Spektralna istraživanja spinelnog feritnog sistema NixZn1−xFe2O4

X-ray diffraction, DTA, IR and SEM investigations were carried out for a series of samples of the system NixZn1-xFe2O4 (with x=0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) prepared using the usual ceramic technique. The analysis of X-ray diffraction indicates that the samples have single phase with spinel cubic structure. The lattice constant (a), radius of tetrahedral ions (rtet), bulk density (D) and theoretical density (Dx) were found to decrease while the porosity (P) increases as the content of nickel ions (x) increases. SEM images indicate observable variations between the different compositions. IR absorption spectra showed the four characteristic peaks of ferrites. The position and intensity of the peaks are markedly composition dependent.Na nizu uzoraka sistema NixZn1−xFe2O4 (za x = 0,0, 0,2 , 0,4 , 0,6 , 0,8 i 1,0) pripremljenih uobičajenom keramičkom tehnikom, izvršena su mjerenja difrakcijom rendgenskog zračenja, diferencijalna termička analiza, optička mjerenja u infracrvenom području i snimanja skanirajućim elektronskim mikroskopom. Analiza difrakcije rendgenskog zračenja indicira da uzorci imaju jednu fazu sa spinelnom kubičnom strukturom. Nadeno je da konstanta rešetke, promjeri tetrahedralnih iona, volumna i teoretska gustoća padaju a poroznost raste s porastom sadržaja nikla. Slike dobivene skanirajućim elektronskim mikroskopom indiciraju primjetne promjene među različitim smjesama. Spektri infracrvene apsorpcije pokazuju četiri karakteristična vrha za ferite. Položaj i intenzitet vrhova značajno ovise o sastavu sistema

Spektralna istraživanja spinelnog feritnog sistema NixZn1−xFe2O4

X-ray diffraction, DTA, IR and SEM investigations were carried out for a series of samples of the system NixZn1-xFe2O4 (with x=0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) prepared using the usual ceramic technique. The analysis of X-ray diffraction indicates that the samples have single phase with spinel cubic structure. The lattice constant (a), radius of tetrahedral ions (rtet), bulk density (D) and theoretical density (Dx) were found to decrease while the porosity (P) increases as the content of nickel ions (x) increases. SEM images indicate observable variations between the different compositions. IR absorption spectra showed the four characteristic peaks of ferrites. The position and intensity of the peaks are markedly composition dependent.Na nizu uzoraka sistema NixZn1−xFe2O4 (za x = 0,0, 0,2 , 0,4 , 0,6 , 0,8 i 1,0) pripremljenih uobičajenom keramičkom tehnikom, izvršena su mjerenja difrakcijom rendgenskog zračenja, diferencijalna termička analiza, optička mjerenja u infracrvenom području i snimanja skanirajućim elektronskim mikroskopom. Analiza difrakcije rendgenskog zračenja indicira da uzorci imaju jednu fazu sa spinelnom kubičnom strukturom. Nadeno je da konstanta rešetke, promjeri tetrahedralnih iona, volumna i teoretska gustoća padaju a poroznost raste s porastom sadržaja nikla. Slike dobivene skanirajućim elektronskim mikroskopom indiciraju primjetne promjene među različitim smjesama. Spektri infracrvene apsorpcije pokazuju četiri karakteristična vrha za ferite. Položaj i intenzitet vrhova značajno ovise o sastavu sistema

Električna i termoelektrična svojstva čistog i supstituiranih bakrenih ferita

Samples of the CuFe2-xAlxO4 system with x=0, 0.2, 0.4 and 0.6 were prepared. The single phase spinel structure was verified by X-ray diffraction method. The thermoelectric power (a) and dc electrical resistivity (r) were studied as a function of temperature and composition. The results show that the resistivity increases and the transition temperature decreases with increasing the aluminium substitution. The activation energy in ferrimagnetic region is lower than that in paramagnetic region. The drift mobility of carriers increases exponentially with temperature as expected for ferrites.Priređeni su uzorci sistema CuFe2−xAlxO4 sa x = 0, 0,2, 0,4 i 0,6. Proučavana je termoelektrična sila i dc električna otpornost u ovisnosti o temperaturi i sastavu. Rezultati mjerenja pokazuju da se otpornost povećava a temperatura prijelaza smanjuje sa povećanjem koncentracije aluminija. Aktivacijska energija veća je u feromagnetskoj nego u paramagnetskoj fazi. U skladu s očekivanjem, ustanovljeno je da se mobilnost nosilaca naboja u feritima eksponencijalno povećava s temperaturom

Regioselective lithiation of chiral 3-acylamino-2-alkylquinazolin-4(3H)ones: application in synthesis

