bluuebunny/crossref_metadata_2025_split huggingface dataset:
Classification of Phenothiazine Complexes by Structure and Electronic Properties
Authors: Kozawa Kozo , Hoshizaki Taketoshi , Uchida Tokiko 
Published: July 2006

Abstract
Donor-acceptor complexes were prepared, and their structures and electronic properties were observed. Donors were phenothiazine and its four derivatives, and acceptors were metallic chlorides (Lewis acids), iodine, and two π-type acceptors. By the absorption edge of diffuse reflection spectra (λE) and crystal structure, the complexes were classified into four groups. Groups I, II, and III correspond to the complexes with Lewis acids or iodine, and group IV consists of complexes with π-type acceptors. The summarized characteristics of each group are as follows. Group I: λE≤950 nm, complete charge transfer, insulator, and alternate arrangement of cations and anions. Group II: 1200 nm≤λE≤1700 nm, complete charge transfer, semiconductive behavior, and oligomeric or columnar arrangement of cation radicals. Group III: λE&gt;2500 nm, partial charge transfer, metallic conductor or semiconductor with small activation energy, and columnar arrangement. Group IV: λE≥1700 nm, and semiconductive behavior. Based on these classifications, we have proposed a mechanism for controlling the aggregate manner of cation radicals.
Synthetic Photochemistry. LVI. Photorearrangement of Dimethyl 2-Oxohomobarrelene-6,7-dicarboxylates
Authors: Mori Akira , Nukii Yasuhiro , Endo Akihiro , Takeshita Hitoshi 
Published: July 2006

Abstract
The direct irradiation of dimethyl 2-oxohomobarrelene-6,7-dicarboxylates in chloroform gave indanone derivatives. A benzophenone-sensitized reaction gave a new tricyclic compound, dimethyl 5-oxotricyclo[4.3.0.02,9]nona-3,7-diene-1,2-dicarboxylate, the formation of which was quenched by isoprene.
Synthesis of Benzo[1,2:4,5]dicycloheptene-1,9-dione via 6,7,12,13- Tetrahydro-7,12-methano-3H-cycloheptacyclodecene-3,14-dione and Its Protonation Behavior
Authors: Kato Masahiko , Mitsuda Masaru , Shibuya Takuji , Furuichi Kimiaki 
Published: July 2006

Abstract
6,7,12,13-Tetrahydro-7,12-methano-3H-cycloheptacyclodecene-3,14-dione has been synthesized starting from the [4+6]-cycloaddition product of the reaction of 3,4-bis(methylene)-7,7-dibromobicyclo-[4.1.0]heptane with tropone. The adducts were transformed to their epoxides, which were treated with trifluoroacetic acid to give the 3,14-dione. This was transformed to benzo[1,2:4,5]dicycloheptene-1,9-dione, bis(tropono)benzene, by two different methods: (1) by heating it with trichloroacetic acid and DDQ in toluene or (2) through bromination followed by heating in DMF. The 1,9-dione is protonated in coned sulfuric acid to give bis(hydroxytropylium) dication, while it is protonated mainly (&gt;80%) on the C-9 carbonyl oxygen and less (&lt;40%) on the C-1 carbonyl oxygen in deuteriochloroform containing trifluoroacetic acid.
Synthesis of Optically Active Substituted Cyclohexenones from Carbohydrates by Catalytic Ferrier Rearrangement
Authors: Chida Noritaka , Ohtsuka Masami , Ogura Katsuyuki , Ogawa Seiichiro 
Published: July 2006

Abstract
Conversion of hex-5-enopyranosides into substituted cyclohexanones (Ferrier rearrangement) was found to proceed efficiently with a catalytic amount of various mercury(II) salts at room temperature in a neutral solvent system. Among the mercury(II) salts tested, mercury(II) trifluoroacetate showed the highest activity. Four optically active cyclohexenones were prepared from hex-5-enopyranosides utilizing this method.
Benzophenone-Sensitized Photolysis of N,N-Dibenzyl-O-acylhydroxylamines. Mechanism of the Imine-Forming Radical Elimination Reaction
Authors: Sakurai Tadamitsu , Mizuno Hisashi , Kubota Tsuneari , Inoue Hiroyasu 
Published: July 2006

