bluuebunny/crossref_metadata_2025_split huggingface dataset:
Infrared Absorption Study of Peptide Fragments of Human Hemoglobin α-Chain (123–136) in the Solid State
Authors: Narita Mitsuaki , Doi Masamitsu , Takegahara Hitoshi 
Published: July 2006

Abstract
In order to evaluate the influence of polar amino acid residues on peptide conformations, IR absorption spectroscopic analysis of peptide fragments of human hemoglobin α-chain (123–136) and Boc–Leun–OBzl (n=3–6,9, and 12) was performed in the solid state. The polar amino acid residues involved in the peptide fragments are in the following: Asp(OBzl), Lys(Z), Ser(Bzl), and Thr(Bzl). Regardless of the amino acid composition, all of the peptides equal to or larger than a pentapeptide level exhibited a high potential for the formation of a β-sheet structure in the solid state. Conformational behaviors of peptides having polar amino acid residues are similar to those of Boc–Leun–OBzl, indicating that polar side chains can not cause disturbance of the formation of β-sheet structures. The fine relationship among the conformation, solubility, and 〈Pc〉 value of the peptide fragments strongly supports the propriety of the solubility prediction method for peptide intermediates. The influence of shear stress on peptide conformations in the solid state was also investigated precisely, and it was suggested that a heptapeptide size had the potential for the development of a helical structure in the solid state.
Synthesis of (Diethoxyphosphoryl)acetonitrile Oxide and Its Cycloaddition to Olefins. Synthetic Applications to 3,5-Disubstituted 2-Isoxazolines
Authors: Tsuge Otohiko , Kanemasa Shuji , Suga Hiroyuki , Nakagawa Norihiko 
Published: July 2006

Abstract
(Diethoxyphosphoryl)acetonitrile oxide undergoes regioselective cycloaddition to olefins leading to 3-[(diethoxyphosphoryl)methyl]-2-isoxazolines or -isoxazole. The phosphorus-stabilized carbanions generated by deprotonation of the cycloadducts can be utilized for the condensation with carbonyl compounds, alkylation, and oxidation with oxygen to provide 3,5-disubstituted 2-isoxazolines as useful synthetic building blocks. Raney nickel hydrogenolysis of 3-[(diethoxyphosphoryl)methyl]-2-isoxazolines gives β-hydroxy-β′-phosphoryl ketones bearing a variety of functional groups, which can be further converted into α,β-unsaturated β′-phosphoryl ketones.
Structure-Activity Relationship of a Heat-Stable Enterotoxin Produced by Yersinia enterocolitica
Authors: Yoshimura Shoko , Hidaka Yuji , Aimoto Saburo , Shimonishi Yasutsugu , Takeda Tae , Miwatani Toshio , Takeda Yoshifumi 
Published: July 2006

Abstract
Several shorter analogues of heat-stable enterotoxin (ST) produced by Yersinia enterocolitica were synthesized by a conventional method and their toxicities were examined by using suckling mice. The full enterotoxigenic activity of ST of Y. enterocolitica was found to be carried on a peptide, which consists of 13 amino acid residues from the 18th Cys to the C-terminal Cys and has a similar amino acid sequence to those of ST’s produced by enterotoxigenic Escherichia coli (S. Aimoto et al., Eur. J. Biochem., 129, 257 (1982)) and Vibrio cholerae non-01 (T. Takao et al., FEBS Lett., 193, 250 (1985)). The results imply that the structural elements for expression of the toxicity are present in the common amino acid sequences of ST’s of Y. enterocolitica, E. coli, and V. cholerae non-01.
The Structure of Graucin A, a New Bitter Limonoid from Evodia grauca Miq. (Rutaceae)
Authors: Nakatani Munehiro , Takao Hideki , Iwashita Takashi , Naoki Hideo , Hase Tsunao 
Published: July 2006

Abstract
Graucin A, a new bitter limonoid, has been isolated from the root bark of Evodia grauca Miq. as well as the known limonoids limonin, rutaevin and limonin diosphenol. Its structural and stereochemical assignments were made using NMR (COSY and NOESY), and CD spectroscopy, which indicated the uncommon 5β-H configuration of this new compound. Rutaevin was also recognized to be a 5β-H limonoid.
Electronic Structure of (BEDT–TTF)CuCl2 Complex
Authors: Tanaka Masashi , Kawamoto Atsushi , Tanaka Jiro , Sano Mitsuru , Enoki Toshiaki , Inokuchi Hiroo 
Published: July 2006

