Derivatives In Aqueous Solution Research Articles

Strong emission properties of 7-hydroxyindazolo[2,3-b]isoquinolin-12(7H)-one derivatives in aqueous solution

The emission of organic fluorophores is usually quenched in water solution. In this paper, strong emission of 7-hydroxyindazolo[2,3-b]isoquinolin-12(7H)-one derivatives were disclosed in aqueous solution. The absorption and fluorescence spectra of the ten derivatives were reported, they show absorption at 349–374 nm and emission at 409–483 nm. Among of them, the fluorescence quantum yield of 1c with alkyl groups is up to 85.9% in water; Compound 1g with benzyl group showed the maximum fluorescence intensity at 486 nm in water, which was attributed to S1→S0 transition and intramolecular hydrogen bond. While the fluorescence of 1j with m-methoxyphenyl group was quenched by photo-induced electron transfer process. The fluorescence intensities of selected compounds were stable in pH 3.0–9.0. Thus this work expands the study of new fluorophores which produce strong fluorescence in aqueous condition.

Effect of Hydrophobicity on the Self-Assembly Behavior of Urea Benzene Derivatives in Aqueous Solution

Urea benzene derivatives (UBD) with amphiphilic side chains showed self-assembly behavior in aqueous solution to form nanoparticles ~100 nm in size. Subsequent thermal treatment led to additional self-assembly of the nanoparticles due to dehydration of the amphiphilic side chains, producing microparticles. This self-assembly process was accompanied by a lower critical solution temperature (LCST) behavior, as revealed by the abrupt decrease in solution transmittance. In this study, three UBD (UBD-1–3) with different lengths of the alkyl segment in the amphiphilic side chain (namely, hexyl, heptyl, and octyl, respectively) were prepared to investigate the self-assembly behavior in aqueous solution. UBD-1–3 formed identical nanoparticles, with sizes in the 10~80 nm range but with different LCST values in the order 3 < 2 < 1. These results suggest a relationship between the hydrophobicity and the self-assembly behavior of UBD.

Molecular dynamics simulation of N-octyl-N-quaternized chitosan derivatives as a drug carrier

The dynamic amphiphilic behavior of N-octyl-N-quaternized chitosan derivatives in aqueous solution is investigated using molecular dynamics (MD) simulations. It is found that quaternization decreases the intra-chain hydrogen bond formation which leads to reduced rigidity of the chitosan backbone. The effect of octyl substitution is much less pronounced. Analysis of hydrogen bonding reveals the presence of a hydrogen bond within the quaternized glucosamine unit, which causes the distortion of the usual chair conformation. Also, H-bond formation with the solvent water molecules was found to stabilize the intra-chain HO3-O5 hydrogen bond. Additionally, an aqueous solution containing the 10%-N-octyl-50%-N-quaternized chitosan derivative (1O5QCS) and the anti-cancer drug 10-hydroxycamptothecin (10-HCPT) was also investigated using MD simulations. It was found that van der Waals and electrostatic forces have virtually equal contributions to the nonbonded interactions responsible for complexation. Furthermore, H-bond formation between drug and drug carrier contributes to lactone ring stability and subsequent bioavailability.

Benzo[e]indolium derivatives in aqueous solutions: Reaction with bisulfite and successive interaction with Cu2+ and Hg2+

A new benzo[e]indolium derivative 1 including pyridyl and thienyl groups was synthesized and characterized, which failed to response to Hg2+ or Cu2+ in aqueous system. However, it is interesting that when it reacted with bisulfite in HEPES buffer, the in situ generated ensemble as 1-SO3H displayed dramatic absorption and fluorescence changes after adding Cu2+ or Hg2+, which were contrary to the changes of 1 upon the addition of bisulfite ions. By contrast, the other two derivatives 2 and 3 showed the almost similar trends of spectral changes, which were short of ligating atoms N or S. The further investigation of 1HNMR spectra changes of 1 showed that C−SO3H bond may be interrupted because the good binding capacity of Hg2+ and Cu2+ with O of C−SO3H weaken the binding force of C−SO3H, which resulted in the recovery of ethylene with benzo[e]indolium block. The DFT calculations results further confirmed it.

Enantioselective Complexation of Chiral Oxirane Derivatives by an Enantiopure Cryptophane in Water

We show here that optically active cryptophane 1 bearing phenol functions can efficiently bind the two enantiomers of 2‐(chloromethyl)oxirane, ethyloxirane, and 2,2′‐bioxirane derivatives in aqueous solution. The binding process is characterized by high‐field 1H NMR signals that are specific to the encapsulated species. In all cases, an enantioselective effect was observed and a relationship between the molecular volume of the guest and the binding constant can be established, even though the flexibility of the guest molecule also seems to play a role. In this series, the 2,2′‐bioxirane guest is a particularly interesting example, because this compound possesses two stereogenic centers. Thus, in solution, three different pairs of enantiomers can be obtained in the presence of the optically active host 1. Electronic circular dichroism (ECD) spectroscopy has also been used to characterize these complexes; specific ECD spectra recorded in the 1Lb region were obtained for each diastereomer.

