Spiropyran‐Conjugated Pluronic as a Dual Responsive Colorimetric Detector

Novel spiropyran‐conjugated Pluronic [polyethylene oxide (PEO)‐b‐polypropylene oxide (PPO)‐b‐polyethylene oxide (PEO)] micelles are developed as a new colorimetric detector showing photo‐ or thermo‐switchable behavior. Facile conjugation of spiropyran to Pluronic was confirmed by ¹H NMR, UV–Vis, and Fluorescence spectroscopy. A switchable photoluminescence is found depending on the irradiation with either UV or visible light, and temperature resulting from structural isomerization of spiropyran between spiropyran (SP) and merocyanine (MC) form. Cytotoxicity of the spiropyran‐conjugated Pluronic (SP‐PL) was evaluated following an MTT assay, whereas photo responsiveness of spiropyran within the micelles was determined by confocal laser scanning microscopy.     

Synthesis,structure, and photoluminescence properties of molecular complexes of bis(4-formyl-3-methyl-1-phenyl-1<Emphasis Type="Italic">H</Emphasis>-pyrazol-5-olato)cadmium(II) with aminoquinolines and 1-aminoisoquinoline

Molecular complexes of bis(4-formyl-3-methyl-1-phenyl-1H-pyrazol-5-olato)cadmium(II) with isoquinolin-1-amine, quinolin-3-amine, 4,6-dimethylquinolin-5-amine, and quinolin-6-amine have been synthesized, and their structure was studied by IR, UV, ¹H NMR, and X-ray absorption spectroscopy. Photoluminescence properties of the complexes have also been examined.     

Synthesis and functionalization of Poly[5,5′‐(silylene)‐2,2′‐dithienylene]s using silyl triflate intermediates†

Treatment of 5,5′‐dilithio‐2,2′‐dithiophene with (dimethylamino)methylsily bis(triflate)‐ or α, ω‐bis(triflate)‐substituted trisilanes gave poly[5,5′‐(silylene)‐2,2′‐dithienylene]s in high yields. The amino–silyl bond was cleaved selectively by triflic acid, leading to triflate‐substituted derivatives. Conversion of these compounds with nucleophiles gave other functionalized polymers. Platinum‐catalyzed hydrosilylation reactions between silicon–vinyl and silicon–hydrogen derivatives result in polymer networks which may serve as interesting preceramic materials. The structures of the polymers were proven by NMR spectroscopy (²⁹Si, ¹³C, ¹H). Results of thermal gravimetric analysis (TGA), UV spectrometry and conductivity measurements are given. Copyright © 1999 John Wiley & Sons, Ltd.     

Host–guest system of Vitamin B10 in β-cyclodextrin: characterization of the interaction in solution and in solid state

Conventional drugs are usually formulated for the immediate release of the medicinal substances and for obtaining the desired therapeutic effect. The aim of this paper was to investigate the possible interactions between Vitamin B10 and β-cyclodextrin (β-CD), to determine the physical-chemical characteristics and the interactions present in the corresponding inclusion compound. The so-obtained compounds were characterized by X-ray diffraction, DSC and FTIR spectroscopy. ¹H NMR and UV–vis spectroscopic methods were employed to study the inclusion process in aqueous solution. The X-ray powder diffraction patterns demonstrate the inclusion compound formation, especially for the lyophilized product where the amorphous phase dominates. The existence of the inclusion compounds obtained by different methods was confirmed by comparing with DSC and FTIR data of the pure compounds and the (1:1) Vitamin B10:β-CD physical mixture (pm). ¹H NMR measurements on aqueous solutions of Vitamin B10 and β-CD in D₂O allowed us to establish the corresponding Vitamin B10’s and cyclodextrin’s protons implied in the complexation process. 2D NMR spectroscopy established the geometry of the inclusion complex. ¹H NMR, UV–Vis and fluorescence data were used to obtain the stoichiometry and the stability constant of the complex.     