Abstract
The X-ray photoelectron spectra and the ESR spectra of the (BEDT–TTF)CuCl2 complex were taken. The analysis of the X-ray photoelectron spectra shows that the Cu atoms in (BEDT–TTF)CuCl2 are in a mixed-valence state consisting of mono and bivalent cations and the concentration ratio of Cu(I) and Cu(II) is determined to be 2:1. The ESR signals show the presence of the BEDT–TTF cation radical and Cu(II)Cl2. The temperature dependence of the magnetic susceptibility of these components were obtained from the ESR data.
Study of One-Dimensional Metal Complexes: K[Ni(mnt)2]·H2O and K[Pt(mnt)2]·H2O
Authors: Kutsumizu Shoichi , Kojima Norimichi , Ban Toshiro , Tsujikawa Ikuji 
Published: July 2006

Abstract
The crystal structure, electrical conductivity and electronic and IR absorption spectra of two metal complexes, K[Ni(mnt)2]·H2O and K[Pt(mnt)2]·H2O (mnt=1,2-dicyano-1,2-ethylenedithiolato, C4N2S22−) were investigated. These two metal complexes belong to orthorhombic system and the lattice constants are a=12.00 Å, b=28.85 Å, and c=3.90 Å for the Ni complex and a=12.11 Å, b=29.23 Å, and c=7.73 Å for the Pt complex. Despite the same stoichiometries and similar crystal structures, the conductivity of Pt complex is 103 times as high as that of the Ni complex. The difference in the conductivity between the Ni and Pt complexes may be explained from the density of the unpaired electron on the central metal. The effects of the central metal on the electrical conduction properties may not be negligible for this type of complexes.
Synthesis of 1,4-Diaminocyclitol Antibiotics. I. Synthesis of 4′-Hydroxyfortimicin D
Authors: Kanai Kazuaki , Sakamoto Itsuki , Miyamoto Yasunobu , Ogawa Seiichiro , Suami Tetsuo 
Published: July 2006

Abstract
The 4′-hydroxy analog of fortimicin D has been synthesized by condensation of 4-O-acetyl-2,6-bis(2,4-dinitrophenylamino)-2,3,6-trideoxy-α-d-ribo-hexopyranosyl chloride with a partially protected aminocyclitol, 1,2:4,5-di-N,O-carbonylfortamine B, followed by deprotection.
Ylide–Metal Complexes. XIII. An X-Ray Photoelectron Spectroscopic Study of Bis(dimethylsulfoxonium methylide)gold Chloride
Authors: Konno Hidetaka , Yamamoto Yoshihisa 
Published: July 2006

Abstract
Bis(dimethylsulfoxonium methylide)gold chloride, [(CH3)2S(O)CH2AuCH2S(O)(CH3)2]Cl, has been studied by X-ray photoelectron spectroscopy. The C 1s spectrum was separated into two peaks at EB=284.0 and 285.1 eV in a ratio of 1:2. The peak at 285.1 eV corresponds to the methyl carbons, and that at 284.0 eV is assigned to the electron-rich methylene carbon (or carbanion). The EB of Cl 2p3⁄2 agreed with that for chlorobis(triphenylphosphine)gold(I) and chlorobis(triphenylmethylenephosphorane)gold(I). The EB of Au 4f7⁄2 was 84.4 eV, suggesting the oxidation number +1. These results indicate that the structure of the title complex is (CH3)2S(O)CH2Au(Cl)CH2S(O)(CH3)2, and different from that reported previously.
Preparation, Structure, and Circular Dichroism Spectra of [Co(L1)(L2)]+-Type Complexes (L1=Iminodiacetato or N-Methyliminodiacetato and L2=3-Azapentane-1,5-diamine or 3-Methyl-3-azapentane-1,5-diamine)
Authors: Yasui Takaji , Okamoto Ken-ichi , Hidaka Jinsai , Ama Tomoharu , Kawaguchi Hiroshi 
Published: July 2006

