Effect Of Nitrogen Insertion Research Articles

Development of Dithienosilole-Pyridalthiadiazole-Based Copolymer as an Electron Donor in Organic Photovoltaic Cells

The effect of nitrogen insertion in a benzothiadiazole (BT) moiety was investigated via the synthesis of a novel copolymer based on dithienosilole (DTS) and pyridalthiadiazole (PT), the heterocyclic counterpart. Stille cross coupling of the electron rich and electron poor units yields poly[(4, 4’-didodecyldithieno[3, 2-b:2’, 3’-d]silole-2, 6-diyl)- alt -(2, 1, 3-pyridalthiadiazole-4, 7-diyl), a nonsoluble polymer. Dense π–π stacking interactions that inhibited polymer solubility were cured by the introduction of two solubilizing hexylthiophene spacers, and a new soluble low-bandgap copolymer, namely poly[(4, 4’-didodecyldithieno[3, 2-b:2’, 3’-d]silole-2, 6-diyl)- alt -{4, 7-bis[2-(3-hexyl)thienyl]-2, 1, 3-pyridalthiadiazole-5, 5’-diyl}] (PDTSDTPT), was alternatively obtained. For reasons of comparison, the corresponding oligomer, i.e., ODTSDTPT, was also synthesized. Their chemical, thermal, optical, electrical, and electrochemical properties were investigated. UV–visible spectroscopy revealed that PDTSDTPT alternating copolymer is more absorbing than its BT analog. It has a lower optical bandgap, higher absorptivity, and red-shifted absorption spectrum into the near-infrared region up to 900 nm. Photovoltaic applicability was investigated for PDTSDTPT and its derived oligomer in bulk heterojunction solar cells employing PC 60BM, [6,6]-phenyl-C60 butyric acid methyl ester, as the n-type semiconductor. Significant improvement of open-circuit voltage was evidenced with PT-based materials. The short-circuit current ( J SC) and fill factor ( FF ), however, remain a material of continuous improvement by morphology control.

Naphtho[2,1-h]isoquinolines: a new class of partially reduced polycyclic aromatic nucleus

An efficient de novo synthesis of partially reduced naphtho[2,1-h]isoquinolines has been developed through base catalyzed ring transformation of 2-oxo-4-sec-amino-5,6-dihydro-2H-benzo[h]chromene-3-carbonitriles by a carbanion, generated in situ from 1-substituted-4-piperidones in DMF and powdered KOH, in excellent yields. The effect of nitrogen insertion in the D ring of partially reduced benzo[c]phenanthrene on conformational changes has also been studied by X-ray diffraction analysis.

Effect of nitrogen insertion on the antitussive properties of menthol and camphor

Aromatic vapors of monoterpenoids such as menthol and camphor are known to possess antitussive effects for the symptomatic relief of upper respiratory tract. The lactams 10 and 11 of menthol and camphor, respectively, have been synthesised and evaluated first time for their antitussive activity in citric acid-induced cough in guinea pig model. The effect of nitrogen insertion in the chemical architecture of menthol and camphor on the antitussive activity was reflected by the significant decrease of the cough frequency and increase in the cough latency exhibited by aerosolized 10 and 11. Prior exposure of aerolsolised 10 for 5 min at different concentrations (15, 30, and 60 μg/l) significantly reduced cough response induced by citric acid and also increased latency to initial cough response. Similarly 11 has showed greater inhibitory cough response in comparison to camphor at concentrations such as 125, 250, and 500 μg/l. However, latency to initial cough response was only increased at the concentrations of 250 and 500 μg/l.

The effect of nitrogen insertion on the magnetic and structural properties of Sm2–xGdxFe17 alloys (0 ≤ x ≤ 2)

AbstractThe effect of nitrogen insertion on the structural and magnetic properties of Sm2–xGdxFe17Ny compounds (x = 0‐2) has been investigated. X‐ray diffraction patterns at room temperature show that all our synthesized samples are single phase and crystallize in the rhombohedral Th2Zn17‐type structure with very small amount of impurity. Nitrogen insertion leads to a monotonic increase in the unit cell volume, it leads also to an increase in the Curie temperature Tc from 425 K for SmGdFe17 to 760 K for SmGdFe17N3. Moreover, the nitrogen insertion increases the saturated magnetization Ms. Ms increases from 17.9 µB/mole for SmGdFe17 to 32.7 µB/mole for SmGdFe17N3. X‐ray diffraction measurements on magnetically aligned powder samples of Sm2–xGdxFe17Ny reveal a change in the easy magnetization direction from planar before nitrogen insertion to the c‐axis after nitrogen insertion. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Crystallographic and magnetic properties of a new rare‐earth iron nitride Nd2–xSmxFe17Ny (y ∼ 3)

