N-methylformamide Research Articles

Vibrational and electronic studies on interactions of Cu (II) with protic amides: Structural aspects of biological importance

Raman, IR and UV–Vis–NIR experiments of formamide (FA), N-methylformamide (NMF) and their solutions with copper perchlorate at different compositions were carried out. The downshift of the νCO mode and the upshift of the νCN vibration have been observed for both amides and suggest that an ionic structure is stabilized by Cu (II). The quantitative Raman study at the νCN region reveals that six FA molecules are coordinated to Cu (II) while four NMF molecules are around the metal ion. The data are complemented by information at the region characteristic of the metal–ligand vibrations, which evidences coordination through the O atom. The spectral changes observed at the νCN region have been then combined to the electronic data and show that [Cu(FA)6]2+ and [Cu(NMF)4]2+ are described as distorted octahedral and square planar complexes.

Study of N-methylcarbamoylated hemoglobin in blood of being an exposure biomarker of N, N-dimethylformamide

To assess the value of blood N-methylcarbamoylated haemoglobin (NMHb) as a biomarker of N, N-dimethylformamide (DMF) exposure. Seventy-two DMF processing workers in a synthetic leather factory were included in the DMF exposure group, and 12 workers in a food factory without exposure to DMF were included in the control group. Long-time individual sampling in workplace was performed among 45 workers in the exposure group, accompanied by a questionnaire survey. Blood and urine were collected for the determination of urinary N-methylformamide (NMF), urinary creatinine, and blood NMHb. Air DMF and urinary NMF were determined by gas chromatography. NMHb in blood was degraded to 3-methyl-5-isopropylhydantoin by Edman degradation before it could be determined by gas chromatography/mass spectrometry. Air DMF in workplace and NMF in post-shift urine were both correlated with NMHb in blood, and the respective regression equations were LgNMHb (nmol/g globin) = 0.32×LgDMF (mg/m(3))+1.8 (r = 0.60, P < 0.005), and LgNMHb (nmol/g globin) = 0.47×LgNMF (mg/g Cr) + 1.4 (r = 0.56, P < 0.005). NMHb can be used as a biomarker of long-term exposure to DMF.

Volumetric Properties of Binary Mixtures of 1-Butyl-1-Methylpyrrolidinium Tris(pentafluoroethyl)trifluorophosphate with N-Methylformamide, N-Ethylformamide, N,N-Dimethylformamide, N,N-Dibutylformamide, and N,N-Dimethylacetamide from (293.15 to 323.15) K

Experimental densities of binary mixtures of ionic liquid 1-butyl-1-methylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate ([BMPYR][FAP]) with two protic amides—N-methylformamide (NMF) and N-ethylformamide (NEF)—and three aprotic—N,N-dimethylformamide (DMF), N,N-dibutylformamide (DBF), and N,N-dimethylacetamide (DMA)—are reported in the temperature range from (293.15 to 323.15) K and at atmospheric pressure (0.1 MPa) over the whole composition range. This ionic liquid was selected due to its hydrophobic properties and hydrolytic stability. The excess molar volumes derived from the experimental densities appear to be positive for all of the studied mixtures in the whole composition range at all temperatures. The systems with aprotic amides (DMF, DBF, DMA) show higher values of excess molar volume compared to those with protic amides (NMF, NEF), while the number of the methyl groups at the carbon atom does not affect the composition corresponding to the maximum of the excess molar volume.

Influence of the composition of water–organic mixtures and of organic solvents properties on solvation of glycyl-L-tyrosine at 298.15 K