Discrimination and detection of benzaldehyde derivatives using sensor array based on fluorescent carbon nanodots

Excessive residual benzaldehyde derivatives in environment can cause severe ecological problems. There are currently less simple, rapid, sensitive and low-cost methods available to detect benzaldehyde derivatives. In this study, fluorescent nano-probes based on carbon nanodots (CDs) were developed for the determination of benzaldehyde derivatives in aqueous solution. Three kinds of classical CDs with different structure and photoluminescence characteristic were randomly chosen and prepared by using different carbon source and synthetic methods Static fluorescent quenching occurred to CDs in the presence of benzaldehyde derivatives. The concentration detection range covered from μM level to mM level, and the minimum detection limit reached 0.3 μM. Benzaldehyde derivatives with various structures and functional groups contributed differential fluorescent quenching degrees to CDs through the donor-acceptor electronic effect. On this basis, sensor array based on CDs was constructed for the discrimination and determination of benzaldehyde derivatives. Two principal components contributing 99.22% of the total variability were extracted by using principal component analysis method (PCA). PCA scattergraph was plotted and applied to descriminate five benzaldehyde derivatives intuitively, including 2,4-dihydroxybenzaldehyde, salicylaldehyde, m-hydroxybenzaldehyde, benzaldehyde and m-methylbenzaldehyde. Experimental results confirmed the practical utility and stability of the CD array for the assay of benzaldehyde derivatives.

Annihilation Delayed Fluorescence of Indole and Its Derivatives in Aqueous Solution

Spectral and kinetic characteristics of annihilation delayed fluorescence (ADF) of indole and its derivatives (5-methylindole, N-methylindole) were measured in aqueous solutions at room temperature. ADF spectra of indole and 5-methylindole consisted of two bands with wavelength maxima at 350 and 425 nm for indole and 350 and 390 nm for 5-methylindole. The short-wavelength band was due to ADF of monomers and coincided with the fast fluorescence spectrum. The long-wavelength band was attributed to ADF of excimers, the excited singlet states of which were populated by annihilation of triplet excimers. Triplet states of excimers were formed by collisions of molecules in triplet and ground states. The ADF spectrum of N-methylindole consisted of only the short-wavelength ADF band of monomers (λ = 352 nm). Lifetimes of monomer and excimer triplet states were estimated from the ADF kinetics.

Fluorescence, FTIR and 1H NMR studies of the inclusion complexes of the painkiller lornoxicam with β-, γ-cyclodextrins and their hydroxy propyl derivatives in aqueous solutions at different pHs and in the solid state

Lornoxicam forms inclusion complexes with all cyclodextrins but for their hydroxy-propyl derivatives, the drug also interacts with their outer surfaces.

Reaction mechanism of the cation radicals of thymine and thymine derivatives in aqueous solution: A theoretical study

Mechanisms of decomposition reaction of thymine cation radicals (T[Formula: see text]), 1-methyl substituted T[Formula: see text] (1-MeT[Formula: see text]), and 1,3-dimethyl substituted T[Formula: see text] (1,3-Me2T[Formula: see text]) generated by ionizing radiation or one-electron oxidation to thymine, 1-methylthymine and 1,3-dimethylthymine in aqueous solution have been investigated by theoretical calculations. Seven reaction paths including H2O or OH[Formula: see text] addition, and deprotonation were considered. The most likely reaction for T[Formula: see text] decomposition is N1 deprotonation forming T(-N1H)[Formula: see text]. When N1 hydrogen is replaced by methyl, T[Formula: see text] would deprotonate from C5 methyl group generating 1-methyl substituted UCH[Formula: see text] in neutral solution, and reaction with OH[Formula: see text] producing 1-methyl substituted T6OH[Formula: see text] in basic solution. When N1 and N3 hydrogens are both replaced by methyl, T[Formula: see text] decomposition reaction is similar to 1-MeT[Formula: see text], indicating that N3 hydrogen barely influences the subsequent reaction of 1-MeT[Formula: see text]. These results can provide theoretical support for experimental observations.

