“…For all samples, the color coordinates ( x , y ) are located in the red region. Referring to the National Television System Committee [NTSC; illuminant red = (0.67, 0.33)], the 5%-doped gallium melilite (Ca 1.85 Eu 0.1 Ga 2 SiO 7 ) exhibits well comparable pure red CIE color coordinates (0.639, 0.358), which are due to the huge emission intensity of the 5 D 0 → 7 F 2,4 transition.…”
Novel melilite-type Ca2Ga2SiO7:Eu(3+) red-emitting phosphors with different Eu(3+) contents were synthesized via high-temperature solid-state reaction. The crystal structure, optical absorption, and photoluminescence properties were investigated, while density functional theory calculations were performed on the host lattice. The excitation spectra indicate that phosphors can be effectively excited by near-UV light for a potential application in white-light-emitting diodes. Because of the abnormally high intensity emission at about 700 nm arising from the (5)D0 → (7)F4 transition of Eu(3+), the phosphors Ca2Ga2SiO7:Eu(3+) show a deep-red emission with chromaticity coordinates (0.639, 0.358).
“…For all samples, the color coordinates ( x , y ) are located in the red region. Referring to the National Television System Committee [NTSC; illuminant red = (0.67, 0.33)], the 5%-doped gallium melilite (Ca 1.85 Eu 0.1 Ga 2 SiO 7 ) exhibits well comparable pure red CIE color coordinates (0.639, 0.358), which are due to the huge emission intensity of the 5 D 0 → 7 F 2,4 transition.…”
Novel melilite-type Ca2Ga2SiO7:Eu(3+) red-emitting phosphors with different Eu(3+) contents were synthesized via high-temperature solid-state reaction. The crystal structure, optical absorption, and photoluminescence properties were investigated, while density functional theory calculations were performed on the host lattice. The excitation spectra indicate that phosphors can be effectively excited by near-UV light for a potential application in white-light-emitting diodes. Because of the abnormally high intensity emission at about 700 nm arising from the (5)D0 → (7)F4 transition of Eu(3+), the phosphors Ca2Ga2SiO7:Eu(3+) show a deep-red emission with chromaticity coordinates (0.639, 0.358).
“…Compounds 1a – d were characterized using elemental analysis as well as spectroscopic data. Compounds 1a , b were prepared according to literature procedures [33, 40]. Scheme 1Synthesis of pyrimidine-5-carbonitriles 1a – d
…”
Section: Resultsmentioning
confidence: 99%
“…The probabilities of compounds towards excitation from the ground state to the singlet excited state (absorption cross-section σ a ) by absorbing photons at wavelength of 326 nm were calculated using Eq. (1) as follows [40]: σ a = 0.385 × 10 −20 ε where: the molar absorptivity ε was calculated from Beer–Lambert law Eq. (2):where: A: absorbance, I 0 and I: intensities of incident and emerged light from the sample, C: molar concentration of compounds and L is the light path (1 cm).…”
Background and objectiveA series of thiazolopyrimidine derivatives have been synthesized via multicomponent reaction and tested for biological activities. This research aims to develop a new synthetic method of poly fused pyrimidines under microwave irradiation. 6-Amino-4-aryl-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carbonitriles reacted with bromomalono-nitrile to give 3,7-diamino-5-aryl-5H-thiazolo[3,2-a]pyrimidine-2,6-dicarbonitrile more willingly than the isomeric 7H-thiazolo[3,2-a]pyrimidines. Thiazolopyrimidine derivatives reacted with carbon disulphide to produce 11-aryl-11H-1,2,3,4,7,8,9,10-octahydropyrimido[4″,5″:4′,5′]thiazolo[3′,2′-a]pyrimido[4,5-d]pyrimidine-2,4,8,10-tetrathione. The above mentioned reactions were established by using both conventional methods and microwave-assisted irradiation.ConclusionThis work provides a new method for preparing poly fused pyrimidines. The microwave-assisted technique is preferable due to the yield enhancements attained, time saving, and environmental safety reactions. The newly prepared compounds were verified for their antimicrobial activities. Also, the absorption and emission of some of the prepared compounds were studied.
“…The pyrovanadates M 2 V 2 O 7 , where M = Ca, Sr, Pb, Ba, Mg, Zn, Co, Ni, Cu, Mn, Cd, demonstrate promising magnetic (Bhatia et al ., 2010; Basiev et al ., 2011; Sanchez-Andujar et al ., 2011), optical (Cid-García et al ., 2012; Dalal et al ., 2015; Takahashi et al , 2016), and electrical (Cowin et al ., 2011) properties. The physico-chemical properties and structures of divalent metal vanadates have been studied in depth.…”
Polycrystalline samples of Ca2Zn2(V4O14) (I) and Pb2Cd2(V3O10)(VO4) (II) were synthesized using the nitrate–citrate method (I) and conventional solid state reaction (II). The structural refinement based on X-ray powder diffraction data showed that the crystal structure of (I) is characterized by monoclinic symmetry with unit-cell parameters a = 6.8044(1) Å, b = 14.4876(3) Å, c = 11.2367(2) Å, β = 99.647(1)° [space group P21/c (No. 14), Z = 4], and the crystal structure of (II) is triclinic with unit-cell parameters a = 7.03813(6) Å, b = 12.9085(1) Å, c = 6.99961(5) Å, α = 90.7265(5)°, β = 96.3789(5)°, γ = 94.9530(6)°, V = 629.470(8) Å3 [space group P$\bar 1$ (No. 2), Z = 2].
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