Abstract
Three geometrical isomers (mer, u-fac, and s-fac) possible in each of [Co(ida)(mdien)]+ and [Co(mida)(mdien)]+ and u-fac isomer of [Co(mida)(dien)]+ (ida=iminodiacetate, mida=N-methyliminodiacetate, mdien=3-methyl-3-azapentane-1,5-diamine, and dien=3-azapentane-1,5-diamine) were newly prepared, and the u-fac isomers were optically resolved. The geometrical structures of these isomers were assigned on the basis of their absorption and 13C NMR spectral data. The crystal structure of (+)550CD-u-fac-[Co(ida)(mdien)]·(+)575CD-[Co(ox)2(en)]·6H2O was determined by X-ray diffraction method. The crystal is monoclinic, space group P21, a=15.793(6), b=12.855(3), c=7.070(2) Å, β=96.80(5)°, and Z=2. Both of the absolute configurations of the two complex ions take Λ configuration. The relationship between the absolute configurations and the CD spectral behaviors of the u-fac isomers is also discussed.
Behavior of the Heat of Formation in the Bismuth–Antimony System
Authors: Badawi Walid Ahmad 
Published: July 2006

Abstract
Calorimetric studies on the behavior of the heat of formation in the bismuth–antimony system have been carried out at eight different compositions (10–80 at-% Sb). Values of the enthalpy and excess enthalpy at those compositions have been determined and tabulated at even temperature intervals of 10 °C in the range 50 to 650 °C. The heat of formation at 200 °C is given through the equation:
H F=11.658x2−14.436x22+2.778x23
The heat of formation is positive and takes a maximum value (2556±11) J mol−1 at 50 at-% Sb. The heat of formation is larger than the heat of mixing. The excess over the value of the heat of mixing is attributed to the larger excess volume in the solid state.
Dissociation Constants of Some Amino Acid and Pyridinecarboxylic Acids in Ethanol–H2O Mixtures
Authors: Niazi M S K , Mollin J 
Published: July 2006

Abstract
The dissociation constants of nicotinic, picolinic, benzoic, and o-, m-, and p-aminobenzoic acids and those of glycine, dl-alanine, β-alanine, aniline, and pyridine were determined potentiometrically and spectrophotometrically in 0, 10, 30, 50, and 72% (w/w) ethanol–water mixtures at 25 °C at various ionic strengths (0.01–0.5 mol dm−3). The pK’s of benzoic, o-, m-, and p-aminobenzoic acids increased with increase of EtOH contents while those of nicotinic acid, picolinic acid, glycine, dl-alanine, and β-alanine passed through minimum (upto 30% w/w EtOH contents). The pK’s of aniline and pyridine were almost the same as those found in literature. The variation in pK’s with the solvent composition is discussed in terms of the free energy of transfer from H2O to EtOH–H2O mixtures. The zwitterion to neutral molecule ratio of these acids is also discussed in terms of variation of composition of mixtures.
Synthesis on 1,4-Diaminocyclitol Antibiotics. II. Synthesis of 7′-Propylfortimicin A
Authors: Kanai Kazuaki , Nishigaki Junji , Ogawa Seiichiro , Suami Tetsuo 
Published: July 2006

Abstract
7′-Propylfortimicin A has been synthesized by a condensation of newly prepared 1-O-acetyl-2,6-bis(2,4-dinitrophenylamino)-2,3,4,6,7,8,9,10-octadeoxy-l-lyxo-decopyranose with 2,5-di-O-benzoyl-1,4-bis-N-(methoxycarbonyl)fortamine B, followed by deprotection.
The Reactions of Alkoxyl Radicals with O2. IV. n-C4H9O Radicals
Authors: Morabito Paul , Heicklen Julian 
Published: July 2006