Design, synthesis and characterization of MOF-199 and ZIF-8: Applications in the adsorption of phenols derivatives in aqueous solution

In this work, the adsorption characteristics of metal-organic frameworks (MOFs: MOF-199 and ZIF-8) with two different types of structure were analyzed. MOF-199 consists of copper-based metal clusters while the ZIF-8 consists of organic molecules interlaced with zinc atoms and these have octahedral morphology and typical rhombic dodecahedron shape, respectively. The results of phenol (Ph) and p -nitro phenol (PNP) adsorption capacity from aqueous solution show that MOF-199 has a higher adsorption capacity: Ph 79.55% and PNP 89.3%, while for ZIF-8 the adsorption capacity was Ph 65.5% and PNP 77.0%. Adsorption of phenols was fit to Langmuir, Sips and Redlich-Peterson models and kinetics by pseudo-second order. Gibbs free energy (ΔG°) shows that adsorption processes studied are spontaneous.

Promising biocompatible hydrogels of crosslinked polyelectrolytes for biomedical applications

Abstract For the development of intelligent implant systems hydrogels (HG) from crosslinked ionic liquids feature a high potential to be utilised as a drug depot. Biocompatibility of the HGs is one key prerequisite for biomedical applications. HGs were polymerised from a variety of different ionic monomers based on methacrylate, methacrylamide, styrene or vinyl imidazolium derivatives in aqueous solution. N,N'-methylenebisacrylamide was used as crosslinker. CellQuanti-Blue™ Cell Viability Assay Kit was implemented to proof viability of L929 mouse fibroblasts. The predominant part of the HG eluates generated only a marginal reduction of less than 15% cell viability at 100% eluate concentration. This underlines the excellent suitability of these HGs for biomedical applications and revealed some promising candidates for the development of drug depots for implants.

Self-aggregation behavior of hydrophobic sodium alginate derivatives in aqueous solution and their application in the nanoencapsulation of acetamiprid

In this study, cholesteryl-grafted sodium alginate derivatives (CSAD) with different molecular weights were synthesized by esterification. The structure of CSAD was confirmed by FT-IR and 1H NMR spectrometers. The effects of pH and CSAD polymer concentration on the self-assembled behavior and particle size of CSAD were investigated by fluorescence measurement (FM) and dynamic light scattering (DLS). In the presence of Ca2+, the cholesteryl-grafted sodium alginate derivative was used for fabricating self-assembled nanoparticles that can effectively encapsulate the drug acetamiprid. The drug-loaded nanoparticles were characterized by transmission electron microscopy (TEM). The encapsulation efficiency (EE) and acetamiprid drug release behavior from the nanoparticles were also studied. The results reveal that CSAD self-assembled nanoparticles had a diameter of 100nm and were nonaggregated in aqueous media; Moreover, the encapsulation efficiency and the release behavior of nanoparticles were influenced by the MW of CSAD. The mechanism of acetamiprid release was found to vary from non-Fickian (anomalous) to Fickian transport with a decrease in the molecular weight of CSAD.

Lanthanide Complexes that Respond to Changes in Cyanide Concentration in Water.

Cyanide ions are shown to interact with lanthanide complexes of phenacylDO3A derivatives in aqueous solution, giving rise to changes in the luminescence and NMR spectra. These changes are the consequence of cyanohydrin formation, which is favored by the coordination of the phenacyl carbonyl group to the lanthanide center. These complexes display minimal affinity for fluoride and can detect cyanide at concentrations less than 1 μm. By contrast, lanthanide complexes with DOTAM derivatives display no affinity for cyanide in water, but respond to changes in fluoride concentration.

Lanthanide Complexes that Respond to Changes in Cyanide Concentration in Water

AbstractCyanide ions are shown to interact with lanthanide complexes of phenacylDO3A derivatives in aqueous solution, giving rise to changes in the luminescence and NMR spectra. These changes are the consequence of cyanohydrin formation, which is favored by the coordination of the phenacyl carbonyl group to the lanthanide center. These complexes display minimal affinity for fluoride and can detect cyanide at concentrations less than 1 μm. By contrast, lanthanide complexes with DOTAM derivatives display no affinity for cyanide in water, but respond to changes in fluoride concentration.

Relationship between Side-Chain Polarity and the Self-Assembly Characteristics of Perylene Diimide Derivatives in Aqueous Solution.

Perylene‐3,4,9,10‐tetracarboxylic acid diimides (PDIs) have recently gained considerable interest for water‐based biosensing applications. PDIs have been studied intensively in the bulk state, but their physical properties in aqueous solution in interplay with side‐chain polarity are, however, poorly understood. Therefore, three perylene diimide based derivatives were synthesized to study the relationship between side‐chain polarity and their self‐assembly characteristics in water. The polarity of the side chains was found to dictate the size and morphology of the formed aggregates. Side‐chain polarity rendered the self‐assembly and photophysical properties of the PDIs—both important for imminent water‐based applications—and these were revealed to be especially responsive to changes in solvent composition.

