Thermal Decomposition of Neodymium Amide Complexes

The decomposition of NdCl₃ L(L = N,N-dimethylformamide [DMF] or N,N-dimethyacetamide [DMA]) compounds has been investigated by thermogravimetric and differential thermal analysis (TGA and DTA) coupled with Fourier transform infrared (FTIR) spectroscopy. When heated in air, the NdCl₃L compounds decompose by a mechanism involving oxidation of the amide ligand to CO₂ and HCl. Some free armide is also released in the thermal decomposition in air. However, when heated under nitrogen, clean release of DMA or DMF is observed. In both cases, the amide is released two steps. From 30 to 40% of the amide is initially released with little or no associated enthalpy as measured by DTA. As the temperature is increased, the remaining 60 to 70% of the amide is released via an endothermic process. The enthalpy for this release is 53.1 - 3.8 kJ/mole for DMF and 40.9 - 1.1 kJ/mole for DMA, suggesting that DMF binds more strongly to Nd(III) than does DMA. Steric effects caused by the additional methyl group in DMA might be responsible for the weaker binding of this amide compared to DMF.     

Analysis of amides in the air by sampling with SPME and detection by GC-FID

This paper proposes a solid-phase microextraction (SPME) method for the passive sampling and determination of N,N-dimethylacetamide (DMA) and N,N-dimethylformamide (DMF) in air by capillary GC with flame ionization detection. The optimized conditions for SPME method were grab sampling, polydimethylsiloxane/divinylbenzene fiber, extraction for 90 min at 25 +/- 2 degrees C, desorption for 3 min at 220 degrees C, and relative humidity 45 +/- 2%. Under these conditions, the method presented good linearity (R = 0.996), repeatability (%RSD 2.79 and 9.85 for DMF and DMA, respectively), and detection limit (0.021 and 0.024 mg/m3 for DMF and DMA, respectively).     

The micellar behavior of linear triblock terpolymers of styrene (S), isoprene (I), and methyl methacrylate (MMA) in selective solvents for PS and PMMA

A series of linear triblock terpolymers consisting of polystyrene (PS), polyisoprene (PI) and poly(methyl methacrylate) (PMMA) were examined in tetrahydrofuran (THF), a good solvent for all the blocks and in dimethylacetamide (DMA) and dimethylformamide (DMF), selective solvents for PS and PMMA. In DMA and DMF, which are both non-solvents for PI, multimolecular micelles were formed. The micelles were characterized by low-angle laser light scattering (LALLS), dynamic light scattering (DLS) and viscometry. The aggregation number of the triblock terpolymers was greater in DMF than in DMA, reflecting the higher non-solvent strength of DMF for PI. The aggregation number was also found to increase with increasing PI content of the terpolymers in both DMA and DMF. The hydrodynamic radii depended on the aggregation number of the micelle and the length of the corona forming PS and PMMA blocks. The complexity involved in studying a system consisting of three different polymer blocks is discussed in the context of the results obtained.     

Synthesis and inhibition profiles of N-benzyl- and N-allyl aniline derivatives against carbonic anhydrase and acetylcholinesterase – A molecular docking study

The alkyl and aryl derivatives of aniline are important starting materials in fine organic synthesis. Allyl bromide and benzyl chloride were taken as substrates for the alkylation reaction and as a halide ion scavenger. Triethylamine was utilized at reflux condition of N,N-dimethylacetamide (DMA). Novel synthesized N-benzyl and N-allyl aniline derivatives (1a-f) were evaluated to be highly potent inhibitors for acetylcholinesterase (AChE) and carbonic anhydrases (hCAs). The half maximal inhibitory concentration (IC₅₀) of N-benzyl- and N-allyl aniline derivatives were calculated between 243.11 and 633.54 nM for hCA I, 296.32–518.37 nM for hCA II and 182.45–520.21 nM for AChE enzymes. On the other hand, K_i values are in the range of 149.24 ± 15.59 to 519.59 ± 102.27 nM for AChE, 202.12 ± 16.21 to 635.31 ± 45.33 nM for hCA I and 298.57 ± 94.13 to 511.18 ± 115.98 nM for hCA II isoenzyme. Additionally, in silico molecular docking computations were performed with Autodock Vina program to support the experimental in vitro studies for both hCAs and AChE inhibitors. The in silico molecular docking results demonstrated that the scores are in good agreement with the experimental results.     

Improving the Sensitivity of Fluorescent Microsphere Immunoassays for the Simultaneous Detection of Foodborne Pathogens Using Dimethylacetamide

The liquid-chip assay is a new method for detecting bacterial surface antigens. This assay conjugated self-prepared monoclonal antibodies against Escherichia coli O157:H7, Listeria monocytogenes, Staphylococcus aureus, and Salmonella enterica serovar Typhi with carboxylated fluorescent microspheres based on the double-antibody sandwich principle. This experiment used dimethylacetamide (DMAC) as the solvent to dissolve 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC) and N-hydroxysulfosuccinimide (S-NHS) during conjugation. The modified liquid-chip assay was used to simultaneously detect the four foodborne pathogens. The sensitivity of the assay using the new conjugation method was also evaluated. The limits of detection for E. coli O157:H7, L. monocytogenes, S. aureus, and S. typhi during multiplex detection using the improved method were 0.25, 0.25, 0.5, and 0.25 cfu/mL, respectively, whereas those using the traditional method were 0.5, 0.5, 1, and 0.5 cfu/mL, respectively. Therefore, the improved method is reliable and effectively improves the detection sensitivity of liquid-chip assays.     

Formation of ATP by Photochemical Excitation of Benzoquinones in Dimethylacetamide Solution

A new method of adenosine triphosphate production is described which involves photo‐excitation of p‐benzoquinones under the presence of adenosine diphosphate and inorganic phosphate in N,N‐dimethylacetamide solution. A possible mechanism for the reaction is presented.