Abstract
n-C4H9ONO was photolyzed with 366 nm radiation at −8, 23, 55, 88, and 120 °C in the presence of NO, O2, and N2. The quantum yields of n-C3H7CHO, C2H5CHO, and CH3CHO were measured as a function of reaction conditions. The primary photolytic act produces n-C4H9O· radicals which can react with NO by two routes
n-C4H9O·+NO→n-C4H9ONO (2a)
→n-C3H7CHO+HNO (2b)
or isomerize via an internal H-atom abstraction
n-C4H9O·→I· (4)
where I· is the HOCH2CH2CH2CH2· radical, and ln(k4⁄k2, mol dm−3)=1.93±1.60–(4014±509)⁄T. If k2 is taken as 2.6×1010 dm3 mol−1 s−1, then log(k4, s−1)=11.25±0.69–(4014±509)⁄2.303T. In the presence of O2, n-C4H9O· radicals can also react with O2
n-C4H9O·+O2→n-C3H7CHO+HO2 (6)
with ln(k6⁄k2)=(−4.09±0.54)–(1178±176)⁄T. If k2=2.6×10−10 dm3 mol−1 s−1, then k6=4.5×108exp {(−1178±176)⁄T} dm3 mol−1 s−1. The radical I· is removed via
I·→CH3CHO+2CH2O+HO (12a)
→Undetected aldehydes+HO (12b)
I·+O2→n-C3H7CHO+HO (13a)
→C2H5CHO+HO (13b)
where these reactions are composites of a series of steps. The ratio k13a⁄k13b\simeq1.3±0.2 nearly independent of temperature. The ratio k12⁄k13 was not found very accurately, but is \simeq3×10−3 mol dm−3. There was no evidence for the oxidation of I· leading to dioxygenated products.
Support Effect of Zinc Oxide Catalyst on Synthesis of Methanol from CO2 and H2
Authors: Inoue Takashi , Iizuka Tokio , Tanabe Kozo 
Published: July 2006

Abstract
The synthesis of methanol from CO2+H2 was carried out at 340–400 °C under total pressure of 10 atm over ZnO supported on MgO, Al2O3, SiO2, TiO2, ZrO2, and Nb2O5. The ZnO/ZrO2 catalyst showed high activity and selectivity for methanol formation. The hydrogenation of CO2 was more selective for methanol synthesis than that of CO.
An Explanation of the Temperature Dependence of the Mössbauer Spectra of Mixed Valence Biferrocenium Derivatives with a (Valence-State) Order-Disorder Transition
Authors: Masuda Yuichi , Sano Hirotoshi 
Published: July 2006

Abstract
The temperature dependence of the quadrupole splitting values in the Mössbauer spectra for monooxidized biferrocenium derivatives is well explained in term of an order-disorder transition with regard to the valence state of two iron atoms in the cations.
Raman Spectra of the Organic Conductor, (TTM–TTF)I2.47
Authors: Ishii Kikujiro , Nakayama Hideyuki , Wu Peiji , Mori Takehiko , Enoki Toshiaki , Imaeda Kenichi , Saito Gunzi , Inokuchi Hiroo 
Published: July 2006

Abstract
The Raman spectra of a highly conductive molecular complex of the title were measured. The I3− symmetric stretching band and its well-known overtones were observed, indicating that the formula for this complex should be written as (TTM–TTF)(I3)0.823. A brief discussion is given comparing the spectra of the present complex with those of TMA–I–TCNQ and (BEDT–TTF)2I3 complexes.
The Brillouin Scattering of Highly Viscous Mixtures
Authors: Hashitani Ryuki , Koda Shinobu , Nomura Hiroyasu 
Published: July 2006

Abstract
The sound velocities of mixtures of tri-o-tolyl phosphate and diisobutyl phthalate were measured by means of the Brillouin scattering method in the temperature range from 214 to 333 K. The velocity dispersion was observed in the mixtures at temperatures from 273 to 323 K in the gigahertz region. The velocity dispersion was attributed to the structural relaxation, as in the case of pure highly viscous liquids. The reduced variable method proposed by Lamb et al. could not be applied to the storage moduli over wide frequency and temperature ranges. The relaxation curves of the reduced storage modulus obtained at room temperature, where the viscosity obeyed the Arrhenius equation, were well expressed by a single relaxation equation. The structural relaxation mechanism of the highly viscous liquids investigated here is related to the weak cooperative motions of molecules in the liquid state. The activation energy, ΔEr, obtained from the temperature dependences of the relaxation times was about a third of those estimated from the Arrhenius plots of the shear viscosities of the mixtures.
Homogeneous and Electrochemical Electron-Transfer Reaction of Nitrobenzene Anion Radical Dissolved in Nitrobenzene
Authors: Suga Kosaku , Aoyagui Shigeru 
Published: July 2006

