bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phosphinidenes and Related Intermediates. III. Reactions of Phosphinylidenes and Phosphinothioylidenes with Conjugated Dienes
Authors: Nakayama Shigenobu , Yoshifuji Masaaki , Okazaki Renji , Inamoto Naoki 
Published: July 2006

Abstract
Phenylphosphonic and phenylphosphonothioic dichlorides were dechlorinated with magnesium to generate phenylphosphinylidene and phenylphosphinothioylidene, respectively, in the presence of several 1,3-dienes. Reactions of phenylphosphinothioylidene with 2,3-dimethylbutadiene and 1,3-cyclohexadiene gave Diels-Alder type reaction products, that is, 3,6-dihydro-1,2-thiaphosphorin derivatives (5 and 6) and 6-phenyl-5,6-thiaphosphabicyclo[2.2.2]oct-2-ene 6-sulfide (14), respectively. Reaction of 2,3-diphenylbutadiene with phenylphosphinothioylidene afforded 1,2,4,5-tetraphenyl-1,2,3,6-tetrahydro-1,2-diphosphorin 1,2-disulfide (10), whereas that with phenylphosphinylidene gave 1,3,4-triphenyl-3-phospholene 1-oxide (12). The differences of these reactions have been discussed.
The Photolysis of 3,4-Bis(hydroxydiphenylmethyl)cyclobut-3-ene-1,2-dione and Related Compounds. The Formation of a New Bislactone, 4,4,8,8-Tetraphenyl-3,7-dioxabicyclo[3.3.0]oct-1(5)-ene-2,6-dione
Authors: Toda Fumio , Todo Eishiro 
Published: July 2006

Abstract
The photolysis of 3,4-bis(hydroxydiphenylmethyl)cyclobut-3-ene-1,2-dione (1) in benzene afforded 4,4,8,8-tetraphenyl-3,7-dioxabicyclo[3.3.0]octane-2,6-dione (3) in an 80% yield. The photolysis of 1 in MeOH afforded 4,4,8,8-tetraphenyl-3,7-dioxabicyclo[3.3.0]oct-1(5)-ene-2,6-dione (4), 4-methoxycarbonyl-3,3-diphenyl-5-diphenylmethylene-2-oxacyclopentan-1-one (5), and 4-carboxy-3,3-diphenyl-5-diphenylmethyl-2-oxacyclopent-4-en-1-one (6), in 3, 8, and 22% yields respectively. The mechanisms of the formation of the 5 and 6 are discussed. The photolysis of 3-hydroxydiphenylmethyl-4-diphenylmethoxymethylcyclobut-3-ene-1,2-dione (14) and 3,4-bis(diphenylmethyl)cyclobut-3-ene-1,2-dione (18) was also investigated.
The Reactions of β-Amino α,β-Unsaturated Esters with Amines. II. Syntheses of Some New Derivatives of Quinazolines
Authors: Yokoyama Yasukazu , Shibata Katsuya , Fujii Osamu , Iwamoto Eiji 
Published: July 2006

Abstract
The reaction of 1,4-bis(ethoxycarbonyl)-2,5-diamino-1,4-cyclohexadiene(Ia) with aniline in aprotic solvents gave N,N′-diphenylurea, whereas in the presence of a proton acid this reaction gave an amine-exchanged product,14-bis(ethoxycarbonyl)-2,5-dianilino-1,4-cyclohexadiene(Ib). However, when 2-aminopyridine was used in place of aniline for this reaction, 1,4-bis(ethoxycarbonyl)-2,5-bis(2-pyridylamino)-1,4-cyclohexadiene(Ic) was not isolated but its cyclyzed analogue, 6,7,14,15-tetrahydropyrido[2,1-b]pyrido[1′,2′:1,2]pyrimido[4,5-g]quinazoline-7,15-dione(IIa), was obtained. The reaction of 2-amino-6-methylpyridine with la also gave a quinazoline derivative without producing a 1,8-naphthyridine derivative. Since this reaction took place easily in a weak acid, AcOH, this cyclization could proceed by an intramolecular proton-transfer mechanism.
The Extraction of Alkali Metal Picrates with Dibenzo-18-Crown-6
Authors: Sadakane Akira , Iwachido Tadashi , Tôei Kyoji 
Published: July 2006

