bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Axial-Ligand Replacement of the [Tetrakis(1-methyl-4-pyridinio)porphine]iron(III) Ion by the Cyanide Ion in a Highly Alkaline Aqueous Solution
Authors: Arifuku Fumihiro , Ujimoto Kikujiro , Kurihara Hirondo 
Published: July 2006

Abstract
The axial-ligand replacement of the [Tetrakis(1-methyl-4-pyridinio)porphine]iron(III) ion by the cyanide ion was investigated in a highly alkaline aqueous solution by means of the spectrophotometric method at 25 °C. In the course of the replacement, a protolytic equilibrium between monocyanomonoaqua- and monocyanomonohydroxo complex ions was observed; the p(Ka/mol dm−3 value of the monocyanomonoaqua complex ion was found to be 12.2±1.1. In the formation of the dicyano complex ion, the rate-determining step was the second replacement of axial ligands, i.e., from the monocyano complex ion to the dicyanocomplex ion; according as the pH is 11 or 13, the equilibrium constant was found to be 38.0 mol−1 dm3 or 11.0, while the rate constant was 1.07×10−3 or 4.23×10−3 mol−3 dm3 s−1.
Preparations and Thermal Isomerization of Some Tricarbonyl(1-silacyclohexadiene) Iron Complexes. Silyl and Hydrogen Migration in the Diene and the Diene Complex
Authors: Nakadaira Yasuhiro , Kobayashi Toshiaki , Sakurai Hideki 
Published: July 2006

Abstract
The reaction of 1,1-dimethyl-2,5-diphenyl-1-silacyclohexa-2,4-diene with iron pentacarbonyl or diironnonacarbonyl gave a mixture of tricarbonyl(1,1-dimethyl-2,5-diphenyl-1-silacyclohexa-2,4-diene)iron and tricarbonyl(1,1-dimethyl-3,6-diphenyl-1-silacyclohexa-2,4-diene)iron. Similarly, on treatment with iron pentacarbonyl 1,1-dimethyl-2,5-diphenyl-4-trimethylsilyl-1-silacyclohexa-2,5-diene yielded a mixture of tricarbonyl-(1,1-dimethyl-3,6-diphenyl-4-trimethylsilyl-1-silacyclohexa-2,4-diene)iron, tricarbonyl(1,1-dimethyl-2,5-diphenyl-4-trimethylsilyl-1-silacyclohexa-2,4-diene)iron, and tricarbonyl(1,1-dimethyl-2,5-diphenyl-6-trimethylsilyl-1-silacyclohexa-2,4-diene)iron as a result of migration of the hydrogen on the ligand competing with silyl migration. On thermolysis, 1,1-dimethyl-2,5-diphenyl-4-trimethylsilyl-1-silacyclohexa-2,5-diene underwent only 1,3-silyl-migration to yield 1,1-dimethyl-2,5-diphenyl-6-trimethylsilyl-1-silacyclohexa-2,4-diene. The mechanism of transition-metal assisted hydrogen-migration is discussed.
The Effect of Triple-Ion Formation on the Electron-Exchange Reaction Rate between Quinone and Semiquinone Anion Radical
Authors: Takiguchi Tsuyoshi , Suga Kosaku , Aoyagui Shigeru 
Published: July 2006

Abstract
The rate constant and activation parameters of electron-exchange reactions between duroquinone, p-benzoquinone and 2,5-di-t-butyl-p-benzoquinone and their respective semiquinone anions which form ion-pairs or triple-ions with Na+ and K+ were determined. The rate constants of triple-ions were smaller than those of corresponding ion-pairs; the rate constants of potassium ion pairs and triple-ions were larger than those of the corresponding sodium aggregates; and the rate constants of triple-ions decreased upon increasing the size of the substituent for quinone. These results were explained on the basis of a mechanism which is generally accepted for electron-exchange reactions of ion pairs of anion radicals.
Adsorption of Cationic Surfactants on Phospholipid Membranes and Its Contributions to Membrane-Surface Potential
Authors: Matsumura Hideo , Iwamoto Miyako , Furusawa Kunio 
Published: July 2006

