The electrical properties of some 2-aminopyrimidine and 2-aminopyrazine schiff bases

Mounir, Mohamed; Darwish, K. A.; El-Ansary, A. L.; Hassib, H.B.

doi:10.1016/0040-6031(87)80046-1

Cited by 11 publications

(5 citation statements)

References 2 publications

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“…The shallow behavior observed in most of the ligands can be attributed to enolketo tautomerism [46]. Therefore, the first step in the conduction process is delocalization of -electrons while the second step involves excitation of an electron from the highest-filled -molecular orbitals to the lowest unfilled ones [47]. The log values with low ÁE values obtained for the ligands can be ascribed to intermolecular hydrogen bond formation between the hydroxyl and the azo groups [48].…”

Section: Resultsmentioning

confidence: 93%

Synthesis and Characterization of New Azopyrimidine Complexes

Soayed¹,

Masoud²,

Sharsherh³

et al. 2003

Journal of Coordination Chemistry

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New azo compounds containing barbituric acid, thiobarbituric acid or thiouracil, together with their complexes, were prepared. All the complexes are tetrahedral. Axial ESR spectra were observed for the complexes with a d x2Ày2 ground state with small g || values indicating strong interaction between the ligands and their metal ions. Conductivity measurements proved semiconducting properties for the ligands and their complexes. Energies of activation (ÁE a) and order of the thermal reactions (n) were calculated by DTA.

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Section: Resultsmentioning

confidence: 93%

Synthesis and Characterization of New Azopyrimidine Complexes

Soayed¹,

Masoud²,

Sharsherh³

et al. 2003

Journal of Coordination Chemistry

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“…This may in turn cause electronic localization and thus inhibit the electronic migration within the molecule [23]. The deduced AE values at higher temperatures for unsubstituted sample la is generally higher than for substituted samples lb-lh.…”

Section: Resultsmentioning

confidence: 95%

“…In addition, most of the compounds have two activation energy values corresponding to two conduction modes (see Table I). Discontinuity in the semiconducting region can be ascribed to a molecular rearrangement [23]. For the ohydroxy derivative lb the relatively high AE 1 values can be attributed to phase transition in the compound rather than electron thermal agitation occuring due to heating [24].…”

Section: Resultsmentioning

confidence: 99%

Electrical, spectral and thermochromic properties of some hydrazone derivatives

Salem

Issa

Ayad

et al. 1994

J Mater Sci: Mater Electron

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The electrical and spectral properties of some ethyl cyanoacetate phenylhydrazone derivatives have been investigated. Results obtained show anomalous metallic-like and semiconducting behaviours corresponding to the low and higher temperature ranges. At high temperatures a positive temperature coefficient of electrical conductivity (d~/d T) provides evidence for the semiconducting character, and the linear correlation indicates metallic-like behaviour at a low temperature range. Values of activation energy (AE) were calculated in each case. In addition, the current-voltage dependence of the hydrazone derivatives was investigated. This showed that the compounds under study have ohmic conduction. The correlation between Xma x and Hammett constant was also investigated. The hydrazone derivatives are thermolabile and undergo thermochromic behaviour during heating.

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“…The temperature rise facilitates the segmental motion of the polymer chains, so the molecular chains with different mobilities try to adjust and align themselves in such a way to increase the density of the dipole orientations to add to the polarization of the system and improving the dielectric loss values. 38,39 Furthermore, a single peak only is observed for the pure PMMA and Ni@SiO2/PMMA nanocomposite samples, this peak is at the same temperature for all nanocomposite concentrations at the same frequency, however, it shifts toward higher temperature for the higher frequencies. For the pure PMMA, this peak begins at 120 C for 10KHz, however it begins at 80 C at 10 KHz for all the nanocomposite samples.…”

Section: Electrical Propertiesmentioning

confidence: 93%

Dielectric and mechanical properties of nickel silica core-shell reinforced PMMA nanocomposites

Abulyazied

Abomostafa

2021

Journal of Composite Materials

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This paper study the dielectric and mechanical properties of poly (methyl methacrylate)-nickel silica core-shell nanocomposite. Ni@SiO2/PMMA nanocomposite films were prepared by incorporating Ni@SiO2 nanoparticles in PMMA matrix using the solution casting method. The morphology of the prepared nanoparticles was examined through a High-resolution transition electron microscope (HRTEM), which revealed the formation of SiO2 shell at Ni magnetic nanoparticles. The dielectric properties of the nanocomposite films were studied as a function of temperature and frequency in the ranges of 30–180°C and 100 Hz – 5 MHz respectively. The incorporation of the nano Ni@SiO2 to PMMA has a positive effect on the dielectric constant ε′ of the nanocomposites, as well as, ε′ improved with increasing temperature. The real electric modulus (M′) of composites confirms the occurrence of dispersion in all composites at all temperatures. While dielectric loss tangent ε ″ and the loss part of electric modulus spectra (M) exhibit relaxation peaks which characterize possible relaxation of interfacial polarization in the interface between Ni@SiO2 core-shell and PMMA matrix, these peaks have shifted towards higher frequency with temperature. The relaxation and activation energies, Ec and Ea values decreased from 0.49 to 0.40 eV and from 0.87 to 0.70 eV respectively as Ni@SiO2 content increased. The ac conductivity of the nanocomposite films has deeply increased with increasing temperature and Ni@SiO2 content. The longitudinal modulus (L), shear modulus (G), Young's modulus (E), and bulk modulus (B) of films were studied and they increased as the filler increased from 0 to 15 wt.%.

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The electrical properties of some 2-aminopyrimidine and 2-aminopyrazine schiff bases

Cited by 11 publications

References 2 publications

Synthesis and Characterization of New Azopyrimidine Complexes

Synthesis and Characterization of New Azopyrimidine Complexes

Electrical, spectral and thermochromic properties of some hydrazone derivatives

Dielectric and mechanical properties of nickel silica core-shell reinforced PMMA nanocomposites

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