Abstract
The distribution of alkali metal picrate complexes of macrocyclic polyether (dibenzo-18-crown-6) between water and benzene was investigated. The polyether-cation complexes were found to be of a 1:1 stoichiometry. The formation of 2:1 complexes was recognized for Rb and Cs in a large excess of the poiyether. The extractability of complex cation-picrate ion-pairs decreases in this sequence: K&gt;Rb&gt;Cs&gt;Na&gt;Li. The values of the extraction constants (logKex) were determined to be 4.65, 3.75, and 3.07 for K, Rb, and Cs compounds respectively. The thermodynamic quantities for the extraction process were calculated from the change in the extraction constants with the temperature. The extraction reactions are all exothermic, accompanied by an entropy decrease.
A New Synthesis of 3,6-Dialkyl-1,4-dimethyl-3,6-epithio-and -3,6-epidithio-2,5-piperazinediones
Authors: Yoshimura Juji , Nakamura Hiroshi , Matsunari Kenji 
Published: July 2006

Abstract
A new route for synthesis of 3,6-dialkyl-1,4-dimethyl-3,6-epithio- (8) and -3,6-epidithio-2,5-piperazinediones (9) via the corresponding bromo derivatives was described. Bromination of 3,6-dialkyl-1,4-dimethyl-2,5-piper-azinedione with N-bromosuccinimide gave 3,3α,6,6α-tetrabromo (2) and 3,6-dibromo (3) derivatives, depending upon the straight chain (methyl, ethyl, propyl, butyl) or α-branched (isopropyl, sec-butyl) alkyl groups, respectively. After tentative substitution of 3,6-bromine atoms of 2 with methanol, 3α,6α-bromine atoms were reduced to give the corresponding 3,6-dialkyl-3,6-dimethoxy derivatives (5). Substitution of 3 or 5 with hydrogen sulfide in the absence or presence of zinc chloride, and successive oxidation with potassium triiodide gave 8 and 9 at the same time. Discussions were made on the structure of isomers and on the reaction mechanisms.
Aminosugars. XXIII. l-Idofuranose Derivatives Containing a Heterocycle at C-5,6 Position
Authors: Iwakawa Masaharu , Yoshimura Juji 
Published: July 2006

Abstract
2-Aryl-(5S)- and -(4S)-(3′-O-benzyl- and 3′-O-methyl-1′,2′-O-isopropylklene-α-d-xylo-tetrofuranos-4′-yl)-2-oxazolines (3 and 7) were prepared from 6-aroylamido-6-deoxy-5-O-tosyl-d-glucofuranose and 5,6-aroylepimino-5,6-dideoxy-l-idofuranose derivatives, respectively. The corresponding 2-thioxo-(4R)- and -(5S)-thiazolidine derivatives (11 and 13) were also synthesized from 5,6-dideoxy-5,6-epimino-l-idofuranose and 6-azido-6-deoxy 5-O-tosyl-d-glucofuranose derivatives, respectively. 2-S-Methylated derivatives of 11 and 13 were reduced with aluminum amalgam to give the corresponding (4R)- and (5S)-thiazolidine derivatives, respectively. Formation of an intramolecular hemiaminal ring in 11 gave a new type of bicyclic derivatives; (5S,6R,8R)-triacetoxy-(7S)-substituted-2-thioxo-(8aR)-perhydropyrido[1,2-c]thiazole (16a and 16b). The structure of new compounds was examined by NMR spectroscopy.
ESR Spectra of Monoprotonated Semiquinone Radicals Formed during Photolysis of p-Benzoquinone and Its Methyl Derivatives
Authors: Warashina Tetsuo , Edlund Ove , Yoshida Hiroshi 
Published: July 2006

Abstract
Proton hyperfine coupling constants of monoprotonated p-benzosemiquinone, durosemiquinone, 2,6-dimethyl-p-benzosemiquinone, 2,5-dimethyl-p-benzosemiquinone and methyl-p-benzosemiquinone radicals were determined from ESR spectra during photolysis of the corresponding quinones under identical conditions, i.e., in ethanol and at about 20 °C. By considering all these constants together, the ESR spectra were assigned and following results obtained: (1) the hydroxyl groups were at the oxygen atom further from the methyl substituents, (2) the coupling constant was generally −1.86–−1.65 G for the hydroxylic protons, (3) the absolute value of the coupling constant for both ring and methyl protons was in the range 0–0.7 G for ortho-positions and 4.3–5.2 G for meta-positions relative to the hydroxyl group, and (4) the hydroxylic proton of durosemiquinone had an exceptionally small coupling constant because of steric hindrance of the methyl groups. The temperature dependence of the coupling constants in p-benzosemiquinone revealed an asymmetry of the meta-ring protons at low temperature due to the hindrance of hydroxyl group rotation. The coupling constants for p-benzosemi-quinone were calculated with the INDO method. However, the results were not satisfactory because the calculated coupling constant was too large for the ortho-protons and the asymmetry calculated for the conformation with the hydroxylic proton fixed at one of the stationary sites was too small to interpret the observations.
Binuclear Metal Complexes. X. Preparation and Magnetism of Mononuclear and Binuclear Copper(II) Complexes of Schiff Bases Derived from 4,6-Diacetylresorcine and Polyamines
Authors: Manada Noriaki , Okawa Hisashi , Kida Sigeo 
Published: July 2006