Abstract
Title hydroxylamines (1) undergo benzophenone-sensitized photolysis to give N-benzylidenebenzylamine (2), p-substituted benzoic acids (3), and monosubstituted benzenes (4) derived from decarboxylation of p-substituted benzoyloxyl radicals. Analysis of the linear Stern–Volmer plots, both for the sensitized photolysis of 1 and for the phosphorescence quenching of benzophenone by 1, demonstrates the participation of triplet 1 in this photolysis. The logarithm of the ratio (kr⁄kd), where kt is the rate constant for homolytic cleavage of the N–O bond in triplet 1 and kd is that for its deactivation, used as a measure of the triplet-state reactivities of 1, exhibited a good Hammett-type relationship against the substituent constant (σ) with a slope (ρ) of −0.75. This indicates the exclusive occurrence of homolysis of the N–O bond in the first excited triplet state of 1. Thus the decomposition of 1 activated by triplet benzophenone is classified as an imine-forming radical elimination. The results of deuterium isotope and micellar effects on the sensitized photolysis suggest that the “out-of-cage” products 4 are obtained by decarboxylation and subsequent hydrogen abstraction of p-substituted benzoyloxyl radicals which escaped from the triplet cage in competition with spin inversion to the singlet cage. In this singlet cage, hydrogen abstraction giving 2 and 3 and recombination affording the starting 1 were found to take place exclusively.
Discrimination of Rotational Isomers of Jet-Cooled Acetophenone Derivatives as Studied by Sensitized Phosphorescence Excitation Spectroscopy
Authors: Yamamoto Seiji , Hashimoto Nobuhisa , Ito Mitsuo 
Published: July 2006

Abstract
The S1(n,π*)←S0 and T(n,π*)←S0 sensitized phosphorescence excitation spectra of jet-cooled o- and m-substituted (fluoro- and methyl-) acetophenones have been measured. The two rotational isomers (O-cis and O-trans isomers) of each molecule arising from the orientation of the acetyl group with respect to o- or m-substituent have been discriminated. The energy difference in the 0–0 transition between the two isomers is less than 100 cm−1 for m-substituted acetophenone but more than 300 cm−1 for o-substituted acetophenone. The characteristic energy difference can be explained from the fact that the electronic excitation is localized on the C=O group.
Isotope Effects on the Reorientational Motion of Hydrated H2O Molecules in Alkali Metal Bromide Dilute Aqueous Solutions Studied by NMR Spectroscopy
Authors: Shimizu Akio , Taniguchi Yoshihiro 
Published: July 2006

Abstract
The spin-lattice relaxation times of 1H and 17O nuclei of hydrated H2O molecules in alkali metal bromide (LiBr, NaBr, KBr, and CsBr) dilute aqueous solutions in the concentration range from 0.2 to 1.0 mol kg−1 at 25 °C were measured by NMR spectroscopy. The reorientational correlation times for the intramolecular 1H–1H (τHH+) and 1H–17O (τOH+) axes, as well as the perpendicular axis (17O nuclei, τ17O+) to the molecular plane of a hydrated H2O molecule were determied. The two reorientational correlation times (τHH+ and τOH+) of pure H2O and hydrated H2O molecules in Li+, Na+, K+, and Cs+ ions were equal, respectively. Comparing previous data for hydrated D2O molecules with that calculated by using correction values (rHH, rOH, and quadrupolar constant) for H2O molecules, the ratios of τD+(D2O)/τOH(H2O) and τ17O+(D2O)/τ17O+(H2O) were found to be of the same order as η(D2O)/η(H2O), except for the τ17O+(D2O)/τ17O+(H2O) value for the Li+ ion.
Synthesis of Optically Active Polyamides Having Axially Dissymmetric 1,1′-Binaphthalene-2,2′-dicarboxylic Acid Component and Their Optical Resolution Ability as Chiral Adsorbent for HPLC
Authors: Tamai Yasufumi , Matsuzaka Yutaka , Ôi Shuichi , Miyano Sotaro 
Published: July 2006

