E. Wasserman

Osaka City University, Ōsaka, Ōsaka, Japan

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Publications (67)570.74 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
    ChemInform 10/2010; 23(40). DOI:10.1002/chin.199240084
  • P. J. KRUSIC, E. WASSERMAN
    [Show abstract] [Hide abstract]
    ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
    ChemInform 07/2010; 22(29). DOI:10.1002/chin.199129130
  • [Show abstract] [Hide abstract]
    ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
    ChemInform 04/2010; 23(15). DOI:10.1002/chin.199215032
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    ABSTRACT: In high-spin chemistry, random-orientation fine-structure (FS) electron spin resonance (ESR) spectroscopy entertains advantages as the most facile and convenient method to identify high-spin systems, as frequently reported in the literature. Random-orientation ESR spectroscopy applicable to organic high-spin entities can date back to the Wasserman and co-workers' attempt on the first spin-quintet dicarbene, m-phenylenebis(phenylmethlene) (m-PBPM), in the 2-MTHF glass in 1963 and 1967, following their successful work on randomly oriented triplet-state ESR spectroscopy. The FS ESR spectrum of m-PBPM in the 2-MTHF glass, however, has never fully been analyzed due to a peculiar line-broadening appearing at many canonical peaks. Organic high-spin spectra from most quintet dinitrenes also suffer from similar phenomena. Seemingly intrinsic line-diffusing or -broadening phenomena adversely affect the reliable determination of FS parameters for organic high-spin entities in rigid glasses. In high-spin chemistry, the line-broadening has been an obstacle that masks key FS transitions in many cases. Thus, both the origin of the broadening and the comprehensive spectral analysis have been a long-standing issue. In this report, we examine the origin of the line-broadening appearing in the FS ESR spectra, illustrated by a comprehensive spectral analysis for m-PBPM in the quintet ground state and the first-documented quintet-state dinitrene, m-phenylenebis(nitrene) (m-PBN) in the 2-MTHF glass. A complete analysis of the random-orientation FS spectra from m-PBPM diluted in the benzophenone crystal has shown that the g-anisotropy of m-PBPM is not prominent. Also the higher-order FS terms such as S(i)(2)S(j)(2) group-theoretically allowed for S = 2 are not necessary in spite of the argument for a hydrocarbon-based tetraradical (S = 2) in the ground state. Our new approach to the line-broadening analysis invokes both exact analytical solutions for the resonance fields of canonical peaks and the magnetic-parameters gradient method. The D- and E-values of m-PBPM acquired by the spectral simulation in this study give different molecular structures of the quintet dicarbene in the benzophenone crystal lattice (D = +0.0703(0) cm(-1), E = +0.0212(0) cm(-1)) and in the 2-MTHF glass (D = +0.0780(0) cm(-1), E = +0.0221(0) cm(-1)). Microscopic origins of the line-broadening observed for high-spin oligocarbenes or oligonitrenes generated by photolysis in organic glasses have been proposed.
    The Journal of Physical Chemistry A 09/2009; 113(34):9521-6. DOI:10.1021/jp9042717 · 2.78 Impact Factor
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    ABSTRACT: In high-spin chemistry, random-orientation fine-structure electron paramagnetic resonance (FS ESR) spectroscopy holds the advantages of the most facile and convenient method to identify high-spin systems. The FS ESR spectroscopy for high spins in frozen rigid glasses has seemingly been well established since the first spin-quintet m-dicarbene and m-dinitrene appeared in 1967. The FS ESR spectra of organic quintet entities generated by photolysis in the 2-methyltetrahydrofuran (2-MTHF) glass, however, have never been fully analyzed due to a peculiar line broadening appearing at many canonical peaks. The line broadening has been a notorious obstacle that masks key FS transitions of many cases in organic glasses or argon matrices. We examine the origin of the line broadening, illustrating the comprehensive spectral analysis for m-dinitrenes and other types of typical quintet-state dinitrenes observed in the 2-MTHF glass. Our new approach to the line broadening analysis invokes both exact analytical solutions for the resonance fields of canonical peaks and a magnetic-parameter gradient method. We have derived the exact analytical expressions for FS canonical peaks for high-spin states, for the first time. A microscopic origin of the line broadening observed for high-spin nitrenes generated by photolysis in rigid glasses is proposed on the basis of quantum chemical calculations of the D-tensor.
