Naphthalene Groups Research Articles

Synthesis and electrochemical properties of bis(dipyrrinato)zinc complex derivatives

Naphthalene group with 1- or 2-link position was substituted into 5-position of dipyrrinato zinc complex and bis[5-(1-naphthalenyl)-dipyrrinato]zinc complex (Zn(1-NaPN) 2) and bis[5-(2-naphthalenyl)-dipyrrinato]zinc complex (Zn(2-NaPN) 2), which are the derivatives of bis(dipyrrinato)zinc complex, were successfully synthesized. The optical properties of the synthesized compounds were measured through UV-visible and PL spectrum. UV-visible maximum values in solution state, 485 and 486 nm for Zn(1-NaPN) 2 and Zn(2-NaPN) 2 have similar absorption maximum value and PL spectrum maximum values are 516 and 518 nm, respectively. In the film state, UV-visible maximum values, about 517 nm for both compounds, also indicated absorption of similar wavelengths. PL spectrum was shown to be about 550 nm which is also red-shifted about 33 nm from the solution state, moving toward yellowish green color. Zn(1-NaPN) 2 and Zn(2-NaPN) 2, the synthesized compounds, were measured on electrochemical kinetic properties through cyclic voltammogram (CV), and both materials showed similar oxidation voltage of about 0.7 V (vs. Ag/AgNO 3). The exponent of scan rate and x-value of Zn(1-NaPN) 2 and Zn(2-NaPN) 2 were 0.52 and 0.33, so the kinetics of Zn(1-NaPN) 2 is mainly controlled by diffusion process.

Novel organosoluable aromatic polyimides derived from unsymmetrical 1,3-bis(4-aminophenoxy)naphthalene and aromatic dianhydrides

A novel unsymmetrical diamine, 1,3-bis(4-aminophenoxy)naphthalene, was prepared through the nucleophilic displacement of 1,3-dihydroxynaphthalene with p-fluoronitrobenzene in the presence of potassium carbonate, followed by catalytic reduction with hydrazine. A series of novel aromatic polyimides containing bis(phenoxy)naphthalene units were synthesized from the unsymmetrical diamine and a range of aromatic tetracarboxylic dianhydrides via the usual two-step procedures that included ring-opening polyaddition and thermal/chemical cyclodehydration. The poly(amic acid)s had inherent viscosities ranging from 0.65 to 2.01 dL/g. All the poly(amic acid)s could be converted thermally into transparent, flexible, and tough polyimide films. Most of the polyimides were soluble in organic solvents, such as dimethylacetamide, N-methyl-2-pyrrolidone, m-cresol, or o-chlorophenol due to the unsymmetrical and bulky pendant naphthalene groups. The tensile strength and elongation at break of the polyimide films ranged from 74 to 97 MPa and 4 to 7%, respectively. These polyimides had glass transition temperatures ranging from 221 to 312 °C. Thermogravimetric analysis revealed these polymers to be fairly stable up to 500 °C, and the 10% weight loss temperature were recorded in the range of 531–580 °C in nitrogen and 522–570 °C in air. The substituted position effect of bis(phenoxy)naphthalene on the properties of the polyimides were investigated. The polyimides derived from unsymmetrical 1,3-substituted bis(4-aminophenoxy) naphthalene showed better solubility without sacrificing their thermal and mechanical properties due to the unsymmetrical and bulky pendant effects.

Discovery and Mechanistic Study of a Class of Protein Arginine Methylation Inhibitors

Protein arginine methylation regulates multiple biological processes such as chromatin remodeling and RNA splicing. Malfunction of protein arginine methyltransferases (PRMTs) is correlated with many human diseases. Thus, small molecule inhibitors of protein arginine methylation are of great potential for therapeutic development. Herein, we report a type of compound that blocks PRMT1-mediated arginine methylation at micromolar potency through a unique mechanism. Most of the discovered compounds bear naphthalene and sulfonate groups and are structurally different from typical PRMT substrates, for example, histone H4 and glycine- and arginine-rich sequences. To elucidate the molecular basis of inhibition, we conducted a variety of kinetic and biophysical assays. The combined data reveal that this type of naphthyl-sulfo (NS) molecule directly targets the substrates but not PRMTs for the observed inhibition. We also found that suramin effectively inhibited PRMT1 activity. These findings about novel PRMT inhibitors and their unique inhibition mechanism provide a new way for chemical regulation of protein arginine methylation.