Abstract
The adsorption behavior of cationic surfactants (alkyltrimethylammonium ions) on the phospholipid (phosphatidylethanolamine) membranes has been studied by means of interfacial electrostatic measurements, i.e., the surface potential of the monolayer and the zeta potential of the vesicles, in order to elucidate the balance between hydrophobic and electrostatic interactions. The data have been analyzed in terms of the interfacial electrochemical concept; these analyses have revealed that the hydrophobic interaction of a surfactant with the phospholipid membrane is the main motive force for adsorption and there is a critical alkyl-chain length to promote the surfactant adsorption. Furthermore, it was found that the electrostatic interactions between the surfactant and the phospholipid membrane, and among the surfactants themselves, also play a role in their adsorption.
Studies in the Extraction of Cadmium with Some Sulfur Ligands
Authors: Lahiri Roma , Rao G N 
Published: July 2006

Abstract
Extraction of cadmium(II) with 2-(2-pyridyl)-2,3-dihydrobenzothiazole, O,O′-diethyl hydrogenphosphorodithioate, 1-phenyl-3-methyl-4-thiobenzoyl-5-pyrazolone, N-(2-naphthyl)mercaptoacetamide, and 2-(o-hydroxyphenyl)-2,3-dihydrobenzothiazole has been studied. Extraction constants (Kex) have been calculated for these systems. These reagents have been compared with some common reagents used for the extraction of cadmium. Separation factors have been calculated for the separation of cadmium from zinc with some of these reagents.
Reaction of 2-Aminobenzohydrazides with Schiff Bases. A New Route to 3-Benzylideneamino-4(3H)-quinazolinones and 2-[2-(Methylamino)phenyl]-5-aryl-1,3,4-oxadiazoles
Authors: Reddy Padi Pratap , Reddy Cheppala Kista , Reddy Padala Satyanarayana N 
Published: July 2006

Abstract
Reaction of 2-aminobenzohydrazides with Schiff bases in methanol followed by KMnO4 oxidation has resulted in the respective formation of 3-benzylideneamino-4(3H)-quinazolinones and 2-[2-(methylamino)phenyl]-5-aryl-1,3,4-oxadiazoles, characterized by spectral and analytical methods.
Synthesis of New Arginine Derivatives as Substrates of Trypsin
Authors: Somorin Oyin , Ameghashitsi Leo 
Published: July 2006

Abstract
Eight new chromogenic arginine substrates: Nα-benzyloxy-carbonyl-l-arginine 3,5-dinitroanilide hydrochloride (l-ZADA·HCl), Nα-benzyloxycarbonyl-l-arginine 3-nitroanilide hydrochloride (l-ZANA·HCl), Nα-benzyloxycarbonyl-l-arginine 3-nitro-5-chloroanilide hydrochloride (l-ZANCA·HCl), Nα-benzyloxycarbonyl-l-arginine 3-nitro-5-bromoanilide hydrochloride (l-ZANBA·HCl), Nα-benzyloxycarbonyl-l-arginine 3-nitro-5-fluoroanilide hydrochloride (l-ZANFA·HCl), Nα-benzyloxycarbonyl-l-arginine 3-nitro-5-iodoanilide hydrochloride (l-ZANIA·HCl), Nα-benzyloxycarbonyl-l-arginine 3-nitro-5-(methylsulfonyl)anilide hydrochloride (l-ZANMA·HCl), and Nα-benzyloxycarbonyl-l-arginine 3-nitro-5-(trifluoromethyl)anilide hydrochloride (l-ZANTA·HCl) were synthesized by coupling 5-substituted 3-nitroanilines with Nα-benzyloxycarbonyl-l-arginine hydrochloride. These substrates were found to be susceptible to trypsin-catalyzed hydrolysis. These series of substrates are suitable for studying electronic effects on trypsin activity.
The Positional Dependence of Anodic Peak Potentials in N-Substituted Adenines
Authors: Sato Takeo , Fukuzaki Kentaro , Fujii Tozo 
Published: July 2006

