Synthesis and photophysical studies of new fluorescent naphthalene chalcone.

This study reports the base-catalyzed Aldol condensation route for synthesizing a new naphthalene chalcone derivative (C1). The molecular structure of C1 was ascertained by FTIR, NMR (H and C NMR) spectroscopy, and mass spectrometry. Optical properties were explored through UV-Visible absorption and photoluminescence spectroscopy.

Effect of nanoparticle density on the kinetics of SPP-assisted plasmonic assembly.

The dynamic assembly of plasmonic metal nanoparticles (PMNPs) in an aqueous medium as a Surface-enhanced Raman spectroscopy (SERS) substrate offers advantages for analyzing liquid samples, as it generates 3-dimensional intraparticle hotspots. The surface plasmon polariton (SPP) assisted surfactant-free reversible assembly of plasmonic nanoparticles (NPs) is one of the latest methods, and it stands as a promising approach for conducting SERS measurements on molecules that demand a physiological environment. However, the assembly process is dynamic and requires a thorough analysis of the behavior of NPs in the combined forces of fluid convection and plasmonics.

Unraveling Structural and Anticancer Properties of Pyridine-Oxadiazole Derivatives: Single-Crystal XRD, Hirshfeld Analysis, and Cytotoxicity against A549 Cells.

A new series of pyridine-based 1,3,4-oxadiazole derivatives was synthesized and structurally characterized using FTIR, NMR, HRMS, and single-crystal X-ray diffraction. Hirshfeld surface analysis of the meta-methyl-substituted derivative revealed key intermolecular interactions. Cytotoxicity was evaluated against A549 lung cancer cells via MTT assay, where compound (3,5-dichloro substitution) showed the highest activity (IC = 6.

Novel Coumarin-Substituted Cyclophosphazene as a Fluorescent Probe for Highly Selective Detection of 2,4,6-Trinitrophenol.

Nitroaromatic compounds (NACs) such as 2,4,6-trinitrophenol (TNP), commonly known as picric acid (PA), hold widespread application in industries such as dyestuff production, wood preservation, explosives manufacturing, insect control, and photographic development. In this study, the organic-inorganic hybrid 4,4',4″,4‴,4″″,4‴″-((1,3,5,2λ5,4λ5,6λ5-triazatriphosphinine-2,2,4,4,6,6-hexayl)hexakis(oxy))hexakis(2-chromen-2-one) () was synthesized via the nucleophilic substitution reaction of 4-hydroxycoumarin (4-HC) with hexachlorocyclotriphosphazene (HCCP). The structure of Cpz-4-HC was fully characterized by Fourier transform infrared (FT-IR), H-, C-, and P NMR, and HRMS.

A selective bis-thiophene chalcone-based spectrofluorimetric sensor for Fe.

A highly selective bis thiophene-based chalcone as a chemosensor for detecting Fe metal ions in DMF: HO (9:1). This sensor was selective toward ferric ions over other metal ions with a detection limit in micromolar range.

Analyzing the impact of the size of fluoro and chloro substituents on induced mesomorphism in hydrogen bonded liquid crystals.

Synthesis of new supramolecules with specific properties and realistic applications requires a sound knowledge of the structure-property relationships of the synthesized molecules. Non-covalent interaction like hydrogen bonding is conducive in realizing mesomorphism. The induction of the liquid crystalline character is associated with the strength of hydrogen bonds formed between the interacting components, which are affected by the change of polarity and polarizability of both components upon change in their terminal polar substituents.

New benzisoxazole derivative: A potential corrosion inhibitor for mild steel in 0.5 M hydrochloric acid medium -insights from electrochemical and density functional theory studies.

6-fluoro-3-(4-piperidinyl)-1,2-benzisoxazole. HCl (FPBH), a substituted benzisoxazole derivative, was prepared from isonipecotic acid and characterized using various spectroscopic techniques. Using electrochemical examinations such as potentiodynamic polarisation (PDP) and electrochemical impedance spectroscopic (EIS) technique, the corrosion mitigation capabilities of this compound for mild steel (MS) in 0.

Surface-Plasmon-Polaritons for Reversible Assembly of Gold Nanoparticles, In Situ Nanogap Tuning, and SERS.

A transportable reversible assembly of gold nanoparticles (AuNPs) in an aqueous environment addresses the need for in situ surafce-enhanced Raman spectroscopy (SERS) hotspot creation for biological applications. Usually, light-directed AuNP assembly methods use higher laser powers and surfactants and are, hence, unsuitable for biological applications. Here, surface plasmon polaritons-assisted dynamic assembly of AuNPs are demonstrated at laser power density as low as 100 nW µm .

