bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies of Collectors. VIII. The Flotation of the Gallium Ion with Oxine-Type Surfactants
Authors: Koide Yoshifumi , Hokonohara Hisashi , Jinnai Kuniaki , Yamada Kimiho 
Published: July 2006

Abstract
Oxine-type surfactants(5-alkanoyl-8-quinolinol, RnOx, n=2, 8, 12, 18) and R12OOX were prepared and used as ion-flotation collectors. Cu2+, Fe3+, Zn2+, and Pb2+ were floated with R12Ox around a neutral pH, and the selective removal of Cu2+ from the mixture of these four metal ions was observed at pH 1.0. The floatability of Ga3+ was also high around the neutral pH, and the selective Ga3+ flotation from an Al3+ (100 ppm)–Ga3+(20 ppm) mixture was observed by using R8Ox in the pH regions of 3–4 and 10–13.3 (0.2 M NaOH soln), while R12Ox did not float the Ga3+ so much at pH 10–13.3. By the addition of a small amount of RnPy to the R12Ox or by the solvent sublation, an effective flotation of Ga3+ was observed in the pH range of 10–13.3. The Ga3+ flotation was superior to the Ga3+ extraction in pH 2–4. However, in a strong alkaline region the floatability was lower than the extractability.
Reaction Mechanism for Selective Synthesis of Gasoline-Range Isoalkanes from Syngas over RuPtHY Zeolites. II. Role of Metals and Acid Sites
Authors: Shul Yong-Gong , Arai Yukari , Tatsumi Takashi , Tominaga Hiro-o 
Published: July 2006

Abstract
Role of metals and acid site in selective synthesis of gasoline-range isoalkanes from syngas catalyzed by zeolite Y supported Ru–Pt alloy has been studied. As a probe molecule 1-alkene was added into syngas over the various combination of catalysts. Alloying Ru with Pt enhanced 1-octene conversion as well as CO conversion. Reaction of 1-octene over metal-free DAHY (dealuminated HY) zeolite produced cracking products with high selectivity for isobutanes; C3+ carbon number distribution was similar to that from CO hydrogenation over DAHY2R2P (Ru and Pt 2 wt%, respectively), suggesting that the selective formation of isoalkanes in gasoline-range from CO–H2 over DAHY2R2P could be essentially due to acid-catalyzed reactions on zeolites. Cracking of 1-octene was affected by the support and increased in the order: NaY2R2P&lt;HY2R2P&lt;DAHY2R2P. Products via disproportionation were predominant for NaY2R2P and HY2R2P and those via simple cracking prevailed in DAHY2R2P. This could account for shift to light side in carbon number distribution from simple CO hydrogenation over DAHY2R2P. From syngas H2/CO ratio=13/2, methane was the main product. However, methane production was virtually unchanged on addition of 1-octene, implying that the presence of CO suppressed the hydrogenolysis of 1-octene on RuPt bimetallic site. Effects of contact time and temperature on selectivity for products were also discussed.
Cross Sections for the Quenching of Hg(6s6p1P1)
Authors: Umemoto Hironobu , Kasakura Akeo , Kikuma Jun , Sato Shin 
Published: July 2006

Abstract
Absolute cross sections for the quenching of Hg(6s6p1P1) by simple molecules were measured by employing a Stern–Volmer type intensity measurement combined with a phase-shift measurement of effective radiative lifetime. The cross sections are approximately gas kinetic, except for rare gas atoms and tetrafluoromethane. The cross sections can be correlated with the C6 long-range force parameter to the power 0.52.
ESR and Mass-Spectrometric Studies of Methanol Combustion. III. The Effect of CS2 and CH3NH2 Additions on the Concentration Profiles of Chemical Species in a Methanol–Air Flame
Authors: Taniguchi Masayuki , Hirasawa Nobuhito , Yoshida Hiroshi 
Published: July 2006

Abstract
The concentration profiles of chemical species (labile and stable) in methanol–air free-burning flames with and without the addition of CS2 and CH3NH2 have been examined by means of the probe-sampling ESR method, combined with mass-spectrometric measurements. In addition to the principal labile intermediates (H, O, and OH) and stable species (CH3OH, O2, H2, CH2O, CO2, and H2O), SO2 and NO have been detected from the flame when it has been doped with CS2 or CH3NH2 respectively. The observed results indicate that the addition of these dopants depresses the concentration of OH and raises the concentration of H2 in the primary reaction zone, where SO2 and NO are efficiently generated. The observed concentration profiles have been discussed in terms of the reaction mechanism of the oxidation of sulfur and nitrogen compounds.
A Localized Molecular Orbital Approach to Bond Moment Theory. II. The Transferability of Bond Moment Derivatives
Authors: Shinoda Hiroyuki 
Published: July 2006