Abstract
In order to determine the structural dependence on the anodic potential, cyclic voltammetric measurements were carried out for 1-, 3-, 7-, 9-, and N6-alkyladenines in N,N-dimethylformamide (DMF) or in acetonitrile (AN). The anodic peak potential, Epa, in DMF was found to be sensitive to the substitution and shifted anodic in the order, 7-&lt;1-&lt;3-, N6-&lt;9-substituted derivatives. These data, with the aid of solvent effects, are useful for determining the substitution pattern in N-alkyladenines.
Molecular Rearrangements. XXIV. Thermolysis of Phenylhydrazones
Authors: Mahgoub Safaa Abd El-Salam , Fahmy Atiat Mohammed , Aly Morsy Mohammed , Badr Mahmoud Zaif Amin 
Published: July 2006

Abstract
Thermolysis of acetophenone phenylhydrazone by reflux in air for 24 h gives ammonia, benzonitrile, acetophenone, biphenyl, aniline, o- and p-toluidines, together with 7-methyl-3-phenylindole, while that of benzophenone phenylhydrazone gives ammonia, benzophenone, N-benzhydrylideneaniline, biphenyl, aniline, benzonitrile, and 9-phenylacridine.
Induced Cholesteric Mesophases as a Probe for the Stereochemistry of Chiral Biphenyls
Authors: Gottarelli Giovanni , Spada Gian Piero , Seno Kaoru , Hagishita Sanji , Kuriyama Kaoru 
Published: July 2006

Abstract
In the studies of the induced cholesteric mesophases, the twisting powers of cisoid- and transoidbridged 2,2′-diaminobiphenyl derivatives having R-configuration were found to be negative and positive respectively. In the cases where CD spectroscopy is inadequate, the liquid crystal method is sensitive to the helicity of the biphenyl moiety. The conformation of 2,2′-diamino-6,6′-dimethylbiphenyl is discussed.
Kinetics of Axial Substitution of the Iron(II) Complex of 2,3,9,10-Tetraphenyl-1,4,8,11-tetraaza-1,3,8,10-cyclotetradecatetraene in Acetonitrile. Evidence for a Dissociative-Interchange Mechanism
Authors: Funahashi Shigenobu , Uchiyama Naotaka , Tanaka Motoharu 
Published: July 2006

Abstract
The reaction of the iron(II) complex of 2,3,9,10-tetraphenyl-1,4,8,11-tetraaza-1,3,8,10-cyclotetradecatetraene ([FeL(CH3CN)2]2+, 1) with imidazole and thiocyanate ion in acetonitrile has been investigated spectrophotometrically at various temperatures and pressures. The axial substitution of 1 with imidazole is first order with respect to the concentration of the iron(II) complex and imidazole and the rate constant and the activation parameters are obtained as k (25.0 °C)=0.69 mol−1 kg s−1, ΔH\eweq=76±4 kJ mol−1, ΔS\eweq=7±13 J mol−1 K−1, ΔV\eweq=13.7±0.9 cm3 mol−1. It has been demonstrated that at higher concentration of imidazole there exists self-associated imidazole which does not react directly with the complex. The axial substitution of 1 with thiocyanate ion proceeds through the ion-association between 1 and SCN− prior to the rate-determining step from the outer-sphere complex to the inner-sphere complex. The activation parameters for the rate-determining step were determined as follows: k0 (25.0 °C and 0.1 MPa)=2.35 s−1, ΔH\eweq=86±2 kJ mol−1, ΔS\eweq=51±6 J mol−1 K−1, ΔV\eweq=10.1±0.2 cm3 mol−1. The positive activation volumes strongly indicate a dissociative character of the activation process.
The Microwave Spectrum of Methyl Isoselenocyanate
Authors: Sakaizumi Takeshi , Yasukawa Atsushi , Miyamoto Hirobumi , Ohashi Osamu , Yamaguchi Ichiro 
Published: July 2006