α-Lipoic Acid Alters Post-Translational Modifications and Protects the Chaperone Activity of Lens α-Crystallin in Naphthalene-Induced Cataract

Purpose: To evaluate whether α-lipoic acid (LA) inhibits lens opacity of naphthalene-induced cataract by altering post-translational modifications (PTMs) and protecting the chaperone activity of α-crystallins.Methods: Forty-five Sprague-Dawley rats were divided into three groups: control, naphthalene, and naphthalene plus LA. Cataracts were induced by oral administration of 1 g naphthalene/kg body weight/day. Rats in the naphthalene plus LA group were also fed 30 mg LA/day. The development of naphthalene-initiated cataract was monitored every week by slit lamp microscopy for nine weeks, then the lens proteins were separated by HPLC, and peaks corresponding to α-crystallins were resolved on 2-DE. The spots of 2-DE were subjected to mass spectrometry to identify PTMs. Chaperone activity of α-crystallins was measured by heat-induced aggregation of βL-crystallin.Results: The lenses of rats fed with naphthalene plus LA exhibited less light scattering than that fed with only naphthalene at three weeks after treatment (P < 0.01). C-terminal truncated αA crystallin was detected in naphthalene-induced cataract and was abrogated by LA treatment. Several other post-translational modifications were identified including methylation, phosphorylation, acetylation, carbamylation, and oxidation.Conclusions: Our data are the first to show PTM changes induced by naphthalene in rat lenses. Our findings also indicate that LA can inhibit naphthalene-induced lens opacity by altering PTM and protecting the chaperone activity of α-crystallins.

Trans-Tetraaquabis{(E)-2-cyano-1-[(ethoxycarbonyl)methylsulfanyl]-2-(1-naphthylaminocarbonyl)ethene-1-thiolato}calcium(II) diethyl ether disolvate

In the title compound, [Ca(C18H15N2O3S2)(H2O)4]·2C4H10O, the Ca atom, which lies on an inversion centre, is coordinated octa­hedrally by four water mol­ecules and two anions of the ketene dithio­acetal, the donor atoms of which are the amidic carbonyl O atoms. The central backbone of the ligands (excluding the naphthalene and oxoethyl groups) is essentially planar (r.m.s. deviation 0.035 Å). Intra­molecular hydrogen bonds are observed from the NH group to the formally ‘thiol­ate’ S atom and from one coordinated water to the nitrile group and to the ether O atom. Inter­molecular hydrogen bonds from the second independent water mol­ecule to the thiol­ate S atom and the side-chain oxo group connect the mol­ecules in chains parallel to the a axis.

Fluorescence light emission at 1 eV from a conjugated polymer

While polymer light-emitting diodes are currently finding commercial applications in displays and lighting, the development of low bandgap polymers emitting in the infrared has received much less attention in spite of potential applications for instance in the field of communication technologies. We report here a light emission at 1 eV from a low bandgap polymer made of an alternation of dialkoxy-phenylene units and a low bandgap monomer composed of an electron accepting 2-thia-1,3,5,8-tetraaza-cyclopenta[ b]naphthalene group fenced with electron donating thiophene units. The electronic structure of the polymer chains has been characterized at a quantum-chemical level to shed light into the experimental results.

Protective effect of aqueous garlic extract against naphthalene-induced oxidative stress in mice

