Cinchona Alkaloid Derivatives modified Fe3O4 Nanoparticles for Enantioselective Ring Opening of meso- Cyclic Anhydrides

In the present work, the molecular framework of the quinidine was modified at the methoxy functional of C6’ carbon of quinoline moiety with a long-chain carboxylic acid group (-COOH) and...

Seasonal Differences in Submicron Marine Aerosol Particle Organic Composition in the North Atlantic

Submicron atmospheric primary marine aerosol (aPMA) were collected during four North Atlantic Aerosol and Marine Ecosystem Study (NAAMES) research cruises between November 2015 and March 2018. The average organic functional group (OFG) composition of the aPMA samples was 72–85% hydroxyl group mass, 6–13% alkane group mass, and 5–8% amine group mass, which is similar to prior observations and to aerosol generated from Sea Sweep. The carboxylic acid group had seasonal averages that ranged from 1% for Winter, 8% for Late Spring, and 10% for Autumn. The carboxylic acid group mass concentration correlated with nitrate mass concentration and weakly with photosynthetically active radiation (PAR) above 100 W m–2, suggesting a substantial secondary organic aerosol contribution in sunnier months. The three sizes of aPMA aerosol particles (<0.18, <0.5, and <1 μm) had the same four organic functional groups (hydroxyl, alkane, amine, and carboxylic acid groups). The aPMA spectra of the three sizes showed more variability (higher standard deviations of cosine similarity) within each size than between the sizes. The ratio of organic mass (OM) to sodium (OM/Na) of submicron generated primary marine aerosol (gPMA) was larger for Autumn with project average of 0.93 ± 0.3 compared to 0.55 ± 0.27 for Winter, 0.47 ± 0.16 for Late Spring, and 0.53 ± 0.24 for Early Spring. When the gPMA samples were separated by latitude (47–60°N and 18–47°N), the median OM/Na concentration ratio for Autumn was higher than the other seasons by more than the project standard deviations for latitudes north of 47°N but not for those south of 47°N, indicating that the seasonal differences are stronger at higher latitudes. However, the high variability of day-to-day differences in aPMA and gPMA composition within each season meant that seasonal trends in organic composition were generally not statistically distinguishable.

Colorimetric Studies on the Interaction of Quinhydrone with Monosodium Glutamate (MSG) in Aqueous Medium

The interaction of quinhydrone with monosodium glutamate (MSG) in aqueous medium has been investigated using colorimetric method at different pH conditions. Quinhydrone is a mixture of quinone and hydroquinone. In acidic pH, hydroquinone is dominating and the hydroxyl group of hydroquinone interacts with the amino/carboxylic acid group of glutamate ion due to hydrogen bonds thus influences the solution. While in alkaline pH, the colour of the quinhydrone is brown due to benzoquinone being dominating component and can interact with amino group of glutamate ion thus resulting in the formation of di-anilido-quinone. This will lead to an increase of intensity of quinhydrone solution. Glutamate being amphoteric in nature, provides an option to examine it in both acidic and alkaline pH. The effectiveness of detection of MSG in alkaline medium is better due to its favourable interactions.

Cerium photocatalyzed radical smiles rearrangement of 2-aryloxybenzoic acids

Visible light-driven CeCl3-mediated aryl migration from an aryl ether to a carboxylic acid group through radical-Smiles rearrangement is reported.

Synthesis of bis-azobenzene derivatives with reactive bromohexyl unit and carboxylic acid group based on Disperse Yellow 7

In this work, two types of azobenzene derivatives based on Disperse Yellow 7 (DY7, 4-[4-(phenylazo)phenylazo]-o-cresol) were synthesized, which are bis-azobenzenes bearing flexible functional 6-bromohexyl chain or carboxylic acid moiety. The first one was synthesized by alkylation of DY7 with an excess of 1,6-dibromohexane in the presence of a mild base (K2CO3). The second one (azo dye with carboxylic acid functionality) was obtained by the alkaline hydrolysis of the ester bond of the newly obtained DY7 derivative with the ethoxycarbonyl group. The synthesized compounds were characterized by different spectral analytical techniques such as 1H NMR, 13C NMR, FT-IR, and UV-Vis. They can be employed for the synthesis of a wide variety of azo-based materials, which may be suitable for photochromic systems and molecular electronics applications.

Synthesis of Levofloxacin Derivatives with some Amines and their Complexes with Copper(II) Salts and Evaluation of their Biological Activity

Levofloxacin belongs to the fluoroquinolone family; it is a potent broad-spectrum bactericidal agent. The pharmacophore required for significant antibacterial activity is the C-3 carboxylic acid group and the 4-pyridine ring with the C-4 carbonyl group, into which binding to the DNA bases occur. In this work, we tried to show that by masking the carboxyl group through amide formation using certain amines to form levofloxacin carboxamides, an interesting activity is kept. Levofloxacin carboxamides on the C-3 group were prepared, followed by the formation of their copper complexes. The target compounds were characterized by FT-IR, elemental analysis. The antimicrobial activity of the target compounds was evaluated and showed satisfactory results compared with levofloxacin. This has indicated that the presence of the carbonyl of C-3 carboxyl moiety is not essential, as levofloxacin carboxamides showed interesting copper complexes indicating that they retain the activity of levofloxacin, since its activity depends on binding to DNA gyrase via magnesium binding.

The Importance of Solid-state Molecular Motion to Room Temperature Phosphorescence

<div>Molecular motion is often considered detrimental to luminescence because it favors nonradiative decay. However, nothing is absolute, and molecular motion can also do useful work if utilized properly. For example, photothermal therapy makes use of the heat generated in light irradiation for cancer treatment. To further explore the merits of molecular motion, ortho-substituted benzoic acids were used as model compounds to evaluate the importance of molecular motion to luminescence in the solid state. It is verified that the twisting of the carboxylic acid group can activate spin vibronic coupling to facilitate intersystem crossing to result in more efficient room temperature phosphorescence (RTP). A five-state model is established to understand the ISC process and an effective pre-twisted molecular design strategy is put forward for the development of efficient RTP materials.</div>

The Importance of Solid-state Molecular Motion to Room Temperature Phosphorescence

<div>Molecular motion is often considered detrimental to luminescence because it favors nonradiative decay. However, nothing is absolute, and molecular motion can also do useful work if utilized properly. For example, photothermal therapy makes use of the heat generated in light irradiation for cancer treatment. To further explore the merits of molecular motion, ortho-substituted benzoic acids were used as model compounds to evaluate the importance of molecular motion to luminescence in the solid state. It is verified that the twisting of the carboxylic acid group can activate spin vibronic coupling to facilitate intersystem crossing to result in more efficient room temperature phosphorescence (RTP). A five-state model is established to understand the ISC process and an effective pre-twisted molecular design strategy is put forward for the development of efficient RTP materials.</div>

The Importance of Solid-state Molecular Motion to Luminescence in Solid State

<div>Molecular motion is often considered detrimental to luminescence because it favors nonradiative decay. However, nothing is absolute, and molecular motion can also do useful work if utilized properly. For example, photothermal therapy makes use of the heat generated in light irradiation for cancer treatment. To further explore the merits of molecular motion, ortho-substituted benzoic acids were used as model compounds to evaluate the importance of molecular motion to luminescence in the solid state. It is verified that the twisting of the carboxylic acid group can activate spin vibronic coupling to facilitate intersystem crossing to result in more efficient room temperature phosphorescence (RTP). A five-state model is established to understand the ISC process and an effective pre-twisted molecular design strategy is put forward for the development of efficient RTP materials.</div>