Reaction of 3-amino-2-alkylquinazolin-4(3H)-ones with several chiral acid chlorides was found to be dependent on the molar proportions. When a 1:1 molar mixture was heated under reflux, the corresponding 3-(diacylamino)- derivatives were obtained in poor yields. However, when a 2:1 molar mixture was reacted in refluxing toluene, the 3-acylamino- derivatives were obtained in good yields based on the acid chloride. Lithiation of the 3-acylamino-2-alkyl­quinazolin-4(3H)-ones was achieved by the use of lithium diisopropylamide (LDA) in anhydrous THF at -78 °C and the reaction was regioselective at the carbon α to position 2 of the quinazolin-4(3H)-one moiety. The dilithio reagents thus obtained reacted with electrophiles to give the corresponding 2-substituted derivatives in very good yields. The NMR spectra of the products show the expected diastereotopism for all the CH2 groups and provide evidence for long-range asymmetric induction

Crystal structure of ethyl 4-amino-5-(5-methyl-1-(4-tolyl)-1H-1,2,3-triazole-4-carbonyl)-2-(phenylamino)thiophene-3-carboxylate, C24H23N5O3S

C24H23N5O3S, triclinic, P1̅ (no. 2), a = 9.1704(9) Å, b = 10.1253(11) Å, c = 12.2182(14) Å, α = 83.686(10)°, β = 89.542(9)°, γ = 76.982(9)°, V = 1098.5(2) Å3, Z = 2, Rgt(F) = 0.0551, wRref(F2) = 0.1510, T = 296(2) K

Facile, mild and efficient synthesis of azines using phosphonic dihydrazide

Several bis(N'-arylpropanehydrazonoyl chlorides) were synthesized in good yields from condensation reactions of hydrazonoyl chlorides and phosphonic dihydrazide. Under the conditions employed, none of the expected phosphorylhydrazines were isolated. Nucleophilic substitution of bis(N'-arylpropanehydrazonoyl chlorides) with thiophenol, sodium phenylsulfinate, hydroxyl amine, and piperidine afforded the corresponding azines. Similarly, 1,2-bis(heteroaryl)ethylidene)hydrazines were produced from reaction of phosphonic dihydrazide and heteroaryl methyl ketones. The structures of the products were confirmed by NMR and IR spectral data along with X-ray crystal structure determination and their purities were confirmed by the elemental analyses

Synthesis of novel heterocycles using 1,2,3‐triazole‐4‐carbohydrazides as precursors

Herein, we report the synthesis of various heterocyclic ring systems containing 1,2,3‐triazole from the reactions of acid hydrazides and commercially available reagents, using efficient and simple procedures. Reactions of certain 1,2,3‐triazole‐4‐carbohydrazides and α‐bromoketones in boiling ethanol afforded the corresponding hydrazones rather than the expected triazines. The hydrazones could also be synthesized in 85‐90% yield via an alternative pathway that involved the reaction of 1,2,3‐triazole‐4‐carbohydrazides and 4‐acetyl‐1,2,3‐triazoles in boiling ethanol containing glacial acetic acid. Reaction of one of the 4‐carbohydrazides with carbon disulfide, followed by the reaction with hydrazine hydrate, gave 4H‐1,2,4‐triazole‐3‐thiol in 73% yield, which further reacted with other α‐bromoketones in boiling ethanol to afford 7H‐[1,2,4]triazolo[3,4‐b][1,3,4]thiadiazines in 82‐84% yields. Additionally, reactions of certain carbohydrazides with ethyl 2‐cyano‐3,3‐bis(methylthio)acrylate gave 1‐aryl‐1H‐1,2,3‐triazole‐4‐carbohydrazides rather than the expected 1H‐pyrazole‐4‐carboxylates

Synthesis of new derivatives of the 1H-1,2,3-triazole ring using 1-aryl-5-phenyl-1H-1,2,3-triazole-4-carbohydrazides as precursors

Condensation of 1-(4-nitrophenyl)-5-phenyl-1H-1,2,3-triazole-4-carbohydrazide and phenyl isothiocyanate in ethanol in the presence of a catalytic quantity of triethylamine under reflux gave 5-(1-(4-nitrophenyl)-5-phenyl-1H-1,2,3-triazol-4-yl)-N-phenyl-1,3,4-oxadiazol-2-amine in 84% yield. 2-(2-(5-Phenyl-1H-1,2,3-triazole-4-carbonyl)hydrazineylidene)-N-propanehydrazonoyl chlorides were synthesized, in 87–90% yields, by the condensation of 1-(4-nitrophenyl)-5-phenyl-1H-1,2,3-triazole-4-carbohydrazide and hydrazonoyl chlorides. In a similar manner, condensation of 1H-1,2,3-triazole-4-carbohydrazides and carbonyl compounds in boiling ethanol under acidic conditions gave the corresponding hydrazones in 88–92% yield. The structures of the new heterocycles were confirmed by nuclear magnetic resonance spectral data and X-ray crystallography