Enthalpies of dissolution of glycyl-L-tyrosine in the mixtures of water with methanol (MeOH), ethanol (EtOH), propanol (1-PrOH), 2-propanol (2-PrOH), acetonitrile (AN), 1,4-dioxane (DO),acetone (AN), dimethylsulfoxide (DMSO), formamide (FA), N-methylformamide (NMF), N,N-dimethylformamide (DMF) and N,N-dimethylacetamide (DMA) have been measured at 298.15K. The standard enthalpies of the solution (ΔsolH∘) and transfer (ΔtrH∘) of glycol-L-tyrosine from water into aqueous solution of organic co-solvents as well as the enthalpy coefficients of pairwise interaction (hxy) have been calculated. The interrelation between the enthalpy characteristics of dissolution (transfer) of glycyl-L-tyrosine and the composition of aqueous organic mixtures was established. Contributions of the organic co-solvent properties (molar volume, cohesion energy density, dipolarity/polarizability, acidity and basicity) to the energy of pairwise interactions were estimated quantitatively by means of a modified Kamlet–Taft equation. Some characteristics of intermolecular interactions of glycyl-L-tyrosine with the molecules of organic co-solvents with the analogous characteristics of glycylglycine and diglycylglycine were compared.

On the hydrogen bonding between N-methylformamide and acetone and tetrahydrofuran

Liquid mixtures of N-methylformamide (NMF)–acetone (ACT) and NMF–tetrahydrofuran (THF) 20mol% NMF have been investigated using Monte Carlo simulations, aiming to obtain new details on the hydrogen bonding donation of the peptide bond in non-aqueous media. There are strong evidences of the H-bonding between NMF and each of the solvents, but the results indicate significant differences between the H-bond interactions in each mixture. THF solvates better the amide than ACT. The NMF–THF H-bonds are more directed and the structure of the solvation shell is much more ordered in the NMF–THF mixture than in the NMF–ACT one.

Solvent-Induced Bond Rearrangement in Two Zn(II) Coordination Polymers and The Single-Crystal- to-Single- Crystal Transformation

Two new zinc coordination polymers are synthesized at the present of the different solvent. Complex [Zn(pbc)2]n (1) and complex [Zn(pbc)· (DMF)]n (2) (Hpbc = 3-pyrid-3-ylbenzoic acid, DMF = N,N-dimethyl formamide and NMF = N-methyl formamide) are isomers with one-dimensional frameworks, but the resulting Zn(II) coordination numbers are different. The single-crystal-to-single-crystal transformation appears between complexes 1 and 2.

Transport properties of ammonium nitrate in N-methylformamide and N,N-dimethylformamide

In this work transport properties of ammonium nitrate in N-methylformamide (NMF) and N,N-dimethylformamide (DMF) were investigated in order to explain the nature of solute–solvent interactions in diluted and concentrated ammonium nitrate solutions. The electrical conductivity was measured in the wide ammonium nitrate molality range in the temperature range from 303.15K up to 348.15K. Obtained results are compared with those obtained for the solutions of ammonium nitrate in formamide (FA). The molar conductivity of studied mixtures is also calculated, as well as dissociation constants of ammonium nitrate in FA, NMF and DMF.

Volumetric properties of ammonium nitrate in N-methylformamide

The volumetric properties (apparent molar volumes and partial molar volumes) of ammonium nitrate in N-methylformamide (NMF) have been evaluated from the density data and discussed in the term of respective ionic and dipole interactions. The densities of the NMF+ammonium nitrate mixtures were measured at T=308.15 to 348.15 K for different ammonium nitrate molalities in the range from 0 to 8.4624 mol·kg−1. The apparent molar expansibility and the coefficients of thermal expansion were also calculated. The results were compared with those obtained for DMF+ammonium nitrate mixtures.

Liquid-phase synthesis of a Li3PS4 solid electrolyte using N-methylformamide for all-solid-state lithium batteries

A Li3PS4 solid electrolyte was directly synthesized from Li2S and P2S5 by a liquid-phase reaction using N-methylformamide (NMF) and n-hexane as reaction media. After the reaction of Li2S and P2S5, a yellow NMF solution was obtained. The NMF solution was dried at 180 °C for 3 hours under vacuum to remove NMF and to obtain a powder. A crystalline phase of the obtained powder from the NMF solution was attributed to Li3PS4 crystals, and the ionic conductivity of the obtained powder was 2.3 × 10−6 S cm−1 at 25 °C. Electrode–electrolyte composite materials for all-solid-state lithium batteries were prepared by coating the Li3PS4 solid electrolyte onto LiCoO2 particles using the NMF solution. SEM and EDX analysis showed that LiCoO2 particles were uniformly coated with the Li3PS4 solid electrolyte. An all-solid-state cell using the LiCoO2 particles coated with the Li3PS4 solid electrolyte as a positive electrode operated as a secondary battery.