Abstract
New binuclear complexes Cu2X2dar(en-R)2 and [Cu2dar(dien)2](ClO4)2·H2O were synthesized, H2dar(A)2being a Schiff base prepared from 4,6-diacetylresorcinol and an amine A;A stands for N,N-dialkylethylenediamine-(=en-R, R=C2H5 or iso-C3H7) or diethylenetriamine(=dien). Mononuclear complexes CuXHdar(en-R) were also prepared for comparison. Two copper(II) ions of the binuclear complexes are separated from each other by the benzene ring. Magnetic susceptibilities of the compounds were measured in the temperature range 77.4∼300 K. It was found by means of the plots of χA−1 versus T that all the compounds obey the Curie-Weiss law. The Weiss constants for the binuclear complexes (−10∼−34 K) indicate the presence of antiferromagnetic interactions between copper(II) ions through the conjugated π-system of 4,6-diacetylresorcinol moiety, whereas those of the mononuclear complexes are practically zero, showing that the intermolecular interaction is negligibly small.
Physico-chemical Properties of Selenium-Tellurium-Sulfur Crystals
Authors: Nakagawa Toshio 
Published: July 2006

Abstract
The temperature dependence of electric conductivity and Vickers hardness of Selenium–Tellurium–Sulfur (Se–Te–S) crystals were studied. The conductivity decreased with an increase in sulfur content, remaining almost constant when the sulfur content was 40–80 atomic % at 20 and 30 atomic % of tellurium content. When tellurium content was 10%, both conductivity and hardness decreased abruptly when sulfur content exceeded 10%. It was found by means of X-ray diffraction that a hexagonal crystal structure with size twice the lattice constant of Se–Te crystals is formed when the sulfur content is 20% at 10% of tellurium content. When sulfur content exceeds 80%, the crystal structure becomes similar to that of pure sulfur (orthorhombic) at 20 and 30% of tellurium.
Emission Spectra of Dimethoxybenzenes by Controlled Electron Impact
Authors: Ogawa Teiichiro , Imasaka Totaro , Toyoda Minoru , Tsuji Masaharu , Ishibashi Nobuhiko 
Published: July 2006

Abstract
The emission spectra of o-, m-, and p-dimethoxybenzenes under controlled electron impact excitation (200 eV) were measured in the 220–450 nm region at very low pressures. The photoemissions of the excited parent species and such fragment species as H, CH, CO, and CO+ were observed and assigned. The relative intensities of the photoemissions of the parent species were compared with those of the fluorescence spectra (photoexcitation) in an n-hexane solution. The excited parent species, H, and CH were concluded to be produced in one-electron processes; however, the CO+ species were assumed to be produced in both one- and two-electron processes, and the relative contributions are evaluated. It was concluded that the rate of the predissocation of o-dimethoxybenzene was faster than those of the other two isomers, and the observed characteristics of o-dimethoxybenzene had something to do with this faster rate.
Ultrasonic Absorption Mechanism in an Aqueous Solution of n-Propyl Alcohol
Authors: Nishikawa Sadakatsu , Mashima Mitsuo , Yasunaga Tatsuya 
Published: July 2006

Abstract
Ultrasonic absorption in aqueous solutions of n-propyl alcohol was measured in the frequency range of 4.5–220 MHz and in the concentration range of 2.0–13.4 M at 25 °C. Two different relaxation processes were observed; they were attributed to the perturbation of the equilibria expressed by (Remark: Graphics omitted.) where A and B are a single water molecule and an alcohol molecule respectively. The forward and backward rate constants for the two processes were determined from the concentration dependences of the relaxation frequencies. Furthermore, the influence of n-propyl alcohol on the water structure was discussed; the addition of n-propyl alcohol to liquid water was concluded to promote the water structure.
14N Nuclear Quadrupole Resonances of Sulfuric Diamide and Its Derivatives
Authors: Negita Hisao , Kubo Tsuneo , Shibata Kaoru 
Published: July 2006