Abstract
Optically active polyamides 4a–4c were synthesized from the polycondensation of axially dissymmetric 1,1′-binaphthalene-2,2′-dicarbonyl dichloride (2) with 1,4-benzenediamine, 1,6-hexanediamine, and 1,10-decanediamine, respectively. CD spectra of the polyamides 4a–4c are essentially the same as those of the corresponding model diamides 6a–6c prepared from 2 and benzenamine, 1-hexanamine, and 1-decanamine, respectively. This similarity indicates that the conformation of the 1,1′-binaphthalene-2,2′-dicarboxamide moieties of the polyamides 4a–4c in solution state are rather similar to those of the corresponding model diamides 6a–6c. Several axially chiral biaryl compounds and 3,5-dinitrophenylcarbamates (3,5-DNPCs) derived from 1-aryl-1-alkanols were resolved by HPLC equipped with the columns packed the chiral stationary phases (CSPs) prepared from 4a–4c adsorbed on spherical silica gel. A main control factor for the chiral discrimination seems to be the hydrogen bonding between the amide groups of the CSPs and the hydrogen-bonding sites of the atropisomeric biaryls. The donor–acceptor interaction between the binaphthalene moiety of the CSPs and the 3,5-dinitrobenzene moiety of the 3,5-DNPCs may also be important for the chiral discrimination of the 3,5-DNPCs.
Optical Properties of CdS Microcrystallite-Doped Al2O3 Thin Films Prepared by Rf-Sputtering
Authors: Tanahashi Ichiro , Yoshida Masaru , Mitsuyu Tsuneo 
Published: July 2006

Abstract
Al2O3 thin films containing CdS microcrystallites were successfully prepared by an rf-magnetron sputtering technique. Photoluminescence spectra of films exhibited blue band-edge emission at a higher energy than that of bulk CdS. The spectral change seems to arise from a zero-dimensional confinement of electrons and holes in CdS microcrystallites.
Synthesis and X-Ray Crystal Structure of the Dicopper(I) Complex of 2-(Diphenylphosphino)pyridine (Ph2Ppy). [Cu2(μ-Ph2Ppy)2(CH3CN)2](PF6)2
Authors: Maekawa Masahiko , Munakata Megumu , Kitagawa Susumu , Yonezawa Teijiro 
Published: July 2006

Abstract
The dicopper(I) complex with 2-(diphenylphosphino)pyridine (Ph2Ppy), [Cu2(μ-Ph2Ppy)2(CH3CN)2](PF6)2 has been prepared. The crystal structure has been determined crystallographically: Space group P\bar1, a=10,807(6), b=11.756(8), c=8.606(7) Å, α=90.36(6), β=95.98(5), γ=92.90(5)°, Z=1, R=0.067. The two copper atoms are bridged by two Ph2Ppy molecules in a head-to-tail arrangement, resulting in a rare staggered conformation of the eight-membered ring CU2P2N2C2, whose factor is concerned with the coordination numbers of the central metal atoms. 1H NMR studies show that the ligand of a CH3CN in the titled compound undergoes dissociation in acetone solution.
Demetalation of (5,10,15,20-Tetraphenylporphyrinato)iron Complexes: Effect of Substituents at the o-Positions of Phenyl Groups
Authors: Hasegawa Etsuo , Matsubuchi Eriko , Tsuchida Eishun 
Published: July 2006

Abstract
The demetalation of a series of (5,10,15,20-tetrahenylporphyrinato)iron(III) complexes having bulky substituents at the o-positions of phenyl rings was studied in acetic acid in the presence of iron(II) chloride and HCl. The reaction occurred simultaneously with the reduction of Fe(III) porphyrin to Fe(II) porphyrin, since no demetalation was observed without iron(II) chloride. The pseudo-first-order rate constants, which were determined spectrophotometrically, decreased with an increase in the bulkiness of the o-substituents on the phenyl rings. The atropisomeric structures of the products were determined by high-resolution NMR measurements.
Synthesis of Pyrazole Nucleosides Using Acylketene Dithioacetal Derivatives
Authors: Yokoyama Masataka , Ikuma Toshihiro , Sugasawa Sadataka , Togo Hideo 
Published: July 2006

Abstract
Several nucleosides bearing pyazole ring as the base moiety were synthesized by the reaction of d-ribofuranosylhydrazine or 2-deoxy-d-ribosuranosylhydrazine with easily available acylketene ditioacetal derivatives.
X-Ray Crystal Structures of Octahedral Diaquabis(N,N-dialkyl-ethylenediamine)nickel(II) Complexes Possessing Elongated Nickel(II)–Nitrogen Bonds along Axial Direction
Authors: Ihara Yoshinori , Satake Yasuhiro , Fujimoto Yumi , Senda Hitoshi , Suzuki Masatatsu , Uehara Akira 
Published: July 2006