Abstract
Nitrobenzene anion radical was stably prepared by the electrolytic reduction of nitrobenzene solution containing various kinds and amounts of tetraalkylammonium perchlorates. The rate constants of homogeneous electron-transfer reactions of these nitrobenzene anion radicals with nitrobenzene molecules as a solvent were determined by ESR method at various temperatures. These rate constants at 25 °C were about 107 dm3 mol−1 s−1 and comparable with the rate constant of electron-transfer reation between nitrobenzene and its anion radial in N,N-dimethylformamide. The quasi-first order rate constants evaluated from these rate constants were about 108 s−1 and were larger than the rate constants of the intramolecular electron-transfer reactions of the anion radical of bis(p-nitrophenyl) compounds except for bis(p-nitrophenyl)methane. The absorption spectrum of the solution of nitrobenzene anion radical in nitrobenzene containing 0.1 M tetrabutylammonium perchlorate or 0.1 M tetraethylammonium perchlorate showed an additional weak peak at about 800 or 900 nm as well as the ordinary peak. The light energies of these additional peaks were in good agreement with the energy values of the optical electron-transfer reactions evaluated according to the theory of Hush from the activation energies of corresponding thermal electron-transfer reactions. The rate constants of electrochemical electron-transfer reactions and the diffusion coefficients of nitrobenzene anion radical in nitrobenzene were also measured.
Ion/Molecule Reactions in Gaseous Isopropyl Alcohol
Authors: Hiraoka Kenzo , Takimoto Hajime , Yamabe Shinichi 
Published: July 2006

Abstract
The ion/molecule reactions observed in 4 Torr CH4 containing known small amounts of i-C3H7OH or i-C3H7OH/H2O mixture were studied over the temperature range 40–400 °C. The experiments were carried out using a pulsed electron beam mass spectrometer. At low temperatures (&lt;150 °C), the major ions are i-C3H7OH2+(i-C3H7OH)n. By increasing the temperature, the slow growth of ions with m⁄z=59, 85, and 101 is observed. These ions are assigned to (CH3)2COH+, (CH3)2CHC+(CH3)2, and C6H13O+, respectively. They are probably produced from reactions of i-C3H7+ with isopropyl alcohol. The (CH3)2COH+ ion may be produced from the electrophilic attack of i-C3H7+ onto the secondary carbon atom of i-C3H7OH. At high temperatures (≈400 °C), the (CH3)2COH+ ion becomes dominant. Acid-catalyzed dehydration of isopropyl alcohol, i-C3H7OH2++H2O→H3O+(H2O)+C3H6, is also observed. Ion/molecule reactions involved in the present experiment are discussed according to the frontier-orbital theory.
Structure Study of Supermonomolecular Layers in Langmuir–Blodgett Films. Surface Active Squarylium Dye–Fatty Acid Binary Mixed System
Authors: Matsumoto Mutsuyoshi , Nakamura Takayoshi , Tanaka Motoo , Sekiguchi Tatsuo , Komizu Hideo , Matsuzaki Sanae Y , Manda Eiichiro , Kawabata Yasujiro , Saito Mitsuyoshi , Iizima Sigeru , Sugi Michio 
Published: July 2006

Abstract
The structures of the Langmuir–Blodgett (LB) films of the ordinary mixed monolayer (LPF) and the supermonomolecular layer (HPF) of a surface active squarylium dye-icosanoic acid binary mixed system were examined by absorption spectroscopy. The absorption spectra of one unit layer of LPF with a molar mixing ratio ranging from 1/10 to 1/1 were almost the same, strongly suggesting that each component exists separately in the films. The LB films of two unit layers of LPF showed two peaks at 590 and 560 nm ascribed to intralayer and interlayer aggregates, respectively, besides the monomeric peak at 640 nm. The absorption spectra of one unit layer of HPF indicated a critical value of the mixing ratio 1/3.5 above which the 700-nm peak is observed. This peak is an indication of a multilayer consisting of pure 1 due to the interlayer interaction. The 560-nm peak observed for LPF is caused by a hindered interlayer interaction of the chromophores between the mixed monolayers.
Radiolysis of Methanol Adsorbed on Zeolite
Authors: Nakazato Chiyoko , Murayama Ryoji , Aoki Masayoshi , Masuda Takahiro 
Published: July 2006