Abstract
The study of 14N nuclear quadrupole resonance (NQR) was performed on sulfuric diamide (sulfamide) and its methyl derivatives, such as N,N-dimethylsulfamide and tetramethylsulfamide. The 14N NQR parameters for sulfuric diamide and tetramethylsulfamide were (|e2Qq|=3905.3 kHz; η=0.5082) and (|e2Qq|=5325.9 kHz; η=0.1768) respectively. In the case of N,N-dimethylsulfamide, the parameters were (|e2Qq|=4022.9 kHz; η=0.4799) for the nitrogen atoms of NH2 groups and (|e2Qq|=5125.0 kHz; η=0.2024) for the nitrogen atoms of N(CH3)2 groups. From the temperature dependence of the resonance lines due to nitrogen atoms in sulfuric diamide, tetramethylsulfamide, and the NH2 group of N,N-dimethylsulfamide, it is considered that the hydrogen bonds in sulfuric diamide are stronger than those in N,N-dimethylsulfamide. On the other hand, the electron densities for the N–S bond in sulfuric diamide and its methyl derivatives were derived from the corresponding NQR parameters.
Nuclear Quadrupole Resonances of 2,4,6-Trichlorobenzonitrile
Authors: Negita Hisao , Shibata Kaoru , Kubo Tsuneo 
Published: July 2006

Abstract
2,4,6-Trichlorobenzonitrile was examined by means of the nuclear quadrupole resonances (NQR) resulting from 14N and 35Cl nuclei. One 14N resonance line (the higher line of the pair) and three 35Cl resonance lines were observed. The Zeeman effect on a single crystal was studied in an attempt to predict the lower 14N line. Thus, |e2Qq|=3936.7 kHz and η=0.1298 were calculated for the nitrogen atom; the frequency of the lower line was estimated at 2824.8 kHz. On the other hand, (η=0.130; |e2Qq|=71.209 MHz), (0.128; 72.594), and (0.116; 73.720) were determined for the chlorine atoms in the order of increasing frequencies by studying the Zeeman effect of 35Cl NQR on the single crystal.
Polarographic Studies of Bis(2,2′,2″-terpyridine) Complexes of Manganese(II), Cobalt(II), Nickel(II) and Europium(III) in Acetonitrile
Authors: Aihara Makoto , Kishita Hirofumi , Misumi Seizo 
Published: July 2006

Abstract
The reduction mechanism of bis 2,2′,2″-terpyridine complexes of manganese(II), cobalt(II), nickel(II) and europium (III) were investigated in acetonitrile by means of DC and AC polarograph and Kalousek polarograph at DME and cyclic voltammetry at an HDME. It was found that univalent metal complex anions, such as [M-(terpy)2]− (M=manganese and nickel), were formed at the electrode surface in acetonitrile. For the europium(III) complex, the standard rate constant of the second reduction step was estimated.
Isomerization of Heptanes over a Palladium–Zeolite Catalyst
Authors: Sakai Tomoya , Goto Masafumi , Hatano Kei-ichiro , Kato Manjiro 
Published: July 2006

Abstract
The isomerization of heptane isomers, heptane, 2- and 3-methylhexane, 3-ethylpentane, and 2,3- and 2,4-dimethylpentane, was investigated kinetically over a palladium-zeolite catalyst in the presence of hydrogen at 280–350 °C. First-order rate constants of 11 reaction paths were given with their activation energies and pre-exponential factors. The reaction scheme network including 22 isomerization steps among 9 isomers was constructed through the detailed analysis of primary and secondary reaction products from the individual isomers. Finally, the several proposed isomerization mechanisms were examined on the basis of the present experimental results.
Estimation of Structures and Electronic States of Radicals Using INDO-SCFMO Method. II. Alkylperoxyl Radicals
Authors: Ohkubo Katsutoshi , Kitagawa Futoshi 
Published: July 2006

Abstract
The energetically most stable CH3OO and CH3CH2OO radicals have been found to have the following geometric values: r(Oα–Oβ)=1.12 Å, r(Oα–C)=1.38 Å for the former and 1.39 Å for the latter, ∠COαOβ=112° for the former and 115° for the latter, and r(C–C)=1.47 Å for the latter.
Substitution Reaction of Ethylenediaminetetraacetatoaluminate(III) with Indium(III) in Aqueous Solutions
Authors: Tsuchimoto Michiko 
Published: July 2006