Thermodynamics of the dissociation of aminomethanesulfonic acid and its N-substituted derivatives in aqueous solutions at 293–313 K

ΔG, ΔH, and ΔS of the second dissociation step of aminomethanesulfonic acid and its N-methyl, N-hydroxyethyl, N-(tert-butyl), N-benzyl derivatives in aqueous solutions (at the isoelectric point where the ionic strength is 4.75 × 10–4 М) are determined on basis of pH measurements at 293–313 K. It is found that an increase of the electron-acceptor properties of the substituents at nitrogen atom reduces the effect temperature has on the thermodynamic functions of dissociation. Enthalpy–enthropy compensation at an isothermodynamic temperature of 303 K is recorded.

ML and ML2 complex formation between Ca(ii) and d-glucose derivatives in aqueous solutions.

The complex formation equilibria between Ca2+ ions and six carbohydrate derivatives related to d-glucose was quantitatively characterized by potentiometry, freezing point depression and polarimetry. Complexation could not be observed for d-glucose, while weak association was deduced for d-sorbitol and d-mannitol. Stronger complexes are formed with d-gluconate and d-heptagluconate due to the presence of the carboxylate group. In addition to the plausible 1 : 1 species, the 1 : 2 species can also be detected at higher ligand to metal ratios. The ML type complex is also formed with d-glucuronate and d-glucarate. The strong association for d-gluconate and d-heptagluconate was attested by freezing point depression measurements. Polarimetric results show that for these two ligands the specific rotation of the complexed and free anions is only slightly different. The stability of the 1 : 1 complexes follows the order: mannitol < sorbitol < glucuronate < heptagluconate ≈ gluconate < glucarate. The formation of the ML2 type species has been established for polyhydroxy ligands having at least one carboxylate group in addition to the conformational flexibility.

A Water-Soluble Fluorescent Probe for SO2 Derivatives in Aqueous Solution and Serum Based on Phenanthroimidazole Dye.

A water-soluble fluorescent SO2 derivatives probe PI-SO 2 based on a phenanthroimidazole dye, and a sensitive SO2 recognition site, aldehyde was constructed. The probe PI-SO 2 exhibits desirable properties such as high sensitivity, high selectivity and good water-solubility. Significantly, we have demonstrated that the probe PI-SO 2 is suitable for rapidly fluorescence detecting of SO2 derivatives in aqueous solution and serum. The application of the novel probe PI-SO 2 proved that it was not only a useful tool for the detection of SO2 derivatives in vitro, but also a potential assay for investigating the effects of SO2 derivatives, and demonstrating its value in practical applicationin of complex biological samples.

Water-Soluble Poly(p-aryleneethynylene)s: A Sensor Array Discriminates Aromatic Carboxylic Acids.

A chemical tongue consisting of 11 elements (four poly(p-aryleneethynylene)s (PAE) at pH 7 and pH 13, and seven electrostatic complexes formed from oppositely charged poly(p-aryleneethynylene)s at pH 7) discriminate 21 benzoic and phenylacetic acid derivatives in aqueous solution. The mechanism of discrimination is the fluorescence modulation of the PAEs, leading to quenching or fluorescence turn-on. The PAEs alone at both pH values and the tongue, consisting of the complexes only, discriminate the 21 acids with 92% (PAEs at pH 7), 95% (PAEs at pH 13), and 99% (complexes at pH 7) reliability after linear discriminant analysis (LDA). A sensor field with all 14 elements, according to LDA, discriminates all of the 21 acids with 100% accuracy.

Analysis of the Electronic Structure of Aqueous Urea and Its Derivatives: A Systematic Soft X-Ray-TD-DFT Approach.

Soft X-ray emission (XE), absorption (XA), and resonant inelastic scattering (RIXS) experiments have been conducted at the nitrogen K-edge of urea and its derivatives in aqueous solution and were compared with density functional theory and time-dependent density functional theory calculations. This comprehensive study provides detailed information on the occupied and unoccupied molecular orbitals of urea, thiourea, acetamide, dimethylurea, and biuret at valence levels. By identifying the electronic transitions that contribute to the experimental spectral features, the energy gap between the highest occupied and the lowest unoccupied molecular orbital of each molecule is determined. Moreover, a theoretical approach is introduced to simulate resonant inelastic X-ray scattering spectra by adding an extra electron to the lowest unoccupied molecular orbital, thereby mimicking the real initial state of the core-electron absorption before the subsequent relaxation process.