Abstract
The transferability of bond moment derivatives(BMDs) in the bond moment theory was investigated by the use of localized molecular orbitals derived from INDO canonical orbitals. Five series of molecules were treated, two for a terminal C–H stretching motion and three for an O–H one. It is concluded that the transferability of BMDs with significant values is recognized among the molecules which have the same structure within the second neighbor bonds; it is also concluded that the changes in the molecular moiety beyond the third neighbor bonds slightly affect the BMDs of all the bonds, with the exception of the stretching one. These conclusions were confirmed by theoretical considerations, such as perturbation expansion.
The Pyrolysis of Heptathiazocine
Authors: Kudo Yoshiyuki , Hamada Shuichi 
Published: July 2006

Abstract
Heptathiazocine was pyrolyzed into ammonia, tetrasulfur tetranitride, and tetrasulfur dinitride above 383 K in an argon atmosphere; then, the latter two intermediates finally degraded into sulfur and nitrogen. According to the stoichiometric correlation among the final pyrolytic products, an overall pyrolysis can be expressed as: S7NH=7/8 S8+1/3 N2+1/3 NH3. The differential scanning calorimetry of heptathiazocine gave the standard enthalpy of the formation as 89.3±1.1 kJ mol−1 by combining the enthalpy change of the pyrolysis with its molar heat capacity and known thermodynamic data of the concerned species. The standard enthalpies of the formation of this compound were also calculated as being 93 and 91 kJ mol−1 on the basis of Sanderson’s method, assuming that hydrogen bonds were negligible in the crystal (which were comparable to that observed in this work).
Redox-Photosensitized Reactions. XV. Photosensitized and Direct Photolytic Isomerizations of the Tetrahydro Dimers of 1-Benzylnicotinamide
Authors: Ishitani Osamu , Yanagida Shozo , Takamuku Setsuo , Pac Chyongjin 
Published: July 2006

Abstract
The photosensitization by either [ReBr(bpy)(CO)3] or [Ru(bpy)3]2+ (bpy=2,2′-bipyridine) resulted in the isomerization of 1,1′dibenzyl-1,1′,4,4′-tetrahydro-4,4′-binicotinamide (1) and 1,1′-dibenzyl-1,1′-tetrahydro-4,6′-binicotinamide (2) to give a common mixture of 1, 2, and the diastereoisomer of 2 (3) in a 2:2:1 ratio at a photostationary state, while either direct photoexcitation or thermal activation effected only the isomerization of 2 to 1 but not at all the retro isomerization.
The Synthesis of (15R)-Coleon C and (15S)-Coleon C
Authors: Matsumoto Takashi , Imai Sachihiko , Yoshinari Takashi 
Published: July 2006

Abstract
(15R)-11,16-Dihydroxy-12-methoxymethoxy-8,11,13-abietatrien-7-one and its (15S)-epimer prepared from a C-15 epimeric mixture of 12-methoxy-8,11,13-abietatrien-16-ol, were transformed into (15R)-6,11,12,14,16-pentahydroxy-5,8,11,13-abietatetraen-7-one and its (15S)-epimer; these were identical with natural (15R)-coleon C and (15S)-coleon C, respectively.
Pyrolysis of Sulfoxide Bearing Electron-Withdrawing Substituents on β-Position in S-Ethyl Group of Ethyl Phenyl Sulfoxide
Authors: Yoshimura Toshiaki , Yoshizawa Masaki , Tsukurimichi Eiichi 
Published: July 2006