AbstractThe effect of nitrogen insertion on the structural and magnetic properties of Nd2–xSmxFe17 metallic alloys has been investigated. X‐ray powder diffraction characterizations show that all the nitrides are single phase and crystallize in the Th2Zn17‐type structure. The lattice parameters of the Nd2–xSmxFe17Ny compounds decrease with samarium content. Magnetization studies show that all the samples are ferromagnetic at room temperature. Nitrogen insertion leads to an increase of the Curie temperature Tc. Tc is found to increase from 370 K for NdSmFe17 to 760 K for NdSmFe17N2.8. It leads also to an increase of the saturation magnetization Ms. $ { {{\rm M}_{\rm s}({\rm y}) - {\rm M}_{\rm s}(0)} \over {{\rm M}_{\rm s}(0)} } $ decreases with increasing samarium content from 58% for x = 0 to 45% for x = 2. X‐ray diffraction characterizations on magnetically aligned powder samples of Nd2–xSmxFe17Ny reveal a change in the easy magnetization direction from planar for x = 0 to c axis for x = 2. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Magnetic and structural properties of Sm 1.5 Gd 0.5 Fe 17−x Co x N y with 0 ≤ x ≤ 3 and y ≈ 3

The effect of nitrogen insertion on the structural and magnetic properties of (Sm 1 . 5 Gd 0 . 5 )Fe 1 7 - x Co x compounds has been investigated. X-ray powder diffraction analysis shows that all the nitrides are single phase and crystallize in the Th 2 Zn 1 7 -type structure. The lattice parameters of the (Sm/Gd) 2 Fe 1 7 - x Co x N y compounds increase with increasing x. Magnetization studies indicate that all the samples are ferromagnetic at room temperature. Nitrogen insertion leads to an increase in the Curie temperature T c from 520 K for Sm 1 . 5 Gd 0 . 5 Fe 1 6 Co to 880 K for Sm 1 . 5 Gd 0 . 5 Fe 1 6 CoN 2 . 9 . Moreover, the nitrogen insertion increases the saturated magnetization M s . M s increases from 107.67 emu/g for x = 0 to 149.92 emu/g for y = 3. X-ray diffraction measurements on magnetically aligned powder samples of Sm 1 . 5 Gd 0 . 5 Fe 1 7 - x Co x N y reveal a change in the easy magnetization direction from planar to conical after nitrogen insertion.

The effect of nitrogen insertion in the Nd 2− xGd xFe 17N y gadolinium substituted compounds

The structural and magnetic properties of Nd 2− x Gd x Fe 17N y ( x=0–2 and y≈3) gadolinium substituted compounds were studied. X-Ray diffraction characterization showed that all our samples are single phase and crystallize in the rhombohedral Th 2Zn 17-type structure. Nitrogen insertion in Nd 2− x Gd x Fe 17 samples induced an increase in the unit-cell volume. This increase was found to be about 5.6% for all gadolinium contents. Magnetization measurements showed that nitrogen insertion induced a strong increase in the Curie temperature, Δ T c= T cy− T c0, which depends on the gadolinium content. The values of Δ T c decrease with increasing gadolinium concentration. It was found to decrease from 125% for x=0 to 70% for x=2. Nitrogen insertion leads to an increase in the saturated magnetization, μ s( y)− μ s(0)/ μ s(0), which increases with increasing gadolinium content. It was found to increase from 26% for x=0 to 53% for x=2. The volume effects on the Curie temperature of our samples have been studied. The evolution of Grüneisen parameter defined by Γ versus gadolinium contents was linear.

X-ray absorption spectroscopy and magnetic circular x-ray dichroism in

The effect of nitrogen insertion on the electronic properties of cerium and iron in has been studied by means of x-ray absorption spectroscopy (XAS) and magnetic circular x-ray dichroism (MCXD). The evolution of the electronic structure of cerium upon nitrogen insertion has been studied. It emerges from this MCXD study at the edges of cerium that the cerium atoms bear a 5d magnetic moment of about that is coupled antiferromagnetically to that of iron. The spin polarized EXAFS signal has been observed; an attempt to evidence the magnetic environment has been made in the light of previous neutron diffraction results. Comparison of EXAFS and spin polarized EXAFS is revealed to be an efficient new tool to distinguish between magnetic and non-magnetic atoms in the environment of the absorber. The analysis of the Fe K edge MCXD spectra shows that insertion of nitrogen induces a trend to strong ferromagnetism with an almost completely filled majority spin subband.

Neutron powder-diffraction study of Pr2Fe17 and Pr2Fe17N2.9.

We report on the effect of nitrogen insertion on the crystal structure of ${\mathrm{Pr}}_{2}$${\mathrm{Fe}}_{17}$. The influence of nitrogen uptake was studied by a neutron powder-diffraction experiment performed at 2, 300, and 655 K. A comparison is made between ${\mathrm{Pr}}_{2}$${\mathrm{Fe}}_{17}$ and the nitride ${\mathrm{Pr}}_{2}$${\mathrm{Fe}}_{17}$${\mathrm{N}}_{2.9}$. The nitride is found to retain the host-metal symmetry over the whole temperature range. The nitrogen atoms fill almost completely the site 9e (space group R3m) and their coordination can be described as a distorted octahedron (${\mathrm{Fe}}_{4}$${\mathrm{Pr}}_{2}$). The change in the environment of the Pr atom induced by nitrogenation is analyzed in terms of the coordination number, bond length, and electronegativity of the nearest surrounding atoms. The values for the magnetic moment of Pr and Fe in ${\mathrm{Pr}}_{2}$${\mathrm{Fe}}_{17}$ and ${\mathrm{Pr}}_{2}$${\mathrm{Fe}}_{17}$${\mathrm{N}}_{2.9}$ have been refined in the present work.