Abstract
The structures of two diaquabis(N,N-dialkylethylenediamine)nickel(II) chlorides ([Ni(H2O)2(diamine)2]Cl2·nH2O) were determined by X-ray crystallographic studies, where diamine is N,N-dimethylethylenediamine(NN-dmen) or N,N-diethylethylenediamine (NN-deen). Both complexes are trans and crystallize in the monoclinic space group P21⁄n. The unit cell parameters of the NN-dmen complex, NiCl2C8N4O2H32, are a=7.531(1), b=13.092(1), c=9.591 Å, β=107.76(1)°, and Z=2, and those of the NN-deen complex, NiCl2C12N4O2H36, are a=9.154(1), b=8.692(1), c=12.395(2) Å, β=104.46(1)°, and Z=2. In trans-[Ni(H2O)2(NN-dmen)2]Cl2·2H2O and trans-[Ni(H2O)2(NN-deen)2]Cl2, the Ni–NMe2 and Ni–NEt2 bond distances (2.183 and 2.271 Å) are much longer than the Ni–NH2 distances (2.078 and 2.064 Å), forming tetragonally distorted octahedrons with four close in-plane neighbors(N2O2) and two remote axial ones(N2). It is apparent that this distortion originates from the steric requirement of N-substituted groups. Such a distortion significantly affects the electronic spectra of these complexes.
Chromatographic Optical Resolution Based on the Chiral Discrimination between Ions of the Same Sign, Anionic Cobalt(III) Complex Racemates and Anionic Selector [Sb2(d-tart)2]2−
Authors: Koine Norio 
Published: July 2006

Abstract
Column chromatographic optical resolutions of twenty-six typical univalent anionic cobalt(III) complexes, e.g., [Co(edta)]− and fac-[Co(NO2)3(edma)]−, were carried out, using as a chiral eluent an aqueous solution of [Sb2(d-tart)2]2− on a strongly basic anion exchanger, where edta=ethylenediamine-N,N,N′,N′-tetraacetate(4-), edma=ethylenediamine-N-acetate(1-), and d-tart=d-tartrate(4-). The racemates were resolved with separation factors comparable to those obtained in conventional resolutions by use of cationic selectors. From a comparison of elution orders of enantiomers and separation factors obtained for the racemates, a chiral discrimination mechanism without direct contact between the racemate and selector was proposed.
Reactions of 2-Aminoazulenes with Electron-Deficient Acetylenes
Authors: Abe Noritaka 
Published: July 2006

Abstract
2-Aminoazulene (1a) reacted with dimethyl acetylenedicarboxylate (DMAD) to give dimethyl 1,2-azulenedicarboxylate, tetramethyl 2,2′-(2-amino-1,3-azulenediyl)bis[fumarate], and dimethyl 2-(4-methoxycarbonyl-2-oxo-l,2-dihydroazuleno[2,1-b]pyridin-10-yl)fumarate. The reaction of ethyl 2-amino-1-azulenecarboxylate (1b) with DMAD gave dimethyl 2-(2-amino-3-ethoxycarbonyl-1-azulenyl)fumarate and 10-ethyl 4-methyl 2-oxo-1,2-dihydroazuleno[2,1-b]pyridine-4,10-dicarboxylate (8a). The treatment of 8a with phosphoryl chloride gave the 2-chloroazuleno[2,1-b]pyridine derivative. Reactions of 1a and 1b with methyl propiolate gave corresponding Michael adducts and the azuleno[2,1-b]pyridin-3(4H)-one derivatives. Reactions of 1a and 1b with dibenzoylacetylene gave 4-benzoyl-2-phenylazuleno[2,1-b]pyridine derivatives.
Strong Acid Sites Created on Small–Sized Anatase
Authors: Nakabayashi Hirotoshi , Kakuta Noriyoshi , Ueno Akifumi 
Published: July 2006

Abstract
The acid properties of anatase having different crystalline sizes were estimated by measuring the temperature-programmed desorption (TPD) of ammonia as well as the infrared spectrum of adsorbed pyridine at elevated temperature. The size-controlled anatase was prepared by hydrolysis of the titanium tetraisopropoxide dissolved in propyl alcohol using various amounts of distilled water. The acid properties of the anatase were confirmed to be strongly affected by the crystalline size. Especially, the strength of acid sites was found to remarkably increase with a decrease in the crystalline size. The specific activity and the activation energy for 1-butene isomerization on the anatase also depended on the crystalline size. The generation of strong acid sites on the surface is discussed in terms of the crystalline size.
Intramolecular Electron Transfer and SN2 Reactions in the Radical Anions of 1-Benzoyl-ω-haloalkane Studied by Pulse Radiolysis
Authors: Kimura Norio , Takamuku Setsuo 
Published: July 2006