    Applied Magnetic Resonance 01/2009; 37(1):703-736. DOI:10.1007/s00723-009-0056-9 · 1.15 Impact Factor
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    ABSTRACT: Perfluoroalkylated nanospheres have been prepared by reaction of fullerenes with a variety of fluoroalkyl radicals. The latter are generated by thermal or photochemical decomposition of fluoroalkyl iodides or fluorodiacyl peroxides. Up to 16 radicals add to C(60) to afford easily isolable fluoroalkylated derivatives. The monosubstituted radical adducts were detected by electron spin resonance in the early stages of the fluoroalkylation reactions. These spheroidal molecules are thermally quite stable, soluble in fluoroorganic solvents, chemically resistant to corrosive aqueous solutions, and more volatile than the parent fullerenes. Films of the sublimed material display properties typical for a perfluoroalkylated material.
    Science 11/1993; 262(5132):404-7. DOI:10.1126/science.262.5132.404 · 31.48 Impact Factor
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    ABSTRACT: Continuous wave (CW) and time-resolved (TR) EPR spectra of triplet C[sub 60] with partial and full [sup 13]C enrichment in methylcyclohexane solutions after UV irradiation were obtained. Line broadening from [sup 13]C satellites was observed. The [sup 13]C hyperfine coupling constant was determined to be 0.06 G. Fourier transform EPR (FT-EPR) experiments with a resolution of 20 ns were carried out, and T[sub 1] was found to be 0.8 [+-] 0.1 [mu]s by fitting the intensity of the free induction decay signal to the modified Bloch equations. The relaxation time from FT-EPR is in excellent agreement with estimations from the line width of CW-EPR. Because the [sup 13]C hyperfine coupling constant is so small, no distinct satellite line were observed with [sup 13]C in natural abundance at 200 K. 32 refs., 4 figs.
    The Journal of Physical Chemistry 06/1993; 97(22):5886-5889. DOI:10.1021/j100124a018 · 2.78 Impact Factor
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    ABSTRACT: Conjugation in C60 is not as extensive as was originally anticipated because, for various reasons, the pentagon rings avoid containing double bonds. As a consequence, there is extensive bond localization and the molecule, which is quite reactive, and displays superalkene rather than superaromatic properties. C70 behaves in a similar fashion; other fullerenes may follow suit. Additions predominate and C60 is particularly susceptible to nucleophilic attack. Added groups may also be readily replaced by nucleophiles, although the reaction mechanism is uncertain at present. The functionalized molecule tends to revert to the parent fullerene at moderate temperatures, and characterization of reaction products by mass spectrometry is thus particularly difficult. This fact, coupled with the complexity of the addition products, makes work with fullerenes exacting. A selection of reactions studied to date and the progress made towards identifying various patterns of addition are described.
    Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences 04/1993; 343(1667):87-99. DOI:10.1098/rsta.1993.0043 · 2.86 Impact Factor
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    ABSTRACT: The early prediction of hollow graphite molecules suggested that they should be supercritical under ambient conditions. This is not true of C<sub>60</sub>, but might still be true of higher fullerenes and graphite nanotubes of large diameter.
    Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences 04/1993; 343(1667):9-18. DOI:10.1098/rsta.1993.0036 · 2.86 Impact Factor
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    ABSTRACT: Within the neighbourhood of the Sun, a number of highly evolved stars are carbonrich in the sense that they have more carbon than oxygen so their outer atmospheres contain molecules such as CN, CH and C2H2. These stars are cool with atmospheric temperatures near 3000 K and they are also luminous, typically 104 times more powerful than the Sun. The outer envelopes of these stars are tenuously bound, and they all are losing mass at a very high rate, in some cases more than [Note: See the image of page 63 for this formatted text] 10-5 MO a-1 (where MO denotes the mass of the Sun). These high luminosity carbon stars remain in this phase for a time, very approximately, near 105 years. They exhibit a large amount of carbon in their atmospheres because the products of the nuclear burning that occurs in the very centre of the star, including the synthesis of carbon, appear on the surface. In the extended envelopes around these stars, there is a very active chemistry, and the gas is sufficiently cool that nucleation of solid dust grains occurs. These solid particles may grow to sizes as large as 1 mu m although a more typical size is near 0.05 mu m. We therefore can identify both relatively small carbon-bearing molecules (for example HC7N) and much larger carbon-containing dust grains in the outflows. The amount of intermediate size particles or molecules, such as C60, and their possible role in the circumstellar chemistry is not yet well understood. At least in the envelope of the well studied carbon star IRC + 10216, there appears to be more carbon in CO and solid grains than in polycyclic aromatic hydrocarbons.
    Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences 04/1993; 343(1667):63-71. DOI:10.1098/rsta.1993.0041 · 2.86 Impact Factor
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    ABSTRACT: By chance in 1970, we conjectured the possibility of the football-shaped C60 molecule, now known as buckminsterfullerene, while considering superaromatic molecules having three-dimensional pi -electron delocalization. A translation of the original description, initially written in Japanese, is given. The processes leading to scientific discoveries are analysed in the light of our missed opportunity.
    Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences 04/1993; 343(1667):1-8. DOI:10.1098/rsta.1993.0035 · 2.86 Impact Factor
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    ABSTRACT: Conjugation in C<sub>60</sub> is not as extensive as was originally anticipated because, for various reasons, the pentagon rings avoid containing double bonds. As a consequence, there is extensive bond localization and the molecule, which is quite reactive, and displays superalkene rather than superaromatic properties. C<sub>70</sub> behaves in a similar fashion; other fullerenes may follow suit. Additions predominate and C<sub>60</sub> is particularly susceptible to nucleophilic attack. Added groups may also be readily replaced by nucleophiles, although the reaction mechanism is uncertain at present. The functionalized molecule tends to revert to the parent fullerene at moderate temperatures, and characterization of reaction products by mass spectrometry is thus particularly difficult. This fact, coupled with the complexity of the addition products, makes work with fullerenes exacting. A selection of reactions studied to date and the progress made towards identifying various patterns of addition are described.
    Philosophical transactions. Physical sciences and engineering 01/1993; 343(1667):87-101. DOI:10.2307/54137
  • [Show abstract] [Hide abstract]
    ABSTRACT: By chance in 1970, we conjectured the possibility of the football-shaped C<sub>60</sub> molecule, now known as buckminsterfullerene, while considering superaromatic molecules having three-dimensional π -electron delocalization. A translation of the original description, initially written in Japanese, is given. The processes leading to scientific discoveries are analysed in the light of our missed opportunity.
    Philosophical Transactions of The Royal Society B Biological Sciences 01/1993; 343. DOI:10.2307/54129 · 6.31 Impact Factor
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    ABSTRACT: Within the neighbourhood of the Sun, a number of highly evolved stars are carbonrich in the sense that they have more carbon than oxygen so their outer atmospheres contain molecules such as CN, CH and C<sub>2</sub>H<sub>2</sub>. These stars are cool with atmospheric temperatures near 3000 K and they are also luminous, typically 10<sup>4</sup> times more powerful than the Sun. The outer envelopes of these stars are tenuously bound, and they all are losing mass at a very high rate, in some cases more than [Note: See the image of page 63 for this formatted text] 10<sup>-5</sup> M<sub>O</sub> a<sup>-1</sup> (where M<sub>O</sub> denotes the mass of the Sun). These high luminosity carbon stars remain in this phase for a time, very approximately, near 10<sup>5</sup> years. They exhibit a large amount of carbon in their atmospheres because the products of the nuclear burning that occurs in the very centre of the star, including the synthesis of carbon, appear on the surface. In the extended envelopes around these stars, there is a very active chemistry, and the gas is sufficiently cool that nucleation of solid dust grains occurs. These solid particles may grow to sizes as large as 1 μ m although a more typical size is near 0.05 μ m. We therefore can identify both relatively small carbon-bearing molecules (for example HC<sub>7</sub>N) and much larger carbon-containing dust grains in the outflows. The amount of intermediate size particles or molecules, such as C<sub>60</sub>, and their possible role in the circumstellar chemistry is not yet well understood. At least in the envelope of the well studied carbon star IRC + 10216, there appears to be more carbon in CO and solid grains than in polycyclic aromatic hydrocarbons.
    Philosophical transactions. Physical sciences and engineering 01/1993; 343(1667):63-72. DOI:10.2307/54135
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    ABSTRACT: Alkyl radicals generated in solution by UV photolysis add to C60 to form adducts of the type RC60, whose EPR spectra are discussed. When R = CCl3, CBr3, tert-butyl or 1-adamantyl, the spectrum is sufficiently powerful to permit the detection of several 13C satellites associated with the C60 component of the free radical. It is concluded from the intensities and hyperfine interactions of these satellites that ca. 2/3 of the unpaired spin population is located on the three carbon atoms ortho to that bearing the incoming radical R.