Occupational exposure to N,N-dimethylformamide in the summer and winter.

We evaluated total body burden of N,N-dimethylformamide (DMF) taken through the lung and skin by personal exposure of workers to DMF and urinalysis of N-methylformamide (NMF) and N-acetyl-S(N-methylcarbamoyl)-cysteine (AMCC). A total of 270 workers were engaged in four different jobs in a workplace distant from main production lines emanating high levels of DMF. They were not required to wear any personal protective equipment including respirators or gloves. We found that log-transformed urinary levels of NMF and AMCC increased with an increase in log-transformed concentrations of exposure to DMF. Urinary levels of NMF and AMCC were significantly higher in the summer than the winter, although there was no significant seasonal difference in the concentrations of exposure to DMF. Our findings suggested that the increased urinary levels of NMF and AMCC in the summer resulted in increased skin absorption of DMF due to an increased amount of DMF absorbed by the moisturized skin under humid and hot conditions. Seasonal changes in the relative internal exposure index confirmed the present finding of enhanced summertime skin absorption of DMF. AMCC is thought to be a useful biomarker for assessments of cumulative exposure to DMF over a workweek and for evaluations of workers’ health effects.

Synthesis of monolithic zirconia with macroporous bicontinuous structure via epoxide-driven sol–gel process accompanied by phase separation

Monolithic macroporous zirconia was synthesized through a new method involving an epoxide-driven sol–gel method accompanied by a spontaneous phase separation. The sol–gel transition utilized inorganic salt ZrCl4 as primary precursor and propylene oxide as matrix former through a ring-opening reaction. Phase separation was induced with poly-(ethylene oxide) (PEO) and its tendency was adjusted by incorporating Mg2+/Y3+ and N-methylformamide (NFA) in starting solution. The morphology of the dried gel changed from a solid nanoporous structure through a phase separated macroporous bicontinuous structure to aggregates particles when varying Mg2+ or Y3+, NFA and PEO composition. An appropriate choice of the starting composition, by which the phase separation and gelation occurred parallel, allows the fabrication of macroporous zirconia monoliths in large dimensions (Φ = 30 mm, h = 8 mm). The skeleton of the monolithic macroporous zirconia gels possess a BET surface area of 271.7 m2/g. Accordingly, the effect and mechanisms of Mg2+, Y3+ and NFA during gelation process were proposed in detail. Moreover, Mg2+ or Y3+ might also act as stabilizer to form the magnesia or yttria stabilized tetragonal or cubic zirconia after the samples were heat-treated at high temperature (800 °C).

Biosynthesis of Nitrogenase Metalloclusters

Biosynthesis of Nitrogenase Metalloclusters

Densitometric and spectroscopic investigation of interactions of selected N-substituted amides and acetonitrile

The paper reports the results of densitometric and FTIR spectroscopic study of the interactions of N-methylformamide, N-ethylformamide and N-ethylacetamide with acetonitrile. Excess molar volumes, VmE, of N-methylformamide (NMF)+acetonitrile, N-ethylformamide (NEF)+acetonitrile, N-ethylacetamide (NEA)+acetonitrile have been determined at the temperatures: 298.15K, 303.15K, 308.15. Excess molar volumes were fitted with Redlich–Kister equation. The spectroscopic characteristics for NH⋯N hydrogen bonded complex and equilibrium constant for 1:1 complex formation, at 25°C were determined by using IR measurements. The results have been discussed in terms of hydrogen bonding. Spectroscopic results confirm the assumptions related to the volume contractions of examined binary mixtures.