Abstract
The kinetics of substitution reaction between the aluminium(III) EDTA complex and the indium(III) ion has been studied in aqueous solutions of pH 2–10; the aluminium(III) complex is more labile than the gallium(III) and the indium(III) complex.
The Synthesis of 24-Norfriedel-4-en-3-one
Authors: Kakisawa Hiroshi , Horie Tsuneyuki , Kusumi Takenori 
Published: July 2006

Abstract
The lead tetraacetate oxidation of 24-hydroxyfriedel-3-ene, prepared from friedelin, afforded a 3-acetoxy-24-norfriedel-4-ene, which was then convered into the title compound.
On the Mechanism of the Diels-Alder Reaction between 1,3-Cyclopentadiene and 1,3-Cyclohexadiene
Authors: Maeda Terunobu , Hamanaka Sawako , Ogawa Masaya 
Published: July 2006

Abstract
The reaction of 1,3-cyclopentadiene with 1,3-cyclohexadiene, when carried out at 94–118 °C for 5–7 hr, gave tricyclo[4.4.0.12,5]undeca-3,7-diene rather than tricyclo[5.2.2.02,6]undeca-3,8-diene.
Molecular Vibrations and Force Fields of Alkyl Sulfides. X. Skeletal Bending Vibrations of Several Simple Aliphatic Sulfides
Authors: Ohsaku Masaru 
Published: July 2006

Abstract
The skeletal bending vibrations of several normal alkyl sulfides were analysed. It is found that a heterogeneous system as this case can also be explained in the same manner as a homogeneous system.
Preparation of Tetramethylphthalimide
Authors: Chiba Koji , Endo Eiji , Yamaka Kyoji 
Published: July 2006

Abstract
Treatment of tetramethylphthalic anhydride (I) with 28% aqueous ammonia at room temperature afforded ammonium tetramethylphthalimide (IV) and and 2-cyano-3,4,5,6-tetramethylbenzoate (V). The amount of IV increased by heating at 100 °C, tetramethylphthalimide (VI) being precipitated. A plausible reaction path is proposed.
Molecular Structure of 7-Oxanorbornane as Studied by Gas Electron Diffraction
Authors: Oyanagi Kazuko , Fukuyama Tsutomu , Kuchitsu Kozo , Bohn Robert K , Li Shu-tung 
Published: July 2006

Abstract
The structure of 7-oxabicyclo[2.2.1]heptane (7-oxanorbornane) in the gas phase has been investigated by making joint use of the electron diffraction intensities measured in the present study and the rotational constants reported by Creswell. The thermal average bond lengths are: rg(C1–C2)=1.533±0.014 Å, rg(C2–C3)=1.571±0.015 Å, rg(C–O)=1.442±0.010 Å, and rg(C–H)=1.117±0.008 Å. The bond angles in the zero-point average structure (rav) are: ∠C–O–C=94.5±2.2°, θ (the dihedral angle between the C1–C2–C3–C4 and C4–C5–C–6–C1 planes)=113.5±0.8° and ∠H–C–H=105±5°. The uncertainties represent the estimated limits of experimental error. The C2–C3 bond is longer than the C1–C2 bond, and the latter distance is nearly equal to that of a normal C–C single bond. The C–O bond is about 0.02 Å longer, and the C–O–C bond angle is about 17° smaller than the corresponding parameters in dimethyl ether. These trends are analogous to those observed for norbornane and 7-thianorbornane.
An MO-theoretical Approach to the Aquation Mechanism of Carboxylatopentaammineruthenium(III) Complexes in Acid Solutions
Authors: Ohkubo Kastutoshi , Kitagawa Futoshi , Sakamoto Hiroyuki , Ohyoshi Akira 
Published: July 2006

