuNCs的荧光发射波长在610 nm左右。铜纳米团簇可以通过有溶剂诱导和阳离子诱导两种方法聚集诱导增强其荧光强度。通过测定在不同溶剂(乙醇、甲醇、N,N-二甲基甲酰胺)中铜纳米团簇的荧光强度,探究了溶剂极性对聚集的影响。研究结果表明:在水溶液中铜纳米团簇只发射弱的荧光,随着乙醇含量从0%到85%,其荧光强度逐渐增强。此外,我们开发了一种新的选择性好、灵敏性高的检测铝离子的荧光探针。线性范围为2-20μmol·L-1,且检测限(LOD)为33 nmol·L-1。进一步探究可得,乙醇和铝离子能使GS@CuNCs荧光强度显著增加的机理为聚集诱导荧光增强。     

N-邻羧基苯基-N-(2-氨己基)草酰胺荧光特性的研究及应用

研究了酸度、温度对不对称草酰胺：N-邻羧基苯基-N-（2-氨己基)草酰胺(OBZE)荧光特性的影响。测定了该试剂的荧光量子产率。在pH8．0～9．5的H3BO3-NaOH缓冲介质中，NO3^-能使OBZE荧光强度定量猝灭，据此建立了荧光猝灭法测定NO3^-的新体系。OBZE的激发波长为210nm，发射波长为395nm。荧光猝灭值与NO3^-在0．004～0．68mg／L呈范围内线性关系，方法的检出限为0．004mg／L。实验了多种干扰离子的影响，已用于水中硝酸根离子的测定。     

基于乙醇和铝离子聚集诱导的铜纳米团簇

金属纳米团簇(MNCs)作为一种新型的纳米材料,具有合成方法简单、光稳定性强、毒性低、生物相容性好以及发光效率高等优点。在本研究中,使用“一锅法”合成谷胱甘肽保护的铜纳米团簇。在激发波长为370 nm时,GS@CuNCs的荧光发射波长在610 nm左右。铜纳米团簇可以通过有溶剂诱导和阳离子诱导两种方法聚集诱导增强其荧光强度。通过测定在不同溶剂(乙醇、甲醇、N, N-二甲基甲酰胺)中铜纳米团簇的荧光强度,探究了溶剂极性对聚集的影响。研究结果表明：在水溶液中铜纳米团簇只发射弱的荧光,随着乙醇含量从0%到85%,其荧光强度逐渐增强。此外,我们开发了一种新的选择性好、灵敏性高的检测铝离子的荧光探针。线性范围为2–20 μmol·L^-1,且检测限(LOD)为33 nmol·L^-1。进一步探究可得,乙醇和铝离子能使GS@CuNCs荧光强度显著增加的机理为聚集诱导荧光增强。     

基于水杨醛席夫碱结构的锌离子选择性荧光探针

设计并合成了一种新型锌离子荧光探针——4-N,N-二乙胺基水杨醛-2-吡啶肼席夫碱(1).在pH为7.0的50%水/乙醇(体积比)体系中,1对锌离子表现出显著的荧光增强响应.提高体系中的乙醇含量有利于获得更高的荧光放大倍数,在纯乙醇中,1对锌离子的荧光增强可达100倍.1对锌离子的荧光检测表现出良好的选择性,尤其可以区分锌离子的常见干扰离子镉离子.其线性范围为0.1~1.0μmol/L,检测限达到35 nmol/L.同时,1被成功用于实际水样中锌离子的定量检测.     

铈(Ⅳ)与抗坏血酸的荧光反应及其分析应用

实验发现,抗坏血酸在水溶液中能将无荧光的铈(Ⅳ)离子还原成能发射特征荧光的铈离子,加入三磷酸钠,可使体系的荧光强度大大增强,由此建立了间接灵敏测定抗坏血酸的方法.用1 cm石英比色池在激发和发射波长分别为303 nm和353 nm处测定其荧光强度;抗坏血酸在1.0×10-7～6.0×10-6 mol/L浓度范围内与体系的荧光强度呈线性关系;相关系数为0.9989; 检出限为1.0×10-8 mol/L(S/N=3).该法应用于样品测定,结果令人满意.     

掺Tb3+聚醋酸乙烯乳液的制备及性质研究

在PVAc乳液聚合过程,将一定比例的三氯化铽(TbCl3)溶液与醋酸乙烯(VAc)单体同步滴入聚合体系,获得掺Tb3+ 离子的PVAc乳液, 研究Tb3+离子对PVAc乳液性能的影响。研究表明,Tb3+ 离子对PVAc的颗粒形貌、大小及其质量指标影响不大,但对发光性能有一定的影响,即掺Tb3+ 离子的PVAc会产生很强的Tb3+ 离子特征荧光,且随Tb含量的提高,其荧光强度随之增强,无荧光浓度猝灭现象。     

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.