Abstract
A one-electron reduction of 1-benzoyl-ω-haloalkane (Cl, Br, I) by solvated electrons and a subsequent intramolecular reaction of the radical anions, thus formed, have been investigated by using a pulse radiolysis technique. The reaction mechanism, electron transfer (ET) or SN2, and the rate constants were found to change as a function of the nature of the halide and the methylene chain length of the substrate. Although the order of reactivity based on leaving halogen atoms was I, Br, and Cl, the ease of the SN2 reaction was found to be in the order Cl&gt;Br&gt;I. In addition, the reaction rates were also affected by the polarity of the solvent used. On the basis of these results, it is discussed how the ET–SN2 dichotomy takes place.
Effects of Temperature and Pressure on the Charge-Transfer Complex Formation through Hydrogen Bonding and Ionization Reactions between 2,6-Dibromo-4-[(3,5-dibromo-4-hydroxyphenyl)(2-ethoxycarbonylphenyl)methylene]-2,5-cyclohexadien-1-one and Amines
Authors: Nishimura Norio , Osawa Yoshihiro , Kuramoto Kohji , Sukemichi Kazuo 
Published: July 2006

Abstract
The effects of temperature and pressure on the formation of charge-transfer (CT) complexes between 2,6-dibromo-4-[(3,5-dibromo-4-hydroxyphenyl)(2-ethoxycarbonylphenyl)methylene]2,5-cyclohexadien-1-one (TBPE) and amines in nonpolar solvents have been studied, and the thermodynamic parameters estimated. It was found that the heat of formation (ΔH°) as well as the reaction volume (ΔV°) are largely negative, compared with those for ordinary CT complex formation. The electronic spectra in the visible region due to the outer CT complexes are well-characterized for primary and secondary amines in nonpolar solvents that have no proton-donating/-accepting nature. In other cases, the CT spectra are broad. Ionization of TBPE in polar solvents takes place as evidenced by the electronic spectrum of TBPE anion. However, ΔH° as well as ΔV° are unusually small. When Proton Sponge is used in nonpolar solvents, ion pairs are formed. In this case, ΔH° and ΔV° are largely negative as expected.
The Pitzer Formalism vis-à-vis the Mixture Rule for the Estimation of Apparent Molal Volumes of Aqueous NaCl–KCl, NaCl–KBr, and NaCl–K2SO4 Mixtures at 298.15 K
Authors: Mahapatra Prafulla , Bhattacharyya Moni Mohan , Sengupta Mihir 
Published: July 2006

Abstract
The density data reported by Wirth for aqueous solutions of KCl, KBr, and K2SO4 in NaCl solutions of five different fixed concentrations at 298.15 K have been used to calculate the apparent molal volumes of the mixtures; the results have been compared with those calculated by the Pitzer formalism as also the Young and Smith’s mixture rule.
Synthesis, Crystal Structure, and Property of Novel Tetranuclear Nickel(II) Complex with Multidentate Ligand 7-[(3,5-Dichloro-2-pyridyl)azo]-8-hydroxyquinoline-5-sulfonic Acid
Authors: Huang Hu , Kai Fumiaki , Asai Yoshifumi , Hirohata Masaaki , Nakamura Masaaki 
Published: July 2006

Abstract
Reaction of nickel(II) perchlorate with the title ligand (Hpahqs) in aqueous solution followed by standing for about six months produces a complex having the formulation [Ni4(pahqs)4(H2O)4]·20H2O. A single crystal X-ray analysis revealed that the complex contained the four nickel(II) and four ligand molecules and showed a novel structure of oxygen bridged tetranuclear nickel(II) complex. Crystal data: triclinic, space group P\bar1, a=17.884(7), b=22.071(8), c=12.819(8) Å, α=100.77(4)°, β=92.55(4)°, γ=71.46(4)°, Z=2. Except one N atom in each azo-group, all the other donor atoms in the ligand were fully used in coordination to nickel(II), forming either N,N,O- or N,O-chelate rings, simultaneously. The geometry around each of the four nickel(II) was distorted octahedron. The bond lengths of N1–N(N atoms in N,N,O-terdentate moieties) were elongated compared with those of the corresponding complex, and the lengths of N1–N(N atoms in quinoline rings) were kept almost similar values to those of the Ni(II)-8-hydroxyquinoline complex. The bond lengths of Ni–O were elongated compared with those of the nickel(II) complexes with either N,N,O- or N,O-chelate rings, resulting in the contraction of the angles of N–Ni–N or N–Ni–O. The angles of Ni–O–Ni around four nickel(II) sites were ca. 140°. The antiferromagnetic exchange interaction was operating between the four nickel(II) via bridging oxygen atoms.
Reversed Phase Extraction Chromatographic Separation of Germanium with Aliquat 336S from Citric Acid
Authors: Sahoo Sarat Kumar 
Published: July 2006