The aim of this study was to investigate the possible protective effects of aqueous garlic extract (AGE) against naphthalene-induced oxidative changes in liver, kidney, lung and brain of mice. Balb/c mice (25-30 g) of either sex were divided into five groups each comprising 10 animals. Mice received for 30 days: 0.9% NaCl, i.p. (control); corn oil, i.p; AGE in a dose of 125 mg kg-1, i.p.; naphthalene in a dose of 100 mg kg-1, i.p. (dissolved in corn oil); and AGE (in a dose of 125 mg kg-1, i.p.) plus naphthalene (in a dose of 100 mg kg-1, i.p.). After decapitation, liver, kidney, lung and brain tissues were excised. Malondialdehyde (MDA) and glutathione (GSH) levels and myeloperoxidase activity (MPO) were determined in the tissues, while oxidant-induced tissue fibrosis was determined by collagen content. Tissues were also examined microscopically. Serum aspartate aminotransferase, alanine aminotransferase levels and blood urea nitrogen and creatinine concentrations were measured for the evaluation of hepatic and renal function, respectively. MDA and GSH levels were also assayed in serum samples. In the naphthalene-treated group, GSH levels decreased significantly, while MDA levels, MPO activity and collagen content increased in the tissues (P<0.01-0.001), suggesting oxidative organ damage, which was also verified histologically. In the AGE-treated naphthalene group, all of these oxidant responses were reversed significantly (P<0.05-0.01). Hepatic and renal function test parameters, which increased significantly (P<0.001) following naphthalene administration, decreased (P<0.05-0.001) after AGE treatment. The results demonstrate the role of oxidative mechanisms in naphthalene-induced tissue damage. The antioxidant properties of AGE ameliorated oxidative organ injury due to naphthalene toxicity.

Optical and electrochemical investigation of diaminonaphthalene derivatives

A series of diaminonaphthalene derivatives with naphthalene as a core and butylamino and phenylamino as substituted groups were synthesized and their optical and electrochemical behavior were investigated. Phenylamino substituted naphthalene derivatives exhibit two absorption bands, which are assigned to n → π* electronic transitions that are due to electron transfer from nitrogen lone pairs to the π* orbital of the naphthalene group and the phenyl group, respectively. Comparing with butylamino substitutes, phenylated ones exhibit a red-shift in both absorption and emission for their electron-donating phenyl groups. The fluorescence quantum yields of the molecules were measured in THF. Cyclic voltammetric measurements demonstrated that the diaminonaphthalene derivatives possess two oxidation processes and the solid-state ionization potentials were estimated from the electrochemical potential. The phenylamino-naphthalenes possess higher ionization potentials than those of the alkylated ones. The relative HOMO and LUMO levels for these materials, important parameters for the design of efficient organic light-emitting or photovoltaic devices, were assessed through electrochemical and spectroscopic measurements.

The synthesis, light-harvesting, and photocatalysis of naphthylporphyrin-functionalized platinum nanocomposites

A tetraphenylporphyrin bearing four naphthalene donor moieties (5,10,15,20-tetrakis(4-(naphthalen-1-ylmethoxy)phenyl)porphyrin were synthesized and characterized using 1H NMR, FTIR, UV–vis, FL, TEM, and XRD. Substituting the naphthalene groups onto the porphyrin ring led the molecule to absorb over a broader range (200–700 nm) and to undergo efficient intramolecular energy transfer from the naphthalene to the porphyrin ring. FTIR, XRD and TEM analyses indicated that within a functionalized platinum nanocomposite comprising the porphyrin, the photoreceptive dye forms a shell containing a nanosize Pt core (∼2.8 nm). The photocatalytic activity of the Pt nanocomposite towards water reduction to hydrogen was >twice that of a Pt-naphthalene-free porphyrin system. The turnover numbers (TON Pt and TON dye) and quantum yields of hydrogen ( Φ H 2 ) were 72, 7200 and 3.0%, respectively, calculated on the basis of the total amount of H 2 evolved after 12 h irradiation.

Spectroscopic characterisation of the inclusion complexes between the antifungal drugs naftifine and terbinafine and cyclodextrins

The complexation of naftifine (NF) and terbinafine (TB) with cyclodextrins (CDs) has been investigated by UV/visible and 1H NMR spectroscopy, ROESY techniques and also ESI-MS. Both drugs form 1:1 inclusion complexes with all the CDs tested except with α-CD, as deduced from the Benesi–Hildebrand plots and confirmed by ESI-MS and NMR spectroscopy (Job plot method). The K 11 values for NF decrease in the order β-CD > methylated β-CD > 2-hydroxypropyl-β-CD >γ-CD. The determination of the enthalpy and entropy provides information about the main driving forces in the process. The stability constants of the complexes NF–β-CD, TB–β-CD and TB–γ-CD determined by 1H NMR spectroscopy are in agreement with the values obtained by UV. For TB–β-CD, the value is higher, due to the fact that the length of the TB aliphatic chain allows a deeper inclusion of the naphthalene group inside the corresponding β-CD molecule, according to the 2D ROESY experiments.