Abstract
The microwave rotational spectra of two isotopic species of methyl isoselenocyanate(CH3NCSe with 80Se and 78Se) in the ground vibrational state(A-species) have been assigned in the 9 to 40 GHz frequency range and the rotational and centrifugal distortion constants for the ground vibrational state have been determined. Three r0 structural parameters have been determined from the observed rotational constants of the two species.
Spectrophotometric Determination of Scandium(III) with o-Hydroxyhydroquinonephthalein in Cationic Micellar Media
Authors: Mori Itsuo , Fujita Yoshikazu , Fujita Kinuko , Usami Atsuko , Kawabe Hiroshi , Koshiyama Yozo , Tanaka Takeshi 
Published: July 2006

Abstract
A spectrophotometric method for determining trace amounts of scandium(III) has been established which makes use of formation of its ternary complex with o-hydroxyhydroquinonephthalein (Qnph) and N-hexadecyl-pyridinium chloride (HPC) as a cationic surfactant at pH 5.4. The molar ratio of the ternary complex among Qnph, scandium(III), and HPC is 3:2:6 in a weakly acidic medium, and its maximum absorbance is at 555 nm against a reagent blank. Beer’s law holds in the concentration range 0–4.5 μg of scandium(III) in a final volume of 10 cm3 at 555 nm. The apparent molar absorptivity is 1.0×105 dm3 mol−1 cm−1 with a Sandell sensitivity of 0.0005 μg cm−2. The coefficient of variation was 0.6% (n=5) for 2.7 μg of scandium(III).
Selective Photooxidation of Alkali Mandelates by a Flavin Bearing a Crown Ring as a Metal Recognition Site
Authors: Shinkai Seiji , Nakao Hideki , Ueda Kaori , Manabe Osamu , Ohnishi Masayoshi 
Published: July 2006

Abstract
The quantum yields (Φ) for photooxidation of mandelate salts by a crown-containing flavin (CrFl) and 3-methyl-10-ethylisoalloxazine (MeEtIA) were determined in acetonitrile. MeEtIA photooxidized tetramethylammonium mandelate more selectively than potassium mandelate (ΦK+⁄ΦMe4N+=0.42–0.64), while CrFl showed a high selectively for photooxidation of potassium mandelate (ΦK+⁄ΦMe4N+=19–42).
Induced Circular Dichroism in the Complexes of Sequential Lysine Polypeptides with Methyl Orange. On Intermolecular Aggregation of the Complexes and Distance between Lysine Residues
Authors: Yamamoto Hiroyuki , Nishida Ayako , Hayakawa Tadao , Nishi Norio , Yamamoto Ryo 
Published: July 2006

Abstract
Aggregation of the sequential poly(Lys HCl-X) (X: Gly, βAla, and εAhx)–Methyl Orange (MO) complexes was studied by means of a circular dichroism (CD) measurement. The intensity of the induced CD was affected by the concentration of the complexes and time after preparing the complex solutions. When MO molecules which are electrostatically bound to lysine residues are separated from each other, the aggregation of the complexes takes place to a lesser degree.
Aryliminodimagnesium Reagents. X. The Mild Reagent Derived from 2-Aminopyridine and Formation of Highly Reactive Azoxypyridines in the Reaction with Nitrobenzenes
Authors: Okubo Masao , Sugimori Chieko , Tokisada Mitsunao , Tsutsumi Toshiki 
Published: July 2006

Abstract
The reaction of iminodimagnesium reagent derived from 2-amino-4-methylpyridine with nitrobenzenes was examined. The relative yields of the azoxypyridine formed via condensation and the azopyridines via deoxygenation and oxidative dimerization were explained in terms of weak electron-donating ability of the reagent and the strong electron-accepting ability of the azoxypyridine.
The H-1 NMR Solvent Shifts and Reactivity Parameters of Several Aromatic Compounds
Authors: Tamaoki Akihiro , Takahashi Kensuke 
Published: July 2006