Abstract
The aquation mechanism of carboxylatopentaammineruthenium(III) complexes, (NH3)5RuO2CR2+, where R=H, CH3, C2H5, (CH3)2CH, and CH2OH, has been investigated with the Wolfsberg-Helmholz-LCAO-MO extended Hückel method augmented by metal d-orbitals. The very weak Ru–O coordination linkage (bond population=0.085–0.092) formed mainly by the antibonding dz2pz-σ and pzpz-σ orbitals facilitates the heterolytic bond-breaking of the Ru–O(dissociation energy=4.61–9.22 kcal/mol), and the order of the bond populations of the Ru–O is well reflected in that of the overall aquation rates.The preferable structure of the protonated complex is (NH3)5RuOHG(=O)R2+, produced by the interaction between the H+ catalyst and the non-bonding lonepair orbital of the neighboring oxygen atom attached to the metal.The H2O solvent was found to play an important role in the bond dissociation of the metal-oxygen linkage from a linear dependence between the reactivity index (1/2Nz2LU) of the protonated complex to such nucleophiles as H2O and the activation energy for the SN2 aquation reaction. The proposed tetragonal pyramidal intermediate of (NH3)5Ru3+ combines easily the Ru–O through the lowest unoccupied dz2 Ru-orbital, forming an aquo-complex with the binding energy of with H2O linkage, 30.25 kcal/mol
Apparent Molal Volumes and Adiabatic Compressibilities of n-Alkanols and α,ω-Alkane Diols in Dilute Aqueous Solutions at 5, 25, and 45°C. I. Apparent Molal Volumes
Authors: Nakajima Toshio , Komatsu Tsuyoshi , Nakagawa Tsurutaro 
Published: July 2006

Abstract
Density measurements have been carried out on a series of dilute aqueous solutions of n-alkanols and α,ω-alkane diols. The apparent molal volumes, φV, have been derived, and the φ°V values (V°2) at an infinite dilution have been estimated. The \barV°2, the ∂2\barV°2⁄∂T, and the ∂2\barV°2⁄∂T2 of the CH2, the CH3, and the CH2OH groups were obtained from the dependence of the \barV°2 and its temperature behavior upon the alkyl-chain length. It was found that the ∂2\barV°2⁄∂T2 value well reflects the structural effect.
Photochromism of 2-Hydroxytriphenylmethanol and Its Derivatives
Authors: Hamai Sanyo , Kokubun Hiroshi 
Published: July 2006

Abstract
2-Hydroxytriphenylmethanol (HM) shows photochromism in air-saturated acetonitrile and other solvents and also in the crystalline state. The colored form has been deduced to be o-fuchsone, produced by photochemical dehydration of HM. The photochromism mechanism is entirely different from that of other triarylmethane derivatives. The colored form is the same species as in thermochromism. The reactive state of HM was found to be the excited singlet state from the results of quenching experiments. The quantum yield of the photochemical reaction was determined to be 0.62 in acetonitrile by a method based on the equilibrium between the photochemical and thermal bleaching reactions. Photochromism occurs also at 77 K. At this temperature, HM radical is produced beside the colored form. The ratio of the concentration of HM radical to the colored form increases with irradiation time. Several HM derivatives show photochromism similar to HM.
The Syntheses of Ripariochromene A and Methylripariochromene A
Authors: Tsukayama Masao 
Published: July 2006

Abstract
7,8-Dimethoxy-2,2-dimethylchroman was obtained from pyrogallol trimethyl ether and β,β-dimethylacrylyl chloride via the corresponding chroman-4-one. The Friedel-Crafts reaction of the chroman with acetyl chloride yielded 6-acetyl-7-hydroxy-8-methoxy-2,2-dimethylchroman. The dehydrogenation of the acetylchroman with DDQ in anhydrous benzene afforded ripariochromene A. Ripariochromene A was converted into methylripariochromene A
The Magnetic Properties of Verdazyl Free Radicals. IX. The Crystal Structure of 1,3,5-Triphenyl-6-methylverdazyl Radical
Authors: Azuma Nagao , Deguchi Yasuo , Marumo Fumiyuki , Saito Yoshihiko 
Published: July 2006

Abstract
The crystal structure of 1,3,5-triphenyl-6-methylverdazyl has been determined by X-ray diffraction. The crystals are orthorhombic, with the space group of Pnma and with a=18.25(1), b=16.65(1), c=5.776(2) Å, and Z=4. The structure was deduced from the sharpened Patterson synthesis and was refined by the block-diagonal least-squares method to the final R value of 0.055 for 960 non-zero reflections collected on an automated four-circle diffractometer. The sym-tetrazinyl ring has an asymmetrical boat form, as has been observed in both 1,3,5-triphenylverdazyl and 1,3,5-tri-p-tolylverdazyl. The complete intermolecular overlap was observed in a tilted face-to-face array along the c-axis; this accounts for a fairly strong antiferromagnetic exchange interaction between the unpaired electrons.