Identification and Characterization of Binding Sites on S100A7, a Participant in Cancer and Inflammation Pathways

S100A7 (psoriasin) is a member of the S100 family of signaling proteins. It is implicated in and considered a therapeutic target for inflammation and cancer, yet no small molecule ligands for S100A7 have been identified. To begin the development of specific small molecule inhibitors of S100A7 function, we have used a series of surface binding fluorescent dyes to probe the surface hydrophobic sites. Two naphthalene-based dyes (2,6-ANS and 1,8-ANS) were found to bind S100A7 in a distinct cleft. We characterized the binding interaction by determining both the structure of S100A7 bound to 2,6-ANS and the structure of S100A7 bound to 1,8-ANS to 1.6 A. In both cases, two molecules of dye were docked such that the naphthalene groups were positioned in two symmetry-related grooves that are formed by the N-terminal helices of each monomer. We observed that Met12 acts as a gatekeeper to the binding cleft, adopting an "open" conformation for the more elongated 2,6-ANS while remaining in a "closed" conformation for the more compact 1,8-ANS. Steady-state fluorescence experiments revealed that S100A7 binds two copies of 2,6-ANS, each with a K(d) of 125 muM. Time-resolved fluorescence lifetime measurements indicated that the two molecules of 2,6-ANS bind in two independent binding sites with different fluorescence lifetimes, suggesting that the S100A7 homodimer is not perfectly symmetric in solution. Isothermal titration calorimetry studies demonstrate that S100A7 has a higher affinity for 2,6-ANS than 1,8-ANS. Yeast two-hybrid studies were also used to probe contributions of individual residues of an S100A7 triple mutant with respect to Jab1 binding. Mutation of Leu78, which forms part of the Met12 cleft occupied by 2,6-ANS, reduced the level of Jab1 binding, suggesting a potentially important role for the Met12 hydrophobic pocket in defining a Jab1 interface. Additional Y2H studies also delineate contributions of Gln88 and in particular Asp56 that shows the most significant abrogated binding to Jab1. Collectively, these data suggest a complex interaction between S100A7 and the much larger Jab1. These studies form the basis for the development of small molecule reporters and modifiers of S100A7 form and function.

A Vibrational Raman Optical Activity Study of 1,1′‐Binaphthyl Derivatives

The Raman polarized and vibrational Raman optical activity (VROA) backward spectra are simulated for a series of 2,2'-substituted 1,1'-binaphthyl compounds presenting a variety of torsion angles between the two naphthalene rings. The substitution prevents free rotation along this torsion angle and the chirality of these compounds is thus called atropisomerism. However, the rotation is not completely frozen so that two different conformations, namely cisoid and transoid, are found and their Raman and VROA signatures are studied. As expected, the Raman spectra are not very sensitive whereas the VROA spectra present more complex patterns, which evolve as a function of the torsion angle between the two naphthalene groups. In particular, our analysis shows that some modes can be used as a probe for the determination of the torsion angle of these molecules in solution. The contributions of both invariants to the VROA backward intensity are also assessed.

Synthesis and Structure Determination of S,S′-(Naphthalen-2-ylmethyl sulfanyl (1-p-tolyl-ethylidene) Hydrazine