Abstract
In order to obtain information concerning the reaction mechanism of the pyrolysis of a sulfoxide bearing an electron-withdrawing substituent on the β-position in the S-ethyl group of ethyl phenyl sulfoxide, 2-(substituted phenyl)ethyl aryl sulfoxides(1) and 2-cyanoethyl (substituted phenyl) sulfoxides(2) were pyrolyzed. The rate-enhancing effect of the β-phenyl group of 1 was small. The activation enthalpy and entropy of 1 were found to be 110 kJ mol−1 and −45 JK−1 mol−1, respectively. Hammett plots for 1 gave positive trends for the substituents, both on the β-phenyl group (ρ=0.76) and on the S-phenyl group (ρ=0.32), though the ρ-value of the latter was about half of the former. On the other hand, the Hammett plot for 2 did not give a straight line, but a concave curve in which a series of substituents from the p-OCH3 to p-Cl groups gave a negative trend (ρ=−0.49), while the p-NO2 group afforded a positive trend. The pyrolytic rate of 2 was found to be about 23-times faster than that of 1 at 100 °C. The kinetic isotope effect for β-position hydrogen in the β-phenylethyl group of 1 was considerably large (kH⁄kD=4.3). From the obtained results, it was suggested that the pyrolysis of 1 and 2 proceeds via a nearly carbanion-like mechanism in a five-membered cyclic transition state.
Synthesis and Electrochemical Properties of 3-(3,6-Dioxo-1,4-cyclohexadienyl)methyl-p-tropoquinone. Analysis of a Four-Electron Redox System by Cyclic Voltammetry
Authors: Mori Akira , Goto Yasutomo , Takeshita Hitoshi 
Published: July 2006

Abstract
A methylene-linked bisquinone, 3-(3,6-dioxo-1,4-cyclohexadienyl)methyl-p-tropoquinone, was prepared from 2,5-bis(arylmethoxy)tropone by consecutive reaction, a homolytic rearrangement, subsequent debenzylation, and a DDQ–dehydrogenation. According to cyclic voltammetry, this four-electron redox system was operative, in sharp contrast to the case of the benzenoid bisquinones, via four successive one-electron transfer processes. Two other tropolone derivatives carrying p-benzoquinone segment were also prepared by a similar procedure. The first reduction potentials of these benzoquinones showed a slight enhancement by intramolecular hydrogen bonding.
Preparation of 2-Alkenylsilanes and 2-Alkenylstannanes by the Reaction of 2-Alkenyl-1,1-cyclopropanedicarboxylate Esters with PhMe2SiAlEt2 and (Ph3Sn)2Zn. Generation of 2-Alkenyl-3-cyclopentene-1,1-dicarboxylates via Alkenyl Substituted π-Allylpalladium Complexes Derived from Dienylsilanes and [PdCl2(CH3CN)2]
Authors: Fugami Keigo , Oshima Koichiro , Utimoto Kiitiro , Nozaki Hitosi 
Published: July 2006

Abstract
Reaction of 2-vinyl-1,1-cyclopropanedicarboxylate with PhMe2SiAlEt2, PhMe2SiZnEt2Li, or (Ph3Sn)2Zn gave 1,7-homoconjugate addition products, 2-alkenylsilanes or 2-alkenylstannanes. In a similar fashion, 2-(1,3-butadienyl)-1,1-cyclopropanedicarboxylate provided the corresponding 1,9-homoconjugate adducts, dienylsilanes or dienylstannanes. The adducts were converted into π-allylpalladium complexes by means of [PdCl2(CH3CN)2]. Treatment of the alkenyl-substituted π-allylpalladium complexes derived from dienylsilanes and [PdCl2(CH3CN)2] with bases such as PPh3 or Na2CO3 gave 2-alkenyl-3-cyclopentene-1,1-dicarboxylates. In contrast, the reaction of the π-allylpalladiums generated from 2-alkenylsilanes and [PdCl2(CH3CN)2] with the bases resulted in the formation of original vinylcyclopropane derivatives.
Novel Effect of Additives on the Quenching Mechanism of the Excited State of Copolymer-Pendant [Ru(bpy)3]2+ by Methylviologen in Methyl Alcohol
Authors: Kaneko Masao , Hou Xiao-Huai , Yamada Akira 
Published: July 2006

Abstract
The quenching of the excited state of acrylic acid copolymer-pendant [Ru(bpy)3]2+ by methylviologen (MV2+) was studied in methyl alcohol. The Stern–Volmer plots for the quenching showed a line or a curve (downward or upward) depending on the additive such as acid, alkali, or neutral salt in methyl alcohol. This behavior in methyl alcohol is entirely different from that in water where only dynamic quenching occurs. The behaviors in alcohol were analyzed by assuming stepwise binding of MV2+ into the domains around the Ru complex formed by the dissociated carboxylates and by considering dynamic as well as static quenching models. The one kind of photochemical reaction system showed four different quenching mechanisms induced by the additives.
Preferential Solvation of Ni(II) in Water–Solvent Mixtures from 13C NMR Paramagnetic Relaxation Rate
Authors: Kobayashi Kanya , Yokoi Masatoki , Kuroda Shigeki , Kubota Eiji 
Published: July 2006

