吲哚啉螺吡喃化合物光致变色性能的研究及在生物细胞成像中的应用

吲哚啉螺吡喃是一种重要的光致变色化合物,由于具有良好的变色回复性、抗疲劳性而得到广泛的关注.本文合成了1′-羟乙基-3′,3′-二甲基吲哚啉-6-硝基螺吡喃,研究了该化合物在紫外-可见光交替照射下紫外吸收强度的变化,并测试了光照前后化合物的荧光光谱.在开环态时,化合物具有优良的荧光性能,可以成功应用于细胞成像,在活细胞中可获得清晰的荧光成像图,同时也可以发挥螺吡喃光致变色可循环、耐疲劳等优势.     

冠醚螺吡喃化合物的合成和光致变色性质

合成了四个新的6位带不同取代基的含冠醚结构单元吲哚啉螺苯并吡喃化合物(5a-5d),研究了其光致变色性质和离子诱导光致变色作用及取代基的影响。结果表明冠醚能稳定螺吡喃开环形式,碱金属离子对冠醚螺吡喃的生色有诱导作用;6位为吸电子基团时,螺吡喃开环形式的稳定性增加,而6位为推电子基团时,螺吡喃开环形式的稳定性降低。另外,就稳定螺吡喃开环体的作用来说,吲哚啉环上的取代基效应和苯并吡喃环上的正好相反。     

新型1,8-萘酰亚胺类光控双色荧光分子开关的合成及性质

设计合成了三种新型键合螺吡喃单元的1,8-萘酰亚胺类化合物.光致变色性质研究结果表明:三种化合物与经典螺吡喃相比,其开环过程光响应时间较长或难以检测到其开环的部花菁结构,分析了其光响应时间变长的原因.SP3分子中由于存在强吸电子基,其在固体介质以及有机溶剂中光致变色现象较为明显,在不同的有机溶剂中显示出了负的溶剂效应,螺吡喃单元开环体的吸收波长没有明显的改变.荧光性能检测发现:化合物SP1、SP2在硅胶中光照前后有较为明显的荧光颜色改变,在聚甲基丙烯酸甲酯(PMMA)中和有机溶剂中检测不到其光照前后荧光的变化.未检测到化合物SP3光照前后在丙酮中的荧光改变,但是在聚乙二醇(200)中光照前发射绿色荧光,光照后变为橙黄色荧光,荧光光谱也检测到了其变化过程.SP3在薄层硅胶中光照前后发生的荧光颜色改变更为明显,随着照射时间的延长其荧光由绿色变为黄绿色,橙黄色最后变为红色,化合物在PMMA膜中的荧光光谱也表明了化合物SP3具有光控双色荧光分子开关性能.     

螺吡喃化合物在分析化学中的应用

螺吡喃作为一种有机光致变色化合物,能够发生无色闭环体螺吡喃与有色开环体部花菁之间可逆的结构异构化,由于具有特殊的分子识别能力和信号传导功能,已经成为分子探针领域极具吸引力的主体分子之一。螺吡喃不仅被广泛应用于光电材料领域作为分子器件,而且作为传感器广泛应用于分析化学领域。研究者们设计了多种具有不同结构的螺吡喃分子,将其应用于光化学和电化学传感领域。本文系统综述了螺吡喃化合物在分析化学领域的研究进展,包括螺吡喃作为光学探针在分子识别(对金属离子、阴离子及有机分子的定性及定量分析)方面的应用,以及螺吡喃在电化学免疫传感器中的应用。     

两种新型阳离子吲哚啉螺吡喃的合成、表征和光致变色性质的研究

螺吡喃是一类重要的光致变色化合物．螺吡喃的正向光致变色是指在紫外光照下,螺吡喃分子的Ｃ—Ｏ键异裂,由闭环无色体（ＳＰ）可逆地变成开环有色体（ＭＣ）．所形成的有色体可以在暗条件下热致褪色或在可见光照下褪成无色体（示意图１）．它的逆向光致变色是指某一类螺...     

吲哚啉螺萘并吡喃的合成和时间分辩光谱研究

螺萘并吡喃类化合物是一类重要的有机光致变色化合物,因可用作光敏、光信息和光记录材料,而引起人们的研究兴趣．其中对螺苯并吡喃和螺嗪两类化合物的开环机理有较多的文献报道［１,２］,而对螺萘并吡喃的研究则少得多．我们合成了３个螺萘并吡喃化合物（其中ＳＰ１...     

含BOC保护基团的螺吡喃类化合物的合成及其光致变色性能的研究

合成了5-[N-(叔丁氧甲酰基)氨基]-1,3,3-三甲基-6′-硝基吲哚啉螺吡喃(BOCSPI)和5-[N-(叔丁氧甲酰基)氨基]-1,3,3-三甲基-6′-硝基-8′-甲氧基吲哚啉螺吡喃(BOCSPII)两种光致变色化合物,采用紫外-可见光谱法研究了其在溶液和以不同质量比掺杂在聚甲基丙烯酸甲酯(PMMA)膜中的光致变色性能.研究表明螺吡喃的高掺杂量不利于其开环和闭环态的转化,BOCSPII分子中的甲氧基有利于有色开环体的部花菁的稳定.     

动态吸收光谱研究6-硝基-1’,3’,3’-三甲基吲哚啉螺苯并吡喃的光致变色性质

利用自行搭建的线阵CCD连续直读紫外-可见吸收光谱仪,研究了合成的螺吡喃类化合物6-硝基-1’,3’,3’-三甲基吲哚啉螺苯并吡喃的光致变色反应。通过研究在光照后闭环体开环与光照后开环体的闭环两个过程的光谱变化,讨论了合成产物的光致变色性质。证明该化合物的开环反应是一个快反应,在光照下的变色过程则是一个振荡平衡过程,而开环体的退色反应是一级动力学过程。     

一种含螺吡喃和肉桂酸酯双光功能基团的光致变色染料的合成与性能

合成了一种含有光致聚合肉桂酸酯基团的新型光致变色螺吡喃染料,研究其与普通螺吡喃染料在不同高分子材料中的光致变色和热退色过程(PMMA和PVCi).通过UV-Vis光谱、NMR谱和IR光谱研究了新型染料中的肉桂酸酯基团的光致聚合过程,考察了其对螺吡喃结构的光致变色显色体热稳定性的影响.     

一种卟啉-螺吡喃化合物的合成及其离子响应行为研究

合成了一种卟啉-螺吡喃化合物,并对其结构进行详细表征。在此基础上,通过紫外光谱研究了其光致异构与离子响应特征,并提出了一种解释卟啉环与螺吡喃之间耦合行为的新机制。研究结果表明,金属离子会诱导合成的卟啉-螺吡喃分子产生新的构象,从而影响螺吡喃的光致异构。此外,随着离子半径以及亲电能力的不同,卟啉-螺吡喃衍生物的光学特性也产生明显差异。这种卟啉-螺吡喃化合物为构建新型离子探针提供了一种思路。     

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%).     

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.     

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.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

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.