Abstract
Germanium was extracted from 0.005 mol dm−3 citric acid at a pH between 2.5 and 6.5 on a column of silica gel coated with Aliquat 336S as the stationary phase. Germanium was then stripped with 0.5 mol dm−3 hydrochloric acid and determined spectrophotometrically as its complex with phenylfluorone. Germanium was separated from alkali and alkaline earths, manganese, iron, cobalt, nickel, copper, and zinc in binary mixtures by the exploitation of difference in pH for formation of citrato complexes. It was separated from antimony, bismuth, tin, gallium, indium, and thallium by taking advantage of stability of chloro and sulfato complexes. This method was applied to the determination of germanium in coal fly ash.
Synthesis of Urushiols with Pentadecatrienyl Side Chain, Two Constituents of the Sap of a Lac Tree, Rhus Vernicifera
Authors: Miyakoshi Tetsuo , Kobuchi Hidenori , Niimura Noriyasu , Yoshihiro Yoshiro 
Published: July 2006

Abstract
Two phenolic lipids, 3-[(8Z,11Z)-8,11,14- and 3-[(8Z,11E,13E)-8,11,13-pentadecatrienyl]catechol, which are the major constituents of the sap from a Japanese or Chinese lac tree, Rhus vernicifera, have been synthesized via the Wittig reaction of ylides derived from 3,6- and 3,5-heptadienylphosphonium salts with 3-(8-oxooctyl)catechol diacetate.
Stepwise Reduction of Acetals to the Corresponding Hydrocarbons. A Mild and Effective Transformation via Carbinyl Bromides
Authors: Oriyama Takeshi , Ichimura Yuichi , Koga Gen 
Published: July 2006

Abstract
Stepwise reduction of two alkoxyl groups in acetal was effected by the action of triethylsilane along with acetyl bromide and SnBr2 and then of tributyltin hydride (or lithium aluminium hydride) providing methyl or methylene compounds in good yields under very mild conditions.
Triethylborane Induced Selective 1,4-Reduction of α,β-Unsaturated Carbonyl Compounds with Triphenyltin Hydride or Tributyltin Hydride
Authors: Nozaki Kyoko , Oshima Koichiro , Utimoto Kiitiro 
Published: July 2006

Abstract
Reduction of α,β-unsaturated ketones and esters with triphenyltin hydride or tributyltin hydride in the presence of triethylborane has been studied. Whereas the reaction of α,β-unsaturated ketones (R1CH=CHCOR2) with triphenyltin hydride provided the corresponding saturated ketones (R1CH2CH2COR2), treatment of α,β-unsaturated ester (PhCH=CHCOOMe or CH3CH=CHCOO–n-C6H13) afforded an adduct (PhCH2CH(SnPh3)COOMe or CH3CH(SnPh3)CH2COO–n-C6H13).
Substituent Effects in the Decomposition of t-Alkyl t-Butyl Peroxides
Authors: Matsuyama Kazuo , Higuchi Yoshiki 
Published: July 2006

Abstract
The decomposition rates and products of various t-alkyl t-butyl peroxides were examined in cumene at several temperatures. The decomposition of these peroxides took place homolytically, depending on the structure of the t-alkoxyl moieties (RC(CH3)2–O), and was retarded in the order: R=(CH3)3CCH2&gt;(CH3)2CH&gt;CH3CH2CH2&gt;PhCH2&gt;CH3CH2&gt;ClCH2&gt;CH3. The rate constants for the electron-donating alkyl substitutents at 150 °C are correlated very well to a Taft equation (logkd=−10.93 Σσ*−6.61 (correlation coefficient of 0.9501)), which is fairly different from the equation logkd=−10.131 Σσ*−3.422 for electorn-withdrawing polar substituents. From this correlation and a product analysis, the nature of the polar character at the transition state of the decomposition is discussed.