Naphthol Molecules Research Articles

Effects of Substituent and Temperature on the Electronic Properties and Thermodynamics Parameters of 1-(Benzothiazolylamino) Methyl-2-Naphthol: A Computational Study

The effects of substituent and temperature on the 1- (benzothiazolylamino) methyl - 2- naphthol molecules were studied at CAM-B3LYP/6-311G (d,p) level of theory. Selected substitutions were NH2, OH, Me, F, Cl, CHO, COOH, CN and NO2. Substituent effect on the frontier orbitals energies, HOMO-LUMO gap, chemical potential, and electrophilicity were explored. Dependencies of energy changes, reactivity properties and thermodynamics parameters (G, H and S) on the Hammett's constants (p) were provided. Thermodynamics parameters values of the formation reaction were studied reaction at 100-1000 K range. Computational investigation of the substituents and temperature influences on the formation reaction of the 1-(benzothiazolylamino) methyl-2-naphthol showed the negative E values in the studied reactions. Calculated dipole moment values reveal the presence of the EWGs induced a larger dipole moment compared with the EDGs. Higher negative values were found in the presence of EWGs compared to EDGs. Frontier orbitals were stabilized in the presence of EWGs. However, frontier orbitals were destabilized in the presence of EDGs. Thermodynamic analysis revealed that these reactions were non-spontaneous and exothermic. The G and negative H values were increased with increasing the temperature. Optimization and vibrational analysis were done with Gaussian 09 software package. The standard 6-311G(d,p) basis set was considered for the elements, respectively. CAM-B3LYP functional was used for the optimization of the geometries of the compound . This functional is Handy and coworkers’ long range corrected version of B3LYP using the Coulomb-attenuating method The identities of the optimized structures as an energy minimum were confirmed by vibrational analysis

Electrochemical sensing platform for naphthol isomers based on in situ growth of ZIF-8 on reduced graphene oxide by a reaction-diffusion technique

Enhancing the dispersibility and conductivity is an effective solution to develop the application zeolitic imidazole frameworks (ZIF) in the electrochemical field. This work thus employs a novel reaction–diffusion framework (RDF) technique for the in situ growth of ZIF-8 crystals on graphene oxide (GO@ZIF-8) matrixes. In detail, the outer electrolyte of 2-methyl imidazole naturally diffuses into the inner agar gel matrix containing Zn2+ cations and GO nanosheets. The long reaction–diffusion makes the growth of ZIF-8 crystals controllable in a vertical gradient. After thermal treatment, the title product of ZIF-8 in situ grown on reduced graphene oxide (rGO@ZIF-8) is obtained and thus exhibits good dispersibility, high conductivity, large surface area, and more catalytic sites. The glassy carbon electrode (GCE) was modified by casting the rGO@ZIF-8 suspension. The obtained rGO@ZIF-8/GCE displays excellent catalytic activity toward naphthol (NAP) isomers. Under the optimal conditions, the amperometric currents of 1-NAP and 2-NAP demonstrate the good linear relationship in wide ranges of 0.05–12 μM and 0.02–15 μM, respectively. Their limits of detection are as low as 15 and 17 nM, respectively. The fabricated modified electrode exhibits excellent selectivity, stability, and reproducibility. The sensor is also utilized to detect NAP molecules in real water samples and indicates good accuracy and reliability.

Functionalized gold nanoparticles for 2-naphthol binding and their fluorescence properties

Abstract Thiol-modified β-cyclodextrin functionalized gold nanoparticles (AuβCD NPs) were synthesized for binding 2-naphthol in aqueous solution. On the bases of the infrared spectroscopic results, the thiolated cyclodextrin molecules (βCD-(SH) 2 ) are chemically bound to the gold nanoparticle surface. As a consequence of functionalization, a 3-dimensional hexagonal self-assembled structure developed in the dispersion, due to the interaction between the incorporated naphthol molecules. The red-shift of plasmon resonance maximum by 17 nm in the UV–vis spectrum by the addition of 90 μM 2-naphthol solution to the gold dispersion confirmed the adsorption of 2-naphthol in the βCD rings modified AuNPs. The in situ synthesis of AuNPs in the βCD solution resulted in fluorescent AuβCD system and the adsorption of 2-naphthol significantly modified the fluorescence properties. Upon excitation at λ ex = 225 nm, the emission peaks of 2-naphthol appearing at 360, 412 and 720 nm are replaced by a peak at 400 nm and by a second peak at 590–610 nm depending on the AuβCD NP concentration. The quenching effect of AuNPs and βCD-(SH) 2 molecules on the emission of 2-naphthol was evaluated based on the Stern–Volmer equation. The determined reaction free-enthalpy (Δ G = −25.44 kJ/mol) data was similar to that of obtained from the microcalometric titration of 2-naphthol-βCD-(SH) 2 . The interaction of bulk or particular Au with naphthol was also examined in 2D system using surface plasmon resonance (SPR) method.