Abstract
13C NMR spin-lattice relaxation time of carbon atom on methanol, ethanol, 1-propanol, and dimethyl sulfoxide molecules has been measured for solutions of Ni(ClO4)2 in these solvents and their mixtures with water. The comparison of the NMR data for solutions with aqueous mixtures and pure solvents gave the number of organic solvent molecules that locate in the first coordination sphere of Ni2+ ion. The result shows that Ni2+ ion is preferentially hydrated in water–alcohol systems, while in water–dimethyl sulfoxide system, the ion is solvated preferentially with dimethyl sulfoxide.
1H and 13C NMR Studies of Formation and Molecular Dynamics of Methylated-Cyclodextrin Inclusion Complexes with Phenylalanine
Authors: Inoue Yoshio , Kuan Fu-Hua , Chûjô Riichiro 
Published: July 2006

Abstract
The formation and the molecular dynamics of the host-guest inclusion complexes in aqueous solution have been studied for hosts α- and permethylated α-cyclodextrin and permethylated β-cyclodextrin and guest phenylalanine by 1H and 13C NMR spectroscopy. The changes in 1H chemical shift, 1H spin-coupling constant, and 13C spin-lattice relaxation time for the guest phenylalanine on addition of the host cyclodextrin show that they form the inclusion complexes in a similar manner, that is, by insertion of the guest’s phenyl ring into the host’s cavity. The strength of the host–guest dynamic coupling varies with the cavity size of cyclodextrins.
Relations between Gas-Phase Stepwise and Bulk Solvation of Cl− with Water and Aliphatic Alcohols
Authors: Hiraoka Kenzo 
Published: July 2006

Abstract
Higher order clustering reactions of Cl− with H2O and ROH for ROH=CH3OH, C2H5OH, and n-C3H7OH were measured in the gas phase with the pulsed electron-beam mass spectrometer. The general trend is found that the obtained −ΔHn−1,n° and −ΔSn−1,n° increase in the order H2O&lt;CH3OH&lt;C2H5OH&lt;n-C3H7OH. This order is just the opposite to the free energies of solvation of Cl−. This is due to the increasingly more unfavorable entropy changes for the solvation of Cl− in the order H2O&lt;CH3OH&lt;C2H5OH&lt;n-C3H7OH. This is clearly manifested on the increasing entropy changes −ΔSn−1,n° for the measured gas-phase clustering reactions for higher alcohols.
Development of Functionalized Materials Using Organometallic Compounds. IV. Thermal Residual Stresses during the Fabrication of a Ni-Coated Continuous Carbon Fiber Aluminum Composites
Authors: Mikata Yozo , Takahashi Tamotsu , Su Shuenn-Kung , Uchida Yasuzo 
Published: July 2006

Abstract
The thermal residual stresses during the fabrication of a Ni-coated carbon fiber composite are calculated by using two- and four-concentric-circular-cylinders models. The advantage of the CDL (chemical deposition in liquid phase) coating method at low temperature (200 °C), which is using organonickel compounds such as Ni(cod)2 (cod=1,5-cyclooctadiene), over the conventional melted Ni-coating method (1453 °C) has been definitely confirmed from the crack prevention viewpoint.
Zirconium–Bis(triethylamine): A New Class of Chelate Ion and Anion Exchanger
Authors: Rawat Jagdish Prasad , Alam Masood , Aziz Hasan M Abdul , Singh Balbir 
Published: July 2006

Abstract
A new inorganic ion exchanger, zirconium–bis(triethylamine) has been synthesized. The material has been studied for its anion exchange capacity, sorption capacity, Kd values, composition, infrared spectrum and thermodynamic behavior. Analytically important separation of anions have been achieved. Ion exchange equilibria of Cr2O72−, CrO42−, SO42−, S2O32−, and MnO4− systems have been studied at 30, 40, 45, and 60 °C. The exchange isotherms have been measured for both forward and backward reactions with solutions of ionic strength 0.10 by batch process. The isotherms showed S shaped curves. The overall thermodynamic data are also calculated.
Synthesis and Characterization of New Three-Component Ion-Exchange Material: Zirconium(IV) Selenophosphate
Authors: Qureshi Saidul Zafar , Rahman Nafisur 
Published: July 2006