Role of Anions (Tetrafluoroborate, Perchlorate) of Tetrabutylammonium Salts in Determining Solvation Effects Prevailing in Industrially Essential Solvents Probed by Conductance and FT-IR Spectra

Molecular interactions of tetrabutylammonium salts prevailing in organic solvent media have been analyzed, both qualitatively and quantitatively, using conductometric studies and validating the results with Fourier transform infrared (FT-IR) measurements. From conductometric studies of tetrabutylammonium tetrafluoroborate [Bu4NBF4] and tetrabutylammonium perchlorate [Bu4NClO4] in nitromethane (NM), N-methyl formamide (NMF), and formamide (FA) at 298.15 K, it is revealed that high molecular interaction is mainly because of ion–dipole interactions, which is evidenced from the FT-IR measurements. The 1978 Fuoss conductance-concentration equation in terms of the limiting molar conductance (Λo), the association constant (KA), and the association diameter (R) was used to interpret the conductance data. Tetrabutylammonium tetraphenylborate [Bu4NBPh4] as the “reference electrolyte” was used to estimate the ionic contributions to the limiting molar conductance. The degree of interaction is articulated in terms of the association constant (KA), which illustrates that viscosity of the solvent plays an important role in the ion–dipole interaction.The ionic interaction obtained is highest in the case of [Bu4NBF4] and FA in comparison to the other systems. The consequences have been considered in terms of dipole–dipole interactions, hydrogen bond formation, structural feature, and configurational theory. The FT-IR spectroscopic studies of the variational intensity of characteristic bands of the solvents have been undertaken, and the solvation phenomenon is evidenced by the change of band intensities owing to the occurrence of the electrolytes.

국내 합성피혁제조업 근로자에 대한 디메틸포름아미드의 공기중 농도와 생물학적 노출지표간의 상관성 평가

The possibility of acute hepatotoxicity caused by dimethylformamide (DMF) requires regular monitoring of the workers who are using DMF to prevent the occupational disease. The authors performed ambient and biological monitoring of workers involved in synthetic leather manufacturing processes using DMF to assess the correlation between the markers of ambient and biological monitoring of DMF. The authors monitored 142 workers occupationally exposed to DMF from 19 workshops in the synthetic leather and ink manufacturing industries located in northern region of Gyeonggi-do. The subjects answered questionnaire on work procedure and use of personal protective equipment to be classified by exposure type. DMF in air samples collected using personal air samplers, diffusive and active sampler, was analysed using gas chromatograph-flame ionization detector (GC-FID) with DB-FFAP column (length 30 m, i.d. 0.25 mm, film thickness 0.25 <TEX>${\mu}m$</TEX>). Urinary N-methylformamide (NMF) was analysed using gas chromatograph-mass selective detector (GC-MSD) at selected ion monitoring (SIM) mode with DB-624 column (length 60 m, i.d. 0.25 mm, film thickness 1.40 <TEX>${\mu}m$</TEX>). Geometric mean (GM) and geometric standard deviation (GSD) of the ambient DMF was <TEX>$6.85{\pm}3.43$</TEX> ppm, and GM and GSD of urinary NMF was <TEX>$42.3{\pm}2.7$</TEX> mg/L. The ratio of subjects with DMF level over 10 ppm was 44%, and those with urinary NMF over 15 mg/L was 87%. NMF in urine adjusted by DMF in air was <TEX>$4.61{\pm}2.57$</TEX> mg/L/ppm and <TEX>$9.50{\pm}2.41$</TEX> mg/L/ppm, respectively, with or without respirator. There was seasonal differences of NMF in urine adjusted by DMF in air, <TEX>$7.63{\pm}2.74$</TEX> mg/L/ppm in summer and <TEX>$4.53{\pm}2.29$</TEX> mg/L/ppm in winter. The urinary NMF concentration which corresponds to 10 ppm of ambient DMF was 52.7 mg/L (r=0.650, n=128). Considering the difference of the route of exposure which resulted from the compliance of wearing personal protective equipment, the estimated contribution of respiratory and dermal exposure route for DMF was 48.5% vs. 51.5%.

Preparation of Li2S–P2S5 solid electrolyte from N-methylformamide solution and application for all-solid-state lithium battery

Electrode–solid electrolyte composite materials for all-solid-state lithium batteries were prepared by coating of the Li2S–P2S5 solid electrolyte onto LiCoO2 particles using a N-methylformamide (NMF) solution of 80Li2S·20P2S5 (mol%) solid electrolyte. SEM and EDX analysis showed that the Li2S–P2S5 solid electrolyte was uniformly coated on LiCoO2 particles. The all-solid-state cell using the LiCoO2 particles coated with the solid electrolyte showed higher charge–discharge capacity than the cells using uncoated LiCoO2 particles.

