@article{shultz_boal_lee_farmer_1999, title={Structure-property relationships in trimethylenemethane-type biradicals. 2. Synthesis and EPR spectral characterization of dinitroxide biradicals}, volume={64}, ISSN={["0022-3263"]}, DOI={10.1021/jo990061j}, abstractNote={Several trimethylenemethane-type (TMM-type) dinitroxide biradicals have been prepared that differ in tert-butylaminoxylphenyl ring torsion angles by virtue of different steric demands of their “spin-protecting groups”. In addition, the synthesis of a TMM-type dinitroxide having a planar π-system is reported. The synthetic route employed for the planar TMM-type biradical is general and should therefore expand the utility of TMM-type biradicals that are susceptible to bond torsions that attenuate exchange coupling. The compounds presented are designed to be effective to map out J-coupling/conformation space in TMM-type biradicals. EPR spectroscopic parameters (hfcc and D-values) were compared to determine if their values reflected differences in conformation in the series of biradicals. Interestingly, neither N- nor H-hfcc varied within our series of biradicals/monoradicals in a regular fashion, indicating that there is no apparent relationship between N- or H-hfcc and conformation (as judged by molecular m...}, number={12}, journal={JOURNAL OF ORGANIC CHEMISTRY}, author={Shultz, DA and Boal, AK and Lee, H and Farmer, GT}, year={1999}, month={Jun}, pages={4386–4396} }
 @article{shultz_farmer_1998, title={Synthesis and characterization of a nitroxide-semiquinone biradical}, volume={63}, ISSN={["0022-3263"]}, DOI={10.1021/jo980562p}, abstractNote={The synthesis and characterization of an anion biradical, 1(-)(*)(*), composed of semiquinone and nitroxide functionalities is described. The biradical was prepared by reduction of the nitroxide-orthoquinone precursor using both electrochemical and chemical methods. The zero-field-splitting parameter, |D/hc|, for 1(-)(*)(*) is consistent with the proposed electronic structure, based on a comparison to |D/hc| of related biradicals. Finally, the results of variable-temperature EPR spectroscopy are in agreement with ferromagnetic (high-spin) coupling of the two unpaired electrons through the m-phenylene group.}, number={18}, journal={JOURNAL OF ORGANIC CHEMISTRY}, author={Shultz, DA and Farmer, GT}, year={1998}, month={Sep}, pages={6254–6257} }
 @article{shultz_boal_farmer_1998, title={Synthesis of bis(semiquinone)s and their electrochemical and electron paramagnetic resonance spectral characterization}, volume={63}, ISSN={["0022-3263"]}, DOI={10.1021/jo981597s}, abstractNote={The syntheses of three new bis(semiquinone)s (2••2-, 3••2-, and 5••2-) linked through carbon−carbon double bonds in a geminal fashion (2••2- and 3••2-), and through an sp3 carbon (5••2-), are presented, as well as the results of variable-temperature EPR (VT-EPR) spectroscopy on these biradicals and two previously reported bis(semiquinone)s, 1••2- and 4••2-. We suggest that the potential difference in redox couples associated with a biradical is useful for qualitatively assessing changes in the exchange parameter within an isostructural series. The zero-field-splitting parameters for 1••2-−5••2- are consistent with their electronic structures:  biradicals 1••2-−3••2- which have conjugating groups attached to the semiquinone rings have D-values less than 5••2-, a bis(semiquinone) that lacks such a conjugating group. Also, the D-value of 3••2- is significantly less than those of 1••2- and 2••2-, in agreement with larger interelectron separation in 3••2-, a biradical with quinone-methide π-system delocalizati...}, number={25}, journal={JOURNAL OF ORGANIC CHEMISTRY}, author={Shultz, DA and Boal, AK and Farmer, GT}, year={1998}, month={Dec}, pages={9462–9469} }
 @article{shultz_boal_farmer_1997, title={The biradical, bis(3,5-di-tert-butyl-4-phenoxyl)methyleneadamantane, exhibits matrix-dependent EPR spectra suggesting rotamer bistability with differential exchange coupling}, volume={119}, ISSN={["0002-7863"]}, DOI={10.1021/ja964330o}, abstractNote={ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTThe Biradical, Bis(3,5-di- tert-butyl-4-phenoxyl)methyleneadamantane, Exhibits Matrix-Dependent EPR Spectra Suggesting Rotamer Bistability with Differential Exchange CouplingDavid A. Shultz, Andrew K. Boal, and Gary T. FarmerView Author Information Department of Chemistry North Carolina State University Raleigh, North Carolina 27695-8204 Cite this: J. Am. Chem. Soc. 1997, 119, 16, 3846–3847Publication Date (Web):April 23, 1997Publication History Received17 December 1996Published online23 April 1997Published inissue 1 April 1997https://pubs.acs.org/doi/10.1021/ja964330ohttps://doi.org/10.1021/ja964330orapid-communicationACS PublicationsCopyright © 1997 American Chemical SocietyRequest reuse permissionsArticle Views425Altmetric-Citations38LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-AlertscloseSupporting Info (1)»Supporting Information Supporting Information SUBJECTS:Aromatic compounds,Electron paramagnetic resonance spectroscopy,Exchange coupling,Hydrocarbons,Solvents Get e-Alerts}, number={16}, journal={JOURNAL OF THE AMERICAN CHEMICAL SOCIETY}, author={Shultz, DA and Boal, AK and Farmer, GT}, year={1997}, month={Apr}, pages={3846–3847} }