AbstractS,S′-(Naphthalen-2-ylmethyl sulfanyl (1-p-tolyl-ethylidene) hydrazine (SNM4MA) was prepared by the condensation of S-napthalen-2-ylmethyldithiocarbazate (SNMDTC) and 4-methylacetophenone. Yellow needles of SNM4MA were obtained upon slow evaporation of a 50:50 mixture of acetonitrile and DMSO over a period of weeks. The compound crystallizes in the monoclinic system with the space group C 2/c and Z = 4. The unit cell parameters are a = 7.0221(2) A, b = 22.8428(6) A, c = 23.5127(6) A with β = 94.0222(13)°. Single crystal X-ray analysis shows that the molecule has crystallographic two-fold rotational symmetry coincident with the S-S bond. The title compound exists as a trans-cis conformer in which the naphthalene group is trans with respect to the thione sulfur while the benzyl group adopts a cis geometry. 13 C and 1 H spectra confirm that the dimeric nature is retained in DMSO solution.Graphical AbstractSingle crystal X-ray analysis of S,S′-(naphthalen-2-ylmethyl sulfanyl (1-p-tolyl-ethylidene) hydrazine shows that the molecule is dimeric with a two-fold rotational symmetry coincident with the S-S bond via both the thione sulfur atoms. The molecule was found to retain its dimeric structure in dimethylsulfoxide solution.[IMAGE]

Design and synthesis of thiourea based receptor containing naphthalene as oxalate selective sensor

The thiourea based receptor containing naphthalene groups (1), has been successfully designed and synthesized for application as an oxalate receptor. A density functional theory at B3LYP/6-31G(d,p) level of theory has been applied to predict the binding ability between 1 and selected anions, i.e., oxalate, malonate, succinate, glutarate, dihydrogen phosphate, and hydrogen sulphate. Calculation results point out that receptor 1 shows the strongest interaction to oxalate ion with the binding free energy of 172.48 kcal mol(-1). The recognition ability of 1 to the selected anions has been also investigated by means of the absorption and emission techniques. Experimental results are in excellent agreement with the calculation data in which receptor 1 shows highly selective for oxalate ion over the other anions with logbeta of 3.82 (0.02) M(-1) by means of the size of binding cavity.

Effects of the Pendant Naphthalene Group on the Mechanical Properties and Low Temperature Shape Memory Effect of Polyurethane Copolymer

A series of shape memory polyurethane (SMPU) attached by pendant naphthalenes along the polyurethane (PU) chains was prepared. The SMPU chain was composed of 4,4'-methylenebis(phenylisocyanate) (MDI), poly(tetramethyleneglycol)-2000, 1,4-butanediol (BD) as a chain extender, and glycerol. The naphthalene was connected to the glycerol moiety of the PU chain using the second MDI as a connecting agent. The key point was whether the pendant naphthalene would improve the mechanical properties and shape recovery at subzero temperature. Similar mechanical properties (maximum stress and strain at break) and shape recovery, compared to the previous SMPUs, were attained at temperature above Tm, but a contrasting difference was observed in the shape recovery at subzero temperature. The conventional SMPU was not able to return to the original shape below -10°C, but the developed SMPU recovered its original shape even at -30°C. The reason for the exceptional shape recovery at both low temperature and ambient temperature is sought from a structural viewpoint.

(E)-2-{(2-Hydroxynaphthalen-1-yl)methylene}hydrazinecarboxamide

In the title mol­ecule, C12H11N3O2, the dihedral angle between the mean planes of the naphthalene and carboxamide groups is 28.9 (8)°. The hydrazine N atoms are twisted slightly out of the plane of the carboxamide group [C—C—N—N torsion angle = −175.06 (13)°]. The crystal packing is influenced by N—H⋯O hydrogen bonding which includes a bifurcated hydrogen bond between the amide N atom and nearby carboxyl and hydroxyl O atoms. A second bifurcated hydrogen bond occurs between the hydroxyl O atom and nearby amide (inter­molecular) and hydrazine (intra­molecular) N atoms. As a result, mol­ecules are linked into a co-operative hydrogen-bonded network of infinite one-dimensional O—H⋯O—H⋯O—H chains along the (101) plane of the unit cell in a zigzag pattern, the dihedral angle between the mean planes of the naphthalene groups of adjacent mol­ecules in the chain being 86.9 (2)°. A MOPAC PM3 calculation provides support to these observations.

Surface-enhanced fluorescence and surface-enhanced Raman scattering of ultrathin layers of bichromophoric antenna systems adsorbed on silver nanoisland films

We investigated a novel bichromophoric antenna system, characterized by energy transfer between a naphthalene group acting as the donor and a benzofurazane group acting as the acceptor. We studied the spectroscopic properties (infrared, Raman, UV–vis and fluorescence) of self-assembled monolayers of this molecular antenna on Ag nanoisland films and the energy-transfer process upon irradiation at 300 nm.