The true configuration of the benzilosazone isomers

The ¹H NMR-based argument previously used to assign configurations to the three stereoisomers of benzilosazone is briefly reviewed. The configuration of the stable isomer is shown to be Z,Z by single crystal X-ray diffraction analysis, instead of E,E as previously reported. This assignment, together with physical measurements and spectroscopic (NMR and UV) data, allows the establishment of the configuration of all isomers. Computational methods are employed to clarify the relation between the configuration of the isomers and their ¹H NMR, thus explaining the origin of the previous erroneous assignment.     

NMR study of the inversion at carbon 2 of some 1′3′3′-trimethylindolino disubstituted spirobenzopyranes

The ¹H NMR spectra of some 1′3′3′-trimethylindolino-6,8-disubstituted-spirobenzopyranes in equilibrium with more than 5% of their merocyanine isomer were taken at different temperatures in dimethylsulfoxide d₆. This presents evidence of a fast inversion process at the asymmetric spiro carbon-2. It is shown that the intermediate responsible for the inversion process is certainly not the merocyanine but more likely the open ring cis isomer of the spiropyran.     

New indoline spiropyrans containing azomethine fragment

The new spiropyran systems with an azomethine bridge were synthesized from a spiropyran containing aminogroup at 6′ position of the benzopyran fragment and substituted aromatic aldehydes. The chemical structure of compounds is confirmed by elemental analysis data, NMR (¹H and ¹³C) and IR spectroscopy. Photochemical studies revealed the presence of photochromic properties at room temperature for one of the obtained spiropyrans.     

Binuclear schiff-base complexes of copper(II) linked by phthaloyl as a bridging group

Binuclear Schiff-base complexes were prepared by bridging an unsymmetrical tetradentate Schiff-base complex of copper(II) with m- or p-phthaloyl. The complexes were characterized by means of elemental analyses, molecular weights, UV, IR and ¹H NMR (for metal-free ligands) spectra. ESR and magnetic susceptibility measurements show that the copper(II)copper(II) interaction is negligibly small.     

Chelate polymers. VI. New copolymers of the some siloxane containing bis(2,4-dihydroxybenzaldehyd-imine)Me with bis(p-carboxyphenyl)diphenylsilane

New high complex polymeric structures containing metal chelate sequences alternating, through esteric bridges, with silane units were obtained. The azomethine of 2,4-dihydroxybenzaldehyde with 1,3-bis(aminopropyl)tetramethyldisiloxane has been synthesized and in situ complexed with copper (II), nickel (II), cobalt (II) and cadmium (II). The obtained bis-phenolic chelates were covalently inserted in polymeric linear structures by their polycondensation with bis(p-carboxyphenyl)diphenylsilane as a diacid chloride. The structures of the obtained polymers were confirmed by IR, UV, ¹H NMR and elemental analysis. The characterization was made by TGA, DSC, solubility tests and GPC. The electrical conductivity of both chelate monomers and their polymers was investigated, all compounds showing typical semiconducting behaviors.     

New photochromic 1,1,3-trimethylspiro[benzo[<Emphasis Type="Italic">e</Emphasis>]indoline-2,3′-[3<Emphasis Type="Italic">H</Emphasis>]-pyrano[3,2-<Emphasis Type="Italic">f</Emphasis>]quinoline]

A new photochromic spiropyran of the benzoindoline series containing the quinoline moiety was synthesized. Its structure was determined by IR and ¹H NMR spectroscopy. The crystal structure of the new compound was established by X-ray diffraction. The photochromic properties of the synthesized spiropyran were investigated.     

Synthesis and Metal Complex Formation of a Bis(terpyridine) Derivative with a Phenylacetylene Framework

A new bis(terpyridine) derivative with a phenylacetylene framework was synthesized via a stepwise terpyridine construction strategy. The addition of ZnCl₂ to a solution of the bis(terpyridine) in chloroform resulted in UV/vis and ¹H NMR spectral changes because of complex formation.     