Effect of OH substitution in 3-benzylchroman-4-ones: crystallographic, CSD, DFT, FTIR, Hirshfeld surface, and energy framework analysis.

3-Benzylchroman-4-ones (homoisoflavanones) are oxygen-containing heterocycles with a sixteen-carbon skeleton. They belong to the class of naturally occurring polyphenolic flavonoids with limited occurrence in nature and possess anti-inflammatory, antibacterial, antihistaminic, antimutagenic, antiviral, and angioprotective properties. Recently, we reported the synthesis and anticancer activity studies of fifteen 3-benzylchroman-4-one molecules, and most of them were proven to be effective against BT549 and HeLa cells.

A highly sensitive surface-enhanced Raman scattering substrate prepared on a hydrophobic surface using controlled evaporation.

In the present work, we report the fabrication of a surface-enhanced Raman spectroscopy (SERS) substrate on a simple and easily fabricable hydrophobic surface. The substrates are prepared by slow and fast evaporation of a droplet of silver nanoparticle suspension in water. The corresponding identifiers for two substrates are "s_evp" and "f_evp" respectively.

Refractive index and formaldehyde sensing with silver nanocubes.

We report the synthesis of Ag nanocubes by using a sodium sulfide assisted solvothermal method. Small edge-length nanocubes (32 and 44 nm) were obtained at 145 and 155 °C reaction temperature in the synthesis process. The refractive index sensitivity of synthesized nanocubes was investigated with an aqueous solution of glucose.

Binding Motifs in the Naked Complexes of Target Amino Acids with an Excerpt of Antitumor Active Biomolecule: An Ion Vibrational Spectroscopy Assay.

The structures of proton-bound complexes of 5,7-dimethoxy-4H-chromen-4-one (1) and basic amino acids (AAs), namely, histidine (His) and lysine (Lys), have been examined by means of mass spectrometry coupled with IR ion spectroscopy and quantum chemical calculations. This selection of systems is based on the fact that 1 represents a portion of glabrescione B, a natural small molecule of promising antitumor activity, while His and Lys are protein residues lining the cavity of the alleged receptor binding site. These species are thus a model of the bioactive adduct, although clearly the isolated state of the present study bears little resemblance to the complex biological environment.

Vibronic spectra of jet-cooled 1-methyl-2(1H)-quinolinone studied by Fluorescence spectroscopy and Quantum chemical calculation.

1-methyl-2(1H)-quinolinone (MeQone) forms the framework of several hundred quinolone alkaloid molecules, both natural and synthetic, which are being used in various biological applications. In this work, we present experimental and theoretical spectroscopic investigation on the MeQone in its ground and first electronic excited states. The vibronically resolved fluorescence excitation (FE) spectrum of MeQone is recorded within 700 cm to the electronic origin under the supersonic jet-cooled condition.

Ab initio and NBO studies of methyl internal rotation in 1-methyl-2(1H)-quinolinone: effect of aromatic substitution to 1-methyl-2(1H)-pyridone.

1-methyl-2(1H)-quinolinone (MeQone) forms the framework of several hundred alkaloid molecules both natural and synthetic being used for various biological applications. From chemical structure point of view, the molecules can also be seen as an aromatic ring fused to 1-methyl-2(1H)-pyridone (1-MPY). In this work, we present theoretical investigations on internal rotation of methyl group in MeQone in light of 1-MPY.

Intermolecular dissociation energies of 1-naphthol complexes with large dispersion-energy donors: Decalins and adamantane.

The ground-state intermolecular dissociation energies D(S) of supersonic-jet cooled intermolecular complexes of 1-naphthol (1NpOH) with the bi- and tricycloalkanes trans-decalin, cis-decalin, and adamantane were measured using the stimulated-emission-pumping/resonant two-photon ionization (SEP-R2PI) method. Using UV/UV holeburning, we identified two isomers (A and B) of the adamantane and trans-decalin complexes and four isomers (A-D) of the cis-decalin complex. For 1NpOH·adamantane A and B, the D(S) values are 21.

Benchmark Experimental Gas-Phase Intermolecular Dissociation Energies by the SEP-R2PI Method.

The gas-phase ground-state dissociation energy () of an isolated and cold bimolecular complex is a fundamental measure of the intermolecular interaction strength between its constituents. Accurate values are important for the understanding of intermolecular bonding, for benchmarking high-level theoretical calculations, and for the parameterization of dispersion-corrected density functionals or force-field models that are used in fields ranging from crystallography to biochemistry. We review experimental measurements of the gas-phase () and () values of 55 different M⋅S complexes, where M is a (hetero)aromatic molecule and S is a closed-shell solvent atom or molecule.