Abstract
Zirconium(IV) selenophosphate has been prepared by adding a mixture which is 0.05 M in sodium selenite and 0.05 M in orthophosphoric acid to a 0.05 M solution of zirconium(IV) bis(nitrate) oxide in different volume ratios at pH 1. Its ion-exchange capacity, thermal and chemical stability, pH titration curves, and chemical composition were studied. Adsorption of some of the metal ions in different solvent systems has been studied. The effect of particle size on the sorption behavior of metal ions has also been studied. The analytical importance of this material has been demonstrated by achieving the eleven quaternary separations of metal ions. A comparison of ion-exchange properties of this material has also been made with some other ion-exchangers.
Titanium Determination under High-Sensitivity Conditions with 2-(5-Chloro-2-pyridylazo)-5-dimethylaminophenol. II. Ternary Compounds of Ti(IV)–H2O2–5-ClDMPAP
Authors: Marini Héctor José , Antón Rosa Isabel , Olsina Roberto Antonio 
Published: July 2006

Abstract
Ti(IV) together with pyridylazo-type reagents and other molecular compounds form ternary complexes that may stand as the basis for analytical methods designed for the quantitative determination of the metal. This paper reports the results obtained by the use of the system Ti(IV)–H2O2–5-ClDMPAP in aqueous ethanolic solutions, and application to routine analyses of Ti(IV) in various types of samples. The spectral characteristics of the complexes formed, the pH ranges appropriate for their formation, ethanol influence, composition and stability have been studied. The complex selected for this analytical work is formed between pH 2.5 and 6.5 with a 1:2:2 Ti(IV)–H2O2–5-ClDMPAP molar ratio. The system fulfils Beer’s law up to a Ti(IV) concentration of 0.7 ppm, working at λmax 534 nm. The molar absorptivity and Sandell index are 4.59×104 dm3 mol−1 cm−1 and 0.0010 μg cm−2 respectively
Synthesis and Fluorescence Analysis of 3-Substituted 7-Dialkylamino-2H-1,4-benzoxazin-2-ones
Authors: Trebaul Claude , Roncali Jean , Garnier Francis , Guglielmetti Robert 
Published: July 2006

Abstract
New benzoxazinone type dyes have been synthesized by the reaction of α-keto esters on 2-amino-5-(dialkylamino)phenols. The obtained 7-dialkylamino-2H-1,4-benzoxazin-2-ones show a strong fluorescence and a large Stokes shift, reaching 183 nm. An effect of 15 various substituents in position 3, together with a solvent effect have been characterized on their absorption and emission bands. Linear free energy relationships allow the tuning of their spectroscopic characteristics over a large spectral range.
A Simple and Convenient Method for the Synthesis of Iminomethylene Analogs of Peptides
Authors: Oyamada Hidekazu , Ueki Masaaki 
Published: July 2006

Abstract
The synthesis of pseudopeptides in which a part of the peptide bonds has been replaced by other isosteric bonds has been studied in order to obtain long-lasting peptide drugs and also to study the structure-activity relationships of peptides with biological activity. A simple and convenient method for the synthesis of pseudo[CH2–NH]peptides was established by improving the conditions for the selective reduction of the peptide bond of N-protected dipeptide esters by borane. Among the ester residues investigated, the t-butyl ester gave the best result. During reactions no racemization occurred. [l-Pheψ[CH2–NH]l-Leu4−5]leucineenkephalin was synthesized in good yield starting from N-benzyloxycarbonyl-l-phenylalanyl-l-leucine t-butyl ester.
The Addition Reaction of Benzynes Generated Electrochemically from Dihalobenzenes with Tertiary Amines
Authors: Egashira Naoyoshi , Takenaga Jun , Hori Fumiaki 
Published: July 2006

Abstract
The electroreduction of dihalobenzenes was carried out in the presence of tertiary amines as benzyne acceptors in DMF–TBAP, giving the addition products in yields of more than 10%. For o-dibromobenzene, the yield of the addition product, N-phenylpiperidine, increased to 21% in the presence of N-ethylpiperidine.
An Application of Factor Analysis to the Electronic Spectra of Iodine in Mixed Solvents
Authors: Nakanishi Koichiro , Maya Kenkichi , Howery D G 
Published: July 2006

