Characterization of a Carbon-Nitrogen Network Solid with NMR and High Field EPR

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• 作者：David Rovnyak ; Marc Baldus ; Boris A. Itin ; Marina Bennati ; Andrew Stevens ; and Robert G. Griffin
• 刊名：Journal of Physical Chemistry B
• 出版年：2000
• 出版时间：October 26, 2000
• 年：2000
• 卷：104
• 期：42
• 页码：9817 - 9822
• 全文大小：116K
• 年卷期：v.104,no.42(October 26, 2000)
• ISSN：1520-5207

文摘

Considerable attention has been focused on developing a synthetic route to a carbon-nitrogen material withmechanical and thermal properties comparable or superior to those of diamond. To date, no substance withthe desired C₃N₄ stoichiometry in a silicon-nitride crystal lattice has been reported. One of the principaldifficulties in the pursuit of ultrahard carbon-nitrogen (CN) solids is the characterization of amorphous CNsamples. We describe a solid-state NMR study of a paracyanogen-like solid utilizing ¹³C-¹⁵N adiabatic-passageHartmann-Hahn cross-polarization (APHH-CP) to perform dipolar filtering and show that this method iswell-suited for recoupling ¹³C-¹⁵N in network solids. In addition, high-frequency electron paramagneticresonance (EPR) indicates a density of electron spins of approximately 1 × 10¹⁷ e^-/cm³. We conclude bydiscussing how NMR and EPR data may be useful for optimizing CN-polymer samples as potential precursorsfor ultrahard carbon nitrogen solids.