Nanomaterials Based on Polyanilines and MoSe2

Polyaniline, poly(N-methyl aniline), poly(2-ethyl aniline) and poly(2-propyl aniline) were intercalated into layered molybdenum diselenide by using the exfoliation/restacking property of LixMoSe2. MoSe2 was reacted with n-butyllithium to form LixMoSe2. The LixMoSe2 was exfoliated in N-methylformamide (NMF) with the help of ultrasonication which lead to the formation of single layers of MoSe2. Addition of NMF solutions of the polymers to the exfoliated layers resulted in their intercalation into MoSe2. The products were characterized by powder X-ray diffraction. Fourier transform infra-red spectroscopy, and four-probe van der Pauw technique electrical conductivity measurements are reported here for the first time.

Hepatotoxicity in Rats Treated with Dimethylformamide or Toluene or Both

The effects of toluene in dimethylformamide (DMF)-induced hepatotoxicity were investigated with respect to the induction of cytochrome P-450 (CYP) and the activities of related enzymes. The rats were treated intraperitoneally with the organic solvents in olive oil (Single treatment groups: 450 [D1], 900 [D2], 1,800 [D3] mg DMF, and 346 mg toluene [T] per kg of body weight; Combined treatment groups: D1+T, D2+T, and D3+T) once a day for three days, while the control group received just the olive oil. Each group consisted of 4 rats. The activities of the xenobiotic metabolic enzymes and the hepatic morphology were assessed. The immunoblots indicated that the expression of CYP2E1 was considerably enhanced depending on the dosage of DMF and the CYP2E1 blot densities were significantly increased after treatment with both DMF and toluene, compared to treatment with DMF alone. The activities of glutathione- S-transferase and glutathione peroxidase were either decreased or remained unaltered after treatment with DMF and toluene, whereas the lipid peroxide levels were increased with increasing dosage of DMF and toluene. The liver tissue in the D3 group (1,800 mg/kg of DMF) showed signs of microvacuolation in the central vein region and a large necrotic zone around the central vein, in rats treated with both DMF (1,800 mg/kg) and toluene (D3T). These results suggest that the expression of CYP2E1 is induced by DMF and enhanced by toluene. These changes may have facilitated the accelerated formation of Nmethylformamide (NMF) from toluene, and the generated NMF may directly induce liver damage.

Acoustic, volumetric and spectroscopic properties of formamide + N-methylformamide + 2-chloroethanol at different temperatures

The ultrasonic velocity () and density () of ternary mixture of formamide (FA) + N-methylformamide (NMF) + 2-chloroethanol (2-CletOH) have been measured at temperatures 298.15, 308.15 and 318.15 K, over the entire composition range. From the experimental values of ultrasonic velocity and density, adiabatic compressibility (), intermolecular free length (), molar sound velocity (), molar compressibility () and specific acoustic impedance () have been calculated. The excess values of ultrasonic velocity (), adiabatic compressibility () and molar volume () were also calculated. Further, the infrared spectra have been recorded at room temperature (298.15 K) and found to be useful for understanding the presence of extensive hydrogen bonding between oxygen atom of C=O group of FA and NMF molecules and hydrogen atom of the H–O group of 2-CletOH molecule in the present liquid mixture.

Acoustic, volumetric and spectroscopic investigations in binary mixtures of formamide/N-methylformamide + 2-chloroethanol at various temperatures

The ultrasonic velocity (u) and density (ρ) of binary liquid mixtures of formamide (FA) and N-methylformamide (NMF) with 2-chloroethanol (2-CletOH) have been measured at temperatures 298.15, 308.15 and 318.15K, over the entire composition range. From the experimental values of ultrasonic velocity and density, the various acoustical parameters have been evaluated. The excess values of ultrasonic velocity (uE), adiabatic compressibility (βSE) and molar volume (VmE) were also calculated. Further, the infrared spectra of both of the systems, FA+2-CletOH and NMF+2-CletOH, have been recorded at room temperature (298.15K).