Face, Notch, or Edge? Intermolecular dissociation energies of 1-naphthol complexes with linear molecules.

The stimulated-emission-pumping/resonant 2-photon ionization (SEP-R2PI) method was used to determine the intermolecular dissociation energies D of jet-cooled 1-naphthol(1NpOH)·S complexes, where S is a linear molecule (N, CO, CO, OCS, NO, and ethyne) or symmetric-top molecule (2-butyne) that contains double or triple bonds. The dissociation energies D(S) are bracketed as follows: 6.68 ± 0.

Intermolecular dissociation energies of hydrogen-bonded 1-naphthol complexes.

We have measured the intermolecular dissociation energies of supersonically cooled 1-naphthol (1NpOH) complexes with solvents S = furan, thiophene, 2,5-dimethylfuran, and tetrahydrofuran. The naphthol OH forms non-classical H-bonds with the aromatic -electrons of furan, thiophene, and 2,5-dimethylfuran and a classical H-bond with the tetrahydrofuran O atom. Using the stimulated-emission pumping resonant two-photon ionization method, the ground-state ( ) values were bracketed as 21.

Intermolecular dissociation energies of dispersively bound complexes of aromatics with noble gases and nitrogen.

We measured accurate intermolecular dissociation energies D of the supersonic jet-cooled complexes of 1-naphthol (1NpOH) with the noble gases Ne, Ar, Kr, and Xe and with N, using the stimulated-emission pumping resonant two-photon ionization method. The ground-state values D(S) for the 1NpOH⋅S complexes with S= Ar, Kr, Xe, and N were bracketed to be within ±3.5%; they are 5.

Elusive Sulfurous Acid: Gas-Phase Basicity and IR Signature of the Protonated Species.

The ion corresponding to protonated sulfurous acid, H3SO3(+), has been successfully delivered into the gas phase by electrospray ionization of the solution of a suitable precursor and an in-source fragmentation process. The neutral acid is a highly elusive molecule. However, its gas-phase basicity has been ascertained by means of a kinetic study of proton-transfer reactivity.

Switching on the fluorescence of 2-aminopurine by site-selective microhydration.

2-Aminopurine (2 AP) is a fluorescent isomer of adenine and has a fluorescence lifetime of ~11 ns in water. It is widely used in biochemical settings as a site-specific fluorescent probe of DNA and RNA structure and base-flipping and -folding. These assays assume that 2 AP is intrinsically strongly fluorescent.

Building up water-wire clusters: isomer-selective ultraviolet and infrared spectra of jet-cooled 2-aminopurine (H2O)n, n = 2 and 3.

2-Aminopurine (2AP) is an adenine analogue with a high fluorescence quantum yield in water solution, which renders it a useful real-time probe of DNA structure. We report the ultraviolet (UV) and infrared (IR) spectra of size-selected and jet-cooled 9H-2AP·(H2O)n clusters with n = 2 and 3. Mass- and species-specific UV/UV holeburning spectroscopy allows to separate the UV spectra of four cluster isomers in the 31,200–33,000 cm(–1) spectral region with electronic band origins at 31339, 31450, 31891, and 32163 cm(–1).

Isomer- and species-selective infrared spectroscopy of jet-cooled 7H- and 9H-2-aminopurine and 2-aminopurine·H2O clusters.

The infrared (IR) spectra of the supersonic-jet cooled 9H- and 7H-tautomers of 2-aminopurine (2AP) and of the 9H-2-aminopurine·H(2)O monohydrate clusters have been measured by mass- and species-selective IR-UV double resonance spectroscopy in the 3200-3900 cm(-1) region, covering the N-H and O-H stretching vibrations. The spectra are complemented by density functional (B3LYP and PW91) and by second-order Møller-Plesset (MP2) calculations of the electronic energies and vibrational frequenciesof the respective 2AP tautomers and clusters. The 9H- and 7H-2-aminopurine tautomers were definitively identified by the shifts of their NH and NH(2) symmetric and asymmetric stretching frequencies and by comparison to the B3LYP/TZVP calculated IR spectra.

Diagnosing the protonation site of b2 peptide fragment ions using IRMPD in the X-H (X = O, N, and C) stretching region.

Charge-directed fragmentation has been shown to be the prevalent dissociation step for protonated peptides under the low-energy activation (eV) regime. Thus, the determination of the ion structure and, in particular, the characterization of the protonation site(s) of peptides and their fragments is a key approach to substantiate and refine peptide fragmentation mechanisms. Here we report on the characterization of the protonation site of oxazolone b(2) ions formed in collision-induced dissociation (CID) of the doubly protonated tryptic model-peptide YIGSR.