Abstract
The electronic spectra of iodine diluted in three kinds of mixed solvents, ethanol–heptane, 1,4-dioxane–cyclohexane, and tetrahydrofuran–cyclohexane have been measured as a function of molar composition in mixed solvents and a factor analysis technique has been applied to interpret the results. The number of different iodine-solvent complexes in ethanol solutions is smaller than that in ether solutions.
Crystal Structure of (+)490CDmer-Bis{bis(3-aminopropyl)aminecobalt(III)} Hexacyanocobaltate(III) Dihydrate, (+)490CDmer-[Co(dpt)2][Co(CN)6]·2H2O
Authors: Ishii Minoru , Umehara Michiko , Harada Kazumasa , Nakahara Masayoshi 
Published: July 2006

Abstract
The structure of optically active title compound was determined by X-ray diffraction. The absolute configuration is trans-δ-NH. A pair of two-fused six-membered rings is extended. The geometry of the octahedron is distorted by the presence of the six-membered chelate rings.
The Synthesis of Heteroaromatic Cations Containing Sulfur or Selenium Atoms
Authors: Shibuya Isao , Nakanishi Hiroshi 
Published: July 2006

Abstract
The dialkylamino-substituted heteroaromatic cations, such as 1,2,4-diselenazolium, 1,2-diselenolium, 1,3,5-selenadiazinium, and 1,3-selenazinium cations, were newly synthesized, and their S-analogs were also obtained through similar procedures.
Substitution Reaction of Organic Halide by Trimethylsilyl Isothiocyanate: Formation of Thiocyanate and Its Rearrangement to Isothiocyanate
Authors: Nishiyama Kozaburo , Oba Makoto 
Published: July 2006

Abstract
The reaction of organic halide with trimethylsilyl isothiocyanate (TMSTC) gave thiocyanate 1 and its isomerized isothiocyanate 2. Details of the substituion and the isomerization reactions were examined.
Normal- and High-Pressure Diels–Alder Reactions of p-Tropoquinone with Furans
Authors: Tsuda Tohru , Sugiyama Shigeru , Mori Akira , Takeshita Hitoshi 
Published: July 2006

Abstract
The Diels–Alder reactions of p-tropoquinone with furans were investigated under normal- and high-pressure conditions. With furan or 2-methylfuran, no cycloadduct was obtained at all, but with 2-methoxyfuran, a double Michael adduct was isolated from the reaction under the atmospheric pressure, and its structure was elucidated mainly by 1H NMR analysis. With 3,4-dimethoxyfuran, an exo-1 : 1-adduct and its further reacted 2 : 1-adduct were isolated.
Substitution-Type Thermal 1,2-Rearrangement. Synthesis of Chiral β-Aryl(or Alkenyl) α-Oxo Nitrile Acetal
Authors: Honda Yutaka , Tsuchihashi Gen-ichi 
Published: July 2006

Abstract
Title compound was synthesized via a substitution-type thermal 1,2-rearrangement accompanied by introduction of a cyano group, and derived into the corresponding aldehyde, alkanoic acid, and amide.
Some Unusual Phase Transitions of Nickel(II) Diamine Complexes
Authors: Roy Sukumar , De Goutam , Chaudhuri Nirmalendu Ray 
Published: July 2006

Abstract
[NiX2(tn)2], (tn=1,3-propanediamine; X2=Br2, SO4, or SeO4) undergoes phase transitions upon heating and reverts to their original structure upon cooling. These transitions have been investigated by differential scanning calorimetry and infrared spectroscopy. Earlier, we reported the thermally induced phase transitions of nickel(II) diamine complexes. Most of these phase transitions are time dependent reversible type and the extent of reversibility are found to be catalyzed by humid atmosphere. [Ni(tn)3]X2 and [NiX2(tn)2]·H2O (X2=Cl2, Br2, SO4 etc.) were found to decompose through bis and monodiamine steps. We isolated and characterized all the possible intermediates. But we did not carry out thermal studies of these intermediates from the room temperature. This communication reports some new and interesting reversible phase transitions of [NiX2(tn)2] (X2=Br2, SO4, or SeO4).