Preparation, Characterization and Thermal Behavior of Copper(II) Complex with 1-(6-Hydroxynaphthalen-2-Yl)butane-1,3-Dione

A complex of Cu(II) with 1-(6-hydroxynaphthalen-2-yl) butane-1,3-dione (HNBD) was synthesized and characterized by elemental analysis, IR, UV and TG-DTA techniques. IR spectra as well as UV-visible absorption measurements indicated that Cu(II) ion was coordinated to the HNBD ligand. The TG-DTA curves showed that the thermal decomposition for Cu(II) complex was a three-steps process. At first, the complex had a mass loss of water molecules at temperature below 134°C, then the thermal decomposition of the anhydrous complex was a two-stage process, which corresponded to the loss of two naphthol molecules and the oxidative decomposition of other organic fragments of ligand. The final decomposition product of the complex was CuO.

Fluorescence quenching of naphthols by Cu2+ in micelles

Effect of the micelles of anionic, cationic and non-ionic surfactants on the fluorescence quenching of 1- and 2-naphthols has been studied in the presence of copper ion. The excited state lifetime, dynamic and static quenching constants for these systems have been determined. Fluorescence quenching in water and SDS micelle is due to the collision of the fluorophore with the quencher with a small static component. The negatively charged naphtholate ions in the excited state are quenched with significantly higher rates than the neutral naphthol molecules, which are located further inside the mesophase. CTAB micelle is less effective than the SDS micelle for fluorescence quenching. The effect of CTAB on water-assisted excited-state deprotonation has been investigated in the presence of ZnSO4. For TX-100 micelle there is negligible quenching even at higher concentration of the quencher.

Peroxidase‐Mediated Polymerization of 1‐Naphthol: Impact of Solution pH and Ionic Strength

Peroxidase-mediated oxidation has been proposed as a treatment method for naphthol-contaminated water. However, the impact of solution chemistry on naphthol polymerization and removal has not been documented. This research investigated the impact of pH and ionic strength on peroxidase-mediated removal of 1-naphthol in completely mixed batch reactors. The impact of hydrogen peroxide to 1-naphthol ratio and activity of horseradish peroxidase was also studied. Size exclusion chromatography was used to estimate the molecular weight distribution of oligomeric products, and liquid chromatography/mass spectrometry was used to estimate product structure. Naphthol transformation decreased with ionic strength, and substrate removal was lowest at neutral pHs. Solution pH influenced the size and the composition of the oligomeric products. An equimolar ratio of H(2)O(2):naphthol was sufficient for optimal naphthol removal. Polymerization products included naphthoquinones and oligomers derived from two, three, and four naphthol molecules. Our results illustrate the importance of water chemistry when considering a peroxidase-based approach for treatment of naphthol-contaminated waters.

Gas‐Phase Study on the CC Coupling of Naphthol Catalyzed by CuII⋅TMEDA: Evidence for the Key Role of Binuclear Clusters

The mechanism of oxidative coupling of two naphthol molecules to form binaphthol catalyzed by Cu(OH)ClTMEDA (TMEDA=N,N,N',N'-tetramethylethylenediamine) was approached by means of a gas-phase model system. Concise evidence is provided that the coupling reaction proceeds in clusters with two Cu(II) centers, whereby the intermediacy of free naphthoxy radicals in the coupling step is avoided. In the absence of TMEDA, the cluster is bound via a bridging counterion and the coupling reaction is followed by cluster cleavage. The coordination of one or two TMEDA molecules to the reactive complex results in more efficient coupling of naphthol molecules, and moreover, the binuclear cluster is also conserved after the reaction is completed. The effect of TMEDA is twofold: First, it supports clustering of copper and, second, as a ligand bound to a copper center in the reactive complex, it weakens the bond between copper and the naphtholato ligand such that the naphtholato unit is more prone to undergo C--C coupling. Furthermore, a pronounced counterion effect is found that correlates well with condensed-phase data: weakly bridging counterions (e.g., NO3(-)) yield less stable dicopper clusters and the coupling reaction hardly occurs, whereas better bridging counterions (e.g., Cl(-) or Br(-)) provide more stable clusters that make the coupling reaction more efficient.