Abstract
Radiolysis of methanol adsorbed on synthesized zeolite was investigated by means of product analysis. Molecular hydrogen, formaldehyde, and ethylene glycol are produced as major products. The G-value for the formation of H2 increases with increasing amount of methanol adsorbed on zeolite and approaches ca. 2.1 at about 10−2 mol of methanol per g of zeolite, where the coverage of methanol is approximately unity and G-values of ca. 1.0 are observed for formaldehyde and ethylene glycol. Addition of an electron scavenger causes decrease in G(H2). However, the hydrogen formation is not completely suppressed by N2O, SF6, or CCl4. Kinetics in solution is useful for the interpretation of results and allows the estimation of the G-value for the generation of electron in zeolite and of its relative reactivity toward methanol and some electron scavengers.
A Study of Inorganic Ion Exchangers. XI. The Hydrothermal Reactions of ZrOCl2 and M(H2PO4)2 (M=Mg, Ca, Sr, Ba)
Authors: Okabe Kiyomi , Kobayashi Etsuro 
Published: July 2006

Abstract
The possibility of the hydrothermal synthesis of layered zirconium phosphates containing various alkaline earth metals (abbreviated as ZrMP; M=Mg, Ca, Sr, Ba) has been studied from ZrOCl2 and M(HPO4)2, and their characteristics have been investigated. The optimum conditions for the synthesis of a highly crystalline product were as follows; the molar ratio of the starting materials of Ca(H2PO4)2 and ZrOCl2 was Ca/Zr=3, and the temperature of the hydrothermal reaction was in the range of 200–270 °C. By the hydrothermal reaction of ZrOCl2 and Mg(H2PO4)2, a new compound of ZrMg0.5H(PO4)2·H2O with a layer-spacing of 11.94 Å was obtained. Layered phosphate (ZrMP) was not obtained by the hydrothermal reaction of ZrOCl2 and Ba(H2PO4)2. The temperature range of the inter-layer dehydration of the layered phosphates (ZrMgP, ZrCaP, and ZrSrP) was similar to that of α-zirconium(IV) bis(hydrogenphosphate) (α-ZrP); i.e. the water in the interlayer was lost at 130–240 °C, and dehydro-condensation took place at a higher temperature above 340 °C. Zirconium phosphate containing Mg2+ or Ba2+ was not obtained by the ion exchange of the protons in α-ZrP with the alkaline earth metal cations (M2+) in MCl2, while Ca2+ and Sr2+ were exchanged with the protons. These alkaline earth metal ions except for Ba2+ were easily exchanged with H+ in α-ZrP, when NaOH was added. The layer-spacing of the Mg2+-exchanged zirconium phosphate was 9.6 Å, which was different from that of the hydrothermal product. The layer distances of Ca2+- or Sr2+-exchanged products were similar to those of the hydrothermal products.
Preparation and Properties of Cobalt(II) Hydroxide–(Sodium Fluoride Tetrasilicic Mica) Intercalation Complexes and of Highly Dispersed Cobalt on Mica
Authors: Ohtsuka Kunio , Koga Johji , Suda Mitsuru , Ono Mikiya , Takahashi Minoru 
Published: July 2006

Abstract
Cobalt(II) hydroxide–(sodium fluoride tetrasilicic mica) intercalation complexes were prepared by titrating cobalt(II) nitrate solutions in the presence of mica with sodium hydroxide under oxygen-free conditions. These complexes were characterized by chemical analysis, XRD, DTA-TGA, IR, and surface area measurements. These confirmed that the brucite-like cobalt(II) hydroxide sheet developed within the interlayer of the silicate. Cobalt atoms reduced at 400–700 °C by H2 migrated from the interlayer of the silicate to the external surface of these where highly dispersed cobalt particles were formed. Ultra-fine cobalt metals (50–200 Å) with a hexagonal close-packed form were prepared at 400 °C by H2. The degree of reduction and the grain diameter of cobalt increased with an increase of the reducing temperature and/or the reducing time.
Alkaline Hydrolysis of Inorganic cyclo-Polyphosphates
Authors: Kura Genichiro 
Published: July 2006

Abstract
The hydrolysis rates of inorganic cyclo-polyphosphates in alkaline solutions were determined. The rates in a NaOH solution were significantly faster than those in a (CH3)4NOH solution. Ion-pair formation between PO− and Na+ renders the P atom more positive by reducing the electron density around the atom and more susceptible to the nucleophilic attack by OH−. In a (CH3)4NOH solution, higher-membered cyclo-polyphosphates with a larger ring structure became rather stable. Arrhenius’ activation energy for each phosphate decreases in the order HCl&gt;NaOH&gt;(CH3)4NOH.