Synthesis and Crystal Structure of 5-[2-(6-bromonaphthalenyloxymethyl)]-3-(4-morpholinomethyl)-1,3,4-oxadiazole-2(3H)-thione

The title compound, C18H18BrN3O3S, a derivative of 1,3,4-oxadiazole, crystallizes in the triclinic space group P-1 with unit cell parameters a = 6.8731(3), b = 8.9994(4), c = 15.7099(6) A, α = 92.779(3)°, β = 130.575(3)°, γ = 107.868(4)°, Z = 2. The dihedral angle between the mean planes of the planar naphthyl and morpholine (chair) rings with the planar oxadiazol ring is 50.1(8) and 76.8(6)°, respectively. The planar naphthyl ring is twisted 52.2(5)° with the mean plane of the morpholine ring. A group of four intermolecular close contacts are observed between a bromine atom and hydrogen atoms from the closely packed naphthyl, morpholine and oxy–methyl groups in the unit cell. These molecular interactions in concert with an additional series of π–π stacking interactions that occur between the center of gravity of the two 6-membered rings of the naphthalene group influence the twist angles of each of these three groups. A MOPAC AM1 calculation of the conformation energy of the crystal structure [226.0128(9) kcal] compared to that of the minimum energy structure after geometry optimization [29.9744(1) kcal] reveals a significantly reduced value. The twist angles of the three groups above also change after the AM1 calculation giving support to the influence of both intermolecular C–H···Br short-range interactions and Cg π–π stacking interactions on these angles which therefore play a role in stabilizing crystal packing. Crystal structure of 5-{[(6-bromonaphthalen-2-yl)oxy]methyl}-3-(morpholin-4-ylmethyl)-1,3,4-oxadiazole-2(3H)-thione, C18H18BrN3O3S, is reported and its geometric and packing parameters described and compared to a MOPAC computational calculation.

Synthesis and characterization of poly(ether ketone ether ketone ketone)/poly(ether ether ketone ketone) copolymers containing naphthalene and pendant cyano groups

Abstract2,6‐Bis(β‐naphthoxy)benzonitrile (BNOBN) was synthesized by reaction of β‐naphthol with 2,6‐difluorobenzonitrile in N‐methyl‐2‐pyrrolidone (NMP) in the presence of KOH and K2CO3. Poly(ether ketone ether ketone ketone)(PEKEKK) /poly(ether ether ketone ketone) (PEEKK) copolymers containing naphthalene and pendant cyano groups were obtained by electrophilic Friedel‐Crafts polycondensation of terephthaloyl chloride (TPC) with varying mole proportions of 4,4′‐diphenoxybenzophenone (DPOBP) and 2,6‐bis(β‐naphthoxy)benzonitrile (BNOBN) using 1,2‐dichloroethane (DCE) as solvent and NMP as Lewis base in the presence of anhydrous AlCl3. The resulting polymers were characterized by various analytical techniques, such as FTIR, DSC, TG, and WAXD. The results indicated that the crystallinity and melting temperature of the polymers decreased with increase in concentration of the BNOBN units in the polymer, the glass transition temperature of the polymers increased with increase in concentration of the BNOBN units in the polymer. Thermogravimetric studies showed that all the polymers were stable up to 536°C in N2 atmosphere. The copolymers have good resistance to acidity, alkali, and organic solvents. Because of the melting temperature (Tm) depression with increase in the BNOBN content in the reaction system, the processability of the resultant coplymers could be effectively improved. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Förster resonance energy transfer (FRET) with a donor–acceptor system adsorbed on silver or gold nanoisland films

We observed Förster resonance energy transfer (FRET) with a covalently linked donor-acceptor pair D-A consisting of two naphthalene groups acting as the donors and a benzofurazan group acting as the acceptor and adsorbed onto Ag or Au nanoisland films. The use of metal nanoisland films, which caused a strong enhancement of the Raman signal, permitted description of the adsorption mechanism onto the two metals. The intense fluorescence response of molecular adsorbates and the different behavior of the antenna on Ag and Au nanoislands are partly explained in terms of the radiating plasmon model.