Abstract
H-1 NMR solvent shifts were measured for 7 aromatic hydrocarbons and 13 heteroaromatic compounds. The chemical shifts can be correlated to the selfpolarizabilities of the carbon atoms attached to the hydrogens in the aromatic hydrocarbons and will be of use in predicting the reactivities of the compounds. However, in the case of heteroaromatic compounds, no good correlation has been found between the reactivity parameters and the H-1 NMR solvent shifts.
Dehydrogenation of Ethylbenzene on Potassium-Promoted Iron Oxide Catalysts Containing Various Transition Metal Oxides
Authors: Hirano Takenori 
Published: July 2006

Abstract
Various transition metal oxides, i.e., CeO2, Cr2O3, ZrO2, V2O5, WO3, and MoO3, were added to a potassium-promoted iron oxide catalyst to study their effects on the dehydrogenation activity of the catalyst. CeO2 was found to promote styrene formation most strongly among the oxides examined, by lowering the activation energy.
Thermically-Initiated Fluorinations at Saturated Carbon Atoms with Xenon Difluoride
Authors: Zajc Barbara , Zupan Marko 
Published: July 2006

Abstract
The heating of several hydrocarbons with xenon difluoride at 95–120 °C in stainless steel reactors equipped with teflon jackets resulted in mono-, di-, and trisubstituted products.
Rapid Spectrophotometric Determination of Scandium(III) with (Pyridylazo)- and (Thiazolylazo)naphthols
Authors: Sharma Chander Dhar , Nagarkar Sujansingh G , Eshwar Muppalla C 
Published: July 2006

Abstract
Scandium(III) reacts with 1-(2-pyridylazo)-2-naphthol [PAN] and 1-(2-thiazolylazo)-2-naphthol [TAN] in weakly acidic media to yield red colored 1:1 and 1:2 chelates, respectively. These complexes are sparingly soluble in water but readily soluble in ≥24% (v/v) acetone and ≥32% (v/v) methanol, giving maximum absorbances at 545 and 570 nm for the PAN and TAN complexes, respectively. Beer’s law is obeyed over the concentration ranges of 0.16 to 1.40 μg and 0.08 to 1.40 μg of Sc(III) per ml with PAN and TAN. The scandium(III) complexes formed with PAN and TAN have the molar absorptivities of 1.90×104 and 2.93×104 dm3 mol−1 cm−1 at their absorption maxima, respectively. The effect of diverse ions on the determination of scandium with these reagents is also investigated.
Phase-Shift Studies of the Quenching of NH(c1Π) and NH(A3Π) by Hydrocarbons
Authors: Sasaki Shun-ichiro , Kano Akiko , Tsunashima Shigeru , Sato Shin 
Published: July 2006

Abstract
The cross-sections for quenching NH(c1Π) and NH(A3Π) by hydrocarbons were determined at room temperature by using a phase-shift method. The NH(c1Π) was produced by the photolysis of HN3 using an amplitude-modulated Xe-resonance lamp. The apparent decay rate of the NH(c1Π) was estimated from the difference in phase angle between the excitation light and the fluorescence of NH(c1Π) at 325 nm. In the presence of Xe, the fluorescence of NH(A3Π) at 336 nm was enhanced. The difference in the phase angle between the fluorescences at 325 and 336 nm was found to correlate with the decay rate of NH(A3Π). From the decay rates obtained in the presence of hydrocarbons, the quenching cross-sections were determined.
Preparation and Characterization of [RhCl2(edpp)2]+ (edpp=(2-aminoethyl)diphenylphosphine). Crystal Structures of trans(Cl,Cl), cis(P,P)-[RhCl2(edpp)2]Cl·2C2H5OH and cis(Cl,Cl), trans(P,P)-[RhCl2(edpp)2]Cl·4H2O
Authors: Galsbøl Frode , Kojima Masaaki , Ishii Toshio , Ohba Shigeru , Saito Yoshihiko , Fujita Junnosuke 
Published: July 2006

