Synthesis and luminescence properties of novel 4-(N-carbazole methyl) benzoyl hydrazone Schiff bases

4-(N-carbazole methyl) benzoyl hydrazine was synthesized on the basis of carbazole, and then nine novel carbazolyl acylhydrazone Schiff bases were synthesized by the condensation reaction between 4-(N-carbazole methyl) benzoyl hydrazine and the substituted benzaldehydes. The relationships between the substituted group types and the UV fluorescence spectral properties, as well as the fluorescence quantum yields of the title Schiff bases were also investigated. The results show that the introduction of both the donating and accepting electron groups causes various grade redshifts of the fluorescence characteristic emission peak of the title Schiff bases to occur.The fluorescence quantum yields of the title Schiff bases with the donating group are increased, and the highest fluorescence quantum yield is up to 0.703.     

海藻酸动态共价交联水凝胶的制备及其自愈合性能

利用高碘酸钠氧化海藻酸得到带有醛基的海藻酸,利用水合肼与聚乙二醇反应得到末端为酰肼基的聚乙二醇,以二者为原料利用醛基与酰肼基反应形成酰腙键的动态化学反应,赋予天然生物大分子水凝胶优良的自愈性和p H响应性.通过红外光谱、核磁共振光谱、动态黏弹谱、电子万能试验机等表征了材料的结构、水凝胶的自愈合能力以及p H响应性.结果表明,该水凝胶具有良好的力学性能和自愈合能力,能够在不加热和不添加催化剂的情况下,在温和的生理环境下自发实现切口愈合.同时水凝胶具有p H响应性,在碱性环境中成凝胶,在酸性环境中则转变为溶液状态,并且这种凝胶—溶液转变可重复多次.这些优异的性能,加上简单的制备方法、良好的生物相容性将为这类材料在生物医用领域的应用提供坚实的基础.     

钳形酰腙类阴离子受体的合成及识别性质研究

设计合成了基于吲哚酰腙单元的钳形阴离子受体(1),UV-Vis滴定实验表明,它在含1%DMSO的CH3CN溶液中能选择性识别具有重要生物学意义的F-、Ac O-和H2PO4-(结合比均为1∶1且Ka104L/mol),但对Cl-、Br-、I-、NO3-、N3-、HSO4-和Cl O4-无识别作用。与它相比,端基为苯并呋喃的参照化合物2在同样溶剂中对上述3种阴离子的亲和性减弱,尤其是对H2PO4-。核磁滴定实验表明,受体1中的吲哚环NH和酰胺NH能产生协同效应,从而对阴离子产生了强效键合作用。     

A simple strategy for constructing acylhydrazone photochromic system with visible color/emission change and its application in photo-patterning

As a potential photochromic system, acylhydrazones exhibit many outstanding advantages including low cost, simple synthesis and high modifiability compared with some classic photochromic systems. However, the absorptionwavelengths of acylhydrazones usually locate in ultraviolet region, which makes the band separation between the absorbance maxima of its irradiated and unirradiated forms cannot be observed by naked eyes and greatly limits their practical applications. In this work, a simple strategy for constructing acylhydrazone photochromic system with visible color/emission change is provided. Rhodamine 6G hydrazine-2-aldehyde-pyridine Schiff base (compound 3) is designed and synthesized by combining acylhydrazone with Rhodamine 6G structure. The introduction of Rhodamine 6G moiety to 3 not only makes it remain all the advantages of acylhydrazone photochromic system but also exhibits visible photo-induced color/emission changes both in solution and in a solid matrix. Moreover, 3 exhibits reversible photochromic property with good fatigue resistance, which makes it an excellent candidate for photo-patterning.     

Unexpected simultaneous synthesis of trisubstituted quinolines and acylhydrazones under catalyst-free conditions

Trisubstituted quinolines and acylhydrazones were unexpectedly prepared from a reaction of N′-((2-aminophenyl)(phenyl)methylene)benzohydrazides with acetylenic esters. Using of N′-((2-aminophenyl)(phenyl)methylene)benzohydrazides led to obtain not only quinoline, but also a second pharmaceutical important product acylhydrazone. Notably, excellent yields, operational simplicity, short reaction times, and the avoidance of the use of catalysts make this approach an attractive complementary method to produce quinoline-2,3-dicarboxylates. The crystal structure of 5a was determined using single-crystal X-ray crystallography. The results showed that crystal packing diagram of 5a is of two pairs of molecules that have two independent alternate intermolecular 1D-polymeric H-bonds between two perpendicular molecules.     

Syntheses and room mesomorphic properties of novel gallic trimer and tetramer based on acylhydrazone structures

Two novel gallic trimer 7 and tetramer 8 based on acylhydrazone structures were designed and synthesized in yields 76% and 81%, respectively. Their structures were confirmed by ¹H NMR, ESI-MS, and elemental analysis. Their mesomorphic properties were investigated by DSC, POM, and XRD analyses. The mesomorphic results suggested that they possessed good room-temperature columnar liquid crystalline property with wide range of mesomorphic temperature. The ranges of mesomorphic temperatures for compounds 7 and 8 were as wide as 115°C and 124°C, respectively.     

Green synthesis of ethyl oxalate benzylidinyl hydrazides

Acylhydrazone compounds play an important role in medicine, materials and other fields. Herein we report the synthesis of ethyl oxalate benzylidinyl hydrazides by the reaction of benzaldehyde derivatives and ethyl oxalate hydrazide under catalyst-free conditions in H₂O near room temperature. This green synthesis method has the advantages of mild reaction conditions, fast reaction rate, non-catalytic, good yield and easy isolation. These synthesized ethyl oxalate benzylidinyl hydrazides can be used as Schiff base metal complexes of small molecule ligands.     

A simple strategy for constructing acylhydrazone photochromic system with visible color/emission change and its application in photo-patterning

As a potential photochromic system, acylhydrazones exhibit many outstanding advantages including low cost, simple synthesis and high modifiability compared with some classic photochromic systems. However, the absorption wavelengths of acylhydrazones usually locate in ultraviolet region, which makes the band separation between the absorbance maxima of its irradiated and unirradiated forms cannot be observed by naked eyes and greatly limits their practical applications. In this work, a simple strategy for constructing acylhydrazone photochromic system with visible color/emission change is provided. Rhodamine 6G hydrazine-2-aldehyde-pyridine Schiff base (compound 3) is designed and synthesized by combining acylhydrazone with Rhodamine 6G structure. The introduction of Rhodamine 6G moiety to 3 not only makes it remain all the advantages of acylhydrazone photochromic system but also exhibits visible photo-induced color/emission changes both in solution and in a solid matrix. Moreover, 3 exhibits reversible photochromic property with good fatigue resistance, which makes it an excellent candidate for photo-patterning.