Self-assembly of bis(pyrrol-2-yl-methyleneamine)s bridged by flexible linear carbon chains

Two linear bis(pyrrol-2-yl-methyleneamine)s linked by a carbon chain, -(CH₂)_n-, n=2, 4, were synthesized in high yields by condensation of 2-formylpyrrole with the corresponding diamines. Self-assembly of the resulting bis(pyrrol-2-yl-methyleneamine) ligands with Zn(II) gave double-stranded helicates in excellent yields. Their structures were characterized by MS, ¹H NMR, ¹³C NMR, UV-Vis spectroscopic studies, and were confirmed by an X-ray crystal analysis. In CH₂Cl₂, both complexes 4 and 5 displayed moderate fluorescence.     

Bisthiourea: thermal and structural investigation

Bisthiourea derivatives 1,1′-(ethane-1,2-diyl)bis(3-phenylthiourea), 1,1′-(propane-1,3-diyl)bis(3-phenylthiourea), and 1,1′-(butane-1,4-diyl)bis(3-phenylthiourea) have been synthesized and characterized by IR, ¹H NMR, and ¹³C NMR. Suitable crystals of 1,1′-(propane-1,3-diyl)bis(3-phenylthiourea) were grown for single-crystal X-ray analysis and from the data it was observed that they organize into the P-1 space group. The thermal decomposition of these compounds has been studied by TG–DSC.     

New Photochromic Salt Spiropyran with Benzyl Substituent

A new salt spiropyran of indoline series containing benzyl substituent in the 8'-position of the [2H]-chromene moiety of the molecule has been synthesized and studied. The structure of the obtained compound has been confirmed by methods ¹H NMR and IR spectroscopy. The study of spectral characteristics and photochromic behavior of the target compound has shown that growing of its single crystal resulted in destruction on account of hydrolysis in acetonitrile. The ¹H NMR spectra of the initial salt spiropyran and product of hydrolysis have been compared.     

Synthesis,structural features and biochemical activity assessment of N,N′‐bis‐(2‐mercaptophenylimine)‐2,5‐thiophenedicarboxaldehyde Schiff base and its Co(II), Ni(II), Cu(II) and Zn(II) complexes

The tetradentate Schiff base ligand (SB), N,N′‐bis‐(2‐mercaptophenylimine)‐2,5‐thiophenedicarboxaldehyde was prepared via condensation of 2,5‐thiophene‐dicarboxaldehyde with 2‐aminothiophenol in a 1:2 molar ratio by conventional method. Additionally, its Co(II), Ni(II), Cu(II) and Zn(II) complexes have been synthesized and fully characterized by elemental analysis, FT‐IR, ¹H NMR, ¹³C NMR, UV–Vis, ESR, ESI‐mass, conductivity and magnetic susceptibility measurements. Spectral studies suggested that, the Schiff base coordinate metal ions through the azomethine N‐ and deprotonated thiol S‐ atoms. Based on UV–Vis absorption and magnetic susceptibility data, tetrahedral geometry was assigned for both Co(II) and Zn(II) complexes, whereas on the other hand, square planar geometry for both Ni(II) and Cu(II) complexes. The Schiff base and its metal complexes were screened for their in vitro antimicrobial activity by minimum inhibitory concentration (MIC) method. Free radical scavenging activity of the novel compounds was determined by elimination of 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radicals. In addition, the interactions of the free ligand and its complexes with calf thymus DNA (CT‐DNA) were explored using absorption, emission and viscosity measurements techniques.     