Abstract
Two of the five possible geometrical isomers of [RhCl2(edpp)2]+ were formed by reaction of RhCl3·2H2O with edpp (edpp=(2-aminoethyl)diphenylphosphine) in 1:2 molar ratio in ethanol. The chlorides of the isomers were separated by fractional crystallization from ethanol. The structures of the more soluble (main product) and the less soluble (minor product) complexes were determined by X-ray analyses to have the trans(Cl,Cl), cis(P,P) and cis(Cl,Cl), trans(P,P) configurations, respectively. Crystal data are: for trans(Cl,Cl), cis(P,P)-[RhCl2(edpp)2]Cl·2C2H5OH, triclinic, space group P\bar1, with a=10.024(3), b=18.865(3), c=9.833(2) Å, α=97.66(1), β=103.92(2), γ=82.30(2)°, and Z=2, and for cis(Cl,Cl), trans(P,P)-[RhCl2(edpp)2]Cl·4H2O, triclinic, space group P\bar1, with a=11.341(4), b=17.780(6), c=8.712(3) Å, α=95.60(4), β=112.31(3), γ=82.56(4)°, and Z=2. The trans influence of the P atom on the Rh–N and Rh–P bond lengths is observed. The mean Rh–N and Rh–P bond lengths (2.125(4) and 2.300(1)Å) in the trans(Cl,Cl), cis(P,P) isomer are respectively longer and shorter than those of the cis(Cl,Cl), trans(P,P) isomer (2.078(12) and 2.336(3)Å). 13C NMR and absorption spectra of the isomers were recorded and are discussed.
AlCl3-Promoted Conjugate Reduction of α,β Unsaturated Carbonyl Compounds with 1,3-Dimethyl-2-phenylbenzimidazoline
Authors: Chikashita Hidenori , Itoh Kazuyoshi 
Published: July 2006

Abstract
The reduction of a variety of α,β-unsaturated carbonyl compounds, except for α,β-unsaturated aldehyde, to the corresponding saturated carbonyl compounds was effectively performed by using 1,3-dimethyl-2-phenylbenzimidazoline (DMBI) as a reducing agent with the aid of AlCl3. The reduction is discussed on the basis of the hydride-donating ability of DMBI, together with the role of AlCl3 as an electrophilic activator for the substrates. The catalytic efficiency of Lewis acids was found to be proportional to the efficiency to form a complex with a carbonyl group. The reduction of 2-cinnamoylpyridine with 2-deuterated DMBI revealed that in the reduction product, a deuterium atom was located at the β-position with respect to the carbonyl group. On the other hand, the reduction of the same substrate with DMBI followed by quenching with D2O gave a reduced product which contained a deuterium label at the α-position. These results were interpreted in terms of a mechanism involving an enolate intermediate produced by either a one-step hydride transfer or a sequential transfer of an electron (e) and a hydrogen atom (H·) from the reducing agent to the substrate.
Homogeneous Asymmetric Hydrogenation Using a Chiral Phosphinite Derivative of Carbohydrates as Ligand
Authors: Yamashita Mitsuji , Kobayashi Mineaki , Sugiura Motoyuki , Tsunekawa Kenji , Oshikawa Tatsuo , Inokawa Saburo , Yamamoto Hiroshi 
Published: July 2006

Abstract
Diphenylphosphinite derivatives of sugars were conveniently synthesized by the reaction of diphenylphosphinous chloride–triethylamine with sugar derivatives. Homogeneous asymmetric hydrogenations of several prochiral olefins, i.e., (Z)-α-acetylaminocinnamic acid, (Z)-α-benzoylaminocinnamic acid, itaconic acid, tiglic acid, and their esters, were carried out using rhodium(I) catalysts with the tervalent chiral phosphorus derivative of sugars. The highest optical yields for all the prochiral substrates investigated were obtained when di-μ-chloro-bis(cyclooctadiene)dirhodium(I) and methyl 2,3-O-isopropylidene-4-O-(diphenylphosphino)-α-l-rhamnopyranoside were used.
Synthesis of Oligodeoxyribonucleotides Involving a Rapid Procedure for Removal of Base-Protecting Groups by Use of the 4,4′,4″-Tris(benzoyloxy)trityl (TBTr) Group
Authors: Sekine Mitsuo , Masuda Narihiro , Hata Tsujiaki 
Published: July 2006