    Journal of the Chemical Society Perkin Transactions 2 09/1992; DOI:10.1039/p29920001425
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    ABSTRACT: UV irradiation of methylcyclohexane solutions of C60 produces a very narrow, transient EPR absorption which is assigned to the first excited triplet state of C60. The line width of only 0. 14 G, uncommon for motionally narrowed triplet EPR spectra, is attributed to a very rapid interchange of the magnetic axes by pseudorotation converting the degenerate Jahn-Teller states into each other. Time-resolved, direct-absorption EPR measurements with a time resolution of 0.5-mu-s support this conclusion. They indicate that in solution the triplet EPR absorption decays at rates comparable with those obtained by optical methods for C-3(60). A relaxation time T1 of 8-mu-s was obtained from the oscillations observed in the early stages of the decay curve following laser excitation. This T1, and the line width in solution, require correlation times between 10(-12) and 10(-13) s, too short for rotation. Polarized, partially averaged powder triplet spectra were also observed in methylcyclohexane glasses at low temperatures. The pseudorotation proposal is supported by the distinctly different behavior of C70.
    The Journal of Physical Chemistry 06/1992; 96(13). DOI:10.1021/j100192a011 · 2.78 Impact Factor
  • Journal of the American Chemical Society 06/1992; 114(13). DOI:10.1021/ja00039a083 · 11.44 Impact Factor
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    ABSTRACT: C60 and liquid bromine react to form C60Br24, a crystalline compound isolated as a bromine solvate, C60Br24(Br2)x, The x-ray crystal structure defines a new pattern of addition to the carbon skeleton that imparts a rare high symmetry. The parent C60 framework is recognizable in C60Br24, but sp3 carbons at sites of bromination distort the surface, affecting conformations of all of the hexagonal and pentagonal rings. Twenty-four bromine atoms envelop the carbon core, shielding the 18 remaining double bonds from addition. At 150° to 200°C there is effectively quantitative reversion of C60Br24 to C60 and Br2.
    Science 05/1992; 256(5058):822-825. DOI:10.1126/science.256.5058.822 · 31.48 Impact Factor
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    ABSTRACT: Photolytically and thermally generated alkyl radicals (R. = tert-butyl, 1-adamantyl, isopropyl, ethyl, and benzyl) react with C60 to form R-C60. radical adducts which have been identified by the proton and C-13 hyperfine interactions obtained from their electron spin resonance spectra. Consideration of the C-13 spectra shows that the unpaired electron in R-C60. is mostly confined to two fused, six-membered rings on the C60 surface, having the substituent R at one of the points of fusion. Each half of the resulting radical structure of C(s) symmetry can be compared with a cyclohexadienyl radical. Extensive delocalization of the unpaired electron over the C60 sphere is ruled out.
    The Journal of Physical Chemistry 04/1992; 96(9). DOI:10.1021/j100188a006 · 2.78 Impact Factor
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    ABSTRACT: The metalation, halogenation and free radical addition chemistry of C60 is described. Vibrational spectroscopy is a useful tool in assigning the structures of the products. Several underlying principles emerge for C60 chemistry, some of which are supported by molecular orbital calculations.
    ChemInform 01/1992; 30(8):1213-1226. DOI:10.1016/0008-6223(92)90063-3

Publication Stats

3k Citations
570.74 Total Impact Points

Institutions

  • 2009
    • Osaka City University
      • Graduate School of Science
      Ōsaka, Ōsaka, Japan
  • 1993
    • Toyohashi University of Technology
      • Department of Knowledge-based Information Engineering
      Toyohasi, Aichi, Japan
    • University of Sussex
      • Department of Chemistry
      Brighton, England, United Kingdom
  • 1991–1993
    • Dupont
      • Central Research and Development
      Delaware, Ohio, United States
  • 1976
    • Rutgers, The State University of New Jersey
      New Brunswick, New Jersey, United States
    • Brooklyn Research
      New York, New York, United States
  • 1967
    • Columbia University
      • Department of Chemistry
      New York, New York, United States