Synthesis and Antibacterial Activity of Novel 5,5′-(Pyridine-2,6-Diyl)bis(4-Arylideneamino-3-Mercapto-1,2,4-Triazole)-Related Derivatives

The reaction of 5,5′-(pyridine-2,6-diyl)bis(4-amino-3-mercapto-1,2,4-triazole) with various aromatic aldehydes in acetic acid yielded the corresponding 5,5′-(pyridine-2,6-diyl)bis(4-arylideneamino-3-mercapto-1,2,4-triazole) derivatives. The structures of the synthesized compounds as well as their intermediates were confirmed by elemental analysis, infrared spectra, ¹H NMR spectra and mass spectra studies. All the synthesized title compounds were screened for their antibacterial activities, and the preliminary results revealed that some of them showed good activities against Escherichia coli and Pseudomonas aeruginosa.     

Synthesis and Spectroscopic Characterization of Some Ferrocenyl Schiff Bases Containing Pyridine Moiety and Their Complexation with Cobalt,Nickel, Copper and Zinc

Three novel ferrocenyl Schiff base ligands containing pyridine moiety have been formed by 1:2 molar condensation of 1,1′‐diacetylferrocene with 2‐aminopyridine, 2‐amino‐5‐picoline or 2‐amino‐5‐chloropyridine, respectively. The ligands are 1,1′‐bis[1‐(pyridyl‐2‐imino)‐ethyl]ferrocene (L1); 1,1′‐bis[1‐(5‐methyl‐pyridyl‐2‐imino)ethyl]ferrocene (L2) and 1,1′‐bis[1‐(5‐chloropyridyl‐2‐imino)ethyl]ferrocene (L3). These ligands form 1:1 complexes with Co(II), Cu(II), Ni(II) and Zn(II) ions. The prepared ligands and their complexes have been characterized by IR, ¹H NMR, ¹³C NMR, UV/Vis spectra as well as elemental analysis. The spectral data of the ligands and their complexes are discussed in connection with the structural changes due to complexation.     

Bis benzothiophene Schiff bases: synthesis and in silico-guided biological activity studies

Since benzo [ b ] thiophene scaffold is one of the privileged structures in drug discovery as this core exhibitsactivities for different biological problems, in this study bis (benzo[ b ]thiophene-2-yl) alkyl methanimine derivatives (1-9) were synthesized by reacting benzo[ b ]thiophene-2-carbaldehyde with diamines. All newly compounds were characterized by IR, ¹H NMR and ¹³C NMR spectroscopic methods. Synthesized compounds were investigated using binary QSARbased models on therapeutic activity prediction of synthesized compounds and they showed high predicted activities in following diseases: bacterial, angina, allergy, depression and obesity. Thus, they were then tested for their antimicrobial and antileishmanial activities as a result of this theoretical study. Compound 1(N, N’- (propane-1,3-diyl) bis (1-(benzo [ b ] thiophene-2-yl)) methanimine) was found the most active compound in both diseases. Thus, its molecular docking studies were also carried out.     

瓜环与4,4'-二氨基二苯甲烷衍生物的相互作用

合成了三种长链多芳环多胺基客体, 它们分别由三种醛基吡啶异构体与4,4'-二氨基二苯甲烷形成的Schiff碱还原而成, 并得到¹H NMR以及质谱分析方法表征证实. 以核磁共振技术、紫外吸收光谱分析方法以及滴定¹H NMR方法为研究手段, 对瓜环(cucurbit[n]urils, n＝6～8)分别与三种4,4'-二[N-(吡啶甲基)氨基]二苯甲烷盐酸盐相互作用进行了考察. 实验结果表明, 六元瓜环与三种4,4'-二[N-(吡啶甲基)氨基]二苯甲烷盐酸盐相互作用均形成物质的量之比为2∶1的哑铃型包结配合物; 八元瓜环与三种N,N'-二(N-(吡啶甲基)二苯甲烷盐酸盐相互作用形成以类轮烷结构为主的包结配合物; 七元瓜环与三种N,N'-二(N-(吡啶甲基)二苯甲烷盐酸盐相互作用存在多种模式的竞争.