Abstract
Fully protected building units for oligodeoxyribonucleotide synthesis in the phosphoramidite approach were prepared in high yields by the 5′-dimethoxytritylation of N-[4,4′,4″-tris(benzoyloxy)trityl]deoxyribonucleosides followed by the 3′-phosphitylation with methoxymorpholinochlorophosphine. The solid phase synthesis of oligodeoxyribonucleotides on a controlled pore glass gel using the amidite units was examined. The efficiency of condensation was discussed in detail. The 4,4′,4″-tris(benzoyloxy)trityl (TBTr) group was removed rapidly from a protected tetramer synthesized on the controlled pore glass gel to give dGpCpApT.
Ni(II)-Bearing Green Rust II and Its Spontaneous Transformation into Ni(II)-Bearing Ferrites
Authors: Tamaura Yutaka 
Published: July 2006

Abstract
When solutions containing Fe(II), Ni(II), and SO42− ions were oxidized by a mixed gas of air and nitrogen at pH 7.1 (25 °C), a Ni(II)-bearing green rust II (GR-II), which is a uniform crystalline precipitate with a definite chemical composition, was formed. The Ni(II) content in the Ni(II)-bearing GR-II increased with an increase in the Ni(II) concentration in the reaction solution. The Ni(II)-bearing GR-II was spontaneously transformed into Ni(II)-bearing ferrite under a nitrogen atmosphere without any oxidant. The metal mole ratio of [Ni(II)/ Fe(III)]fer in the ferrite increased linearly with an increase in that of [Ni(II)/Fe(III)]grn in the Ni(II)-bearing GR-II (slope=0.193). From this relationship, the spontaneous transformation reaction was described as
2(Ni2+)x(Fe2+)2−x(Fe3+)(SO42−)(OH−)5→Ni0.39xFe3−0.39xO4+(2−1.61x)Fe2++1.61xNi2++Fe(OH)2+2SO42−+4H2O.
This equation shows that Fe(II) ion in the GR-II is more readily incorporated into the ferrites than Ni(II) ion.
Analytical Use of Luminescence Induced Ultrasonically in Solution. I. Sonic Chemiluminescence of Luminol for Determination of Cobalt(II) at Sub-pg Levels by Flow Injection and Continuous Flow Methods
Authors: Komatsu Takayuki , Ohira Minoru , Yamada Masaaki , Suzuki Shigetaka 
Published: July 2006

Abstract
Ultrasonic irradiation of alkaline luminol solution produces intense light emission (sonic chemiluminescence) as a result of the reaction of luminol with reactive species which are generated ultrasonically from water molecule. For the analytical application of ultrasound-induced luminescence, the sonic chemiluminescence of luminol is first utilized for the determination of ultratraces of cobalt(II) by flow injection and continuous flow methods. This novel method is based on the measurement of sonic chemiluminescence enhanced by the presence of cobalt(II); it provides analytical characteristics comparable to those for the conventional luminol chemiluminescence method using hydrogen peroxide as an oxidizing agent. The limit of detection is 0.06 pg(10-μl sample injection) or 0.06 pg ml−1 (continuous sample flow), the linear dynamic range is 3 orders of magnitude (10-μl sample injection), the sampling rate is 120 h−1, and the relative standard deviation is 3.9% for 6 pg Co(II) (n=10). The method is successfully applied to real samples. Possible explanation of sonic chemiluminescence is also presented; the mechanism involving superoxide anion radical is proposed for the cobalt(II)-catalyzed sonic chemiluminescence.