3-(tert-Butyliminomethyl)-1,1′-binaphthol ethanol solvate

The 1,1′-bi-2,2′-naphthol (BINOL) backbone of the title compound, C25H23NO2·C2H6O, indicates that it has potential in asymmetric catalysis, with the two hydroxy and the imino groups providing sites for coordination with metal ions as an O/N heterotridentate ligand. There is an intramolecular O—H...N hydrogen bond which forms a ring, and intermolecular O—H...O hydrogen bonds to the ethanol solvent molecule, which link two ethanol molecules and two naphthol molecules around a centre of symmetry.

Uncoupled oscillator model for interpreting second harmonic generation measurements of oriented chiral systems

Molecular modeling calculations of the electronically resonant nonlinear optical susceptibility of the archetypal chiral molecule binaphthol are shown to be qualitatively reproduced by considering two uncoupled naphthol molecules oriented in a manner similar to that in binaphthol. This remarkably simple uncoupled oscillator model reliably predicts the signs and relative magnitudes of the key elements within the molecular susceptibility tensor of binaphthol. These results suggest that surprisingly simple and intuitive physical models can often be constructed for qualitatively interpreting chiral-specific phenomena in nonlinear optical investigations of oriented chiral chromophores in thin films and at surfaces.

Temperature effects on excited state protolytic dissociation in aqueous solutions, micelles and liposomes: influence of phase transitions in lipid bilayers

The kinetics of the excited state protolytic dissociation of 1- and 2-naphthol, hydroxy- and chloro-substituted naphthols (ArOH) in aqueous solutions, micelles and liposomes was studied as a function of temperature (over the range 283–353 K) by using steady state and time-resolved fluorescence measurements. The fluorescence data suggest kinetic non-equivalence of ArOH undergoing excited state protolytic dissociation in liposomes. Naphthol molecules in lipid membranes can be subdivided into two main fractions which have quite different reactivities, i.e. rate constants of proton transfer. In suspensions of dipalmitoylphosphatidylcholine (DPPC) liposomes the fluorescence spectra and kinetics were complicated by incomplete solubilization of ArOH in lipid membranes. The temperature dependences of the rate constants of 1- and 2-naphthol photodissociation in water, micelles and bilayer membranes of egg lecithin are described by the Arrhenius equation. The increase in activation energy and prefactor observed in surfactant assemblies as compared with aqueous solutions can be explained by an increase in the enthalpy and entropy of the protolytic equilibrium for weak acid dissociation in less polar media. An abrupt change in the dissociation rate constant was observed near the temperature of the main phase transition in DPPC liposomes.

Molecular complexes. Part XXIII. Crystal and molecular structures of α-naphthol–1,2,4,5-tetracyanobenzene and β-naphthol–1,2,4,5-tetracyanobenzene

The crystal and molecular structures of the 1 : 1 complexes of α-naphthol and 1,2,4,5-tetracyanobenzene (I) and β-naphthol and 1,2,4,5-tetracyanobenzene (II) have been determined by Fourier methods from diffractometer data and refined by least-squares to R 0.043 for 523 reflections (I), and R 0.104 for 651 reflections (II). Both are monoclinic, space group C2/m with Z= 2 in unit cells of dimensions: (I), a= 9.250(5), b= 13.059(7), c= 6.791(4)A, β= 108.3(1)°; (II), a= 9.578(1), b= 12.754(3), c= 6.798(4)A, β= 108.13(2). The dimensions of the component molecules have been corrected for rigid-body thermal motion and are in agreement with those from previous work. The mode of donor–acceptor overlap of the molecules in the alternate plane-to-plane stacks parallel to the c axes of the crystals gives near-maximisation of the donor–acceptor charge-transfer interactions. The naphthol molecules in both structures are disordered.