Rationalization of Anomalous Pseudocontact Shifts and Their Solvent Dependence in a Series of C-Symmetric Lanthanide Complexes.
Bleaney's long-standing theory of magnetic anisotropy has been employed with some success for many decades to explain paramagnetic NMR pseudocontact shifts, and has been the subject of many subsequent approximations. Here, we present a detailed experimental and theoretical investigation accounting f...
| Publicado en: | Journal of the American Chemical Society Vol. 139; no. 40; pp. 14166 - 14173 |
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| Autores principales: | , , , , , , , , |
| Formato: | Artículo |
| Publicado: |
American Chemical Society
10/11/2017
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| Materias: | |
| Acceso en línea: | Ver este registro en EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=hlh&AN=125688907&site=ehost-live header: @attributes: shortDbName: hlh uiTerm: 125688907 longDbName: Humanities International Complete uiTag: AN controlInfo: bkinfo: jinfo: jid: 00027863 ACS jtl: Journal of the American Chemical Society issn: 00027863 maglogo: N pubinfo: dt: 10/11/2017 vid: 139 iid: 40 pid: 997 pub: American Chemical Society artinfo: ui: 125688907 10.1021/jacs.7b07094 ppf: 14166 ppct: 7 formats: tig: atl: Rationalization of Anomalous Pseudocontact Shifts and Their Solvent Dependence in a Series of C-Symmetric Lanthanide Complexes. aug: au: Vonci, Michele Mason, Kevin Suturina, Elizaveta A. Frawley, Andrew T. Worswick, Steven G. Kuprov, Ilya Parker, David McInnes, Eric J. L. Chilton, Nicholas F. affil: School of Chemistry, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K. Department of Chemistry, Durham University, South Road, Durham DH1 3LE, U.K School of Chemistry, The University of Southampton, Highfield, Southampton SO17 1BJ, U.K. su: Magnetic anisotropy Rare earth metals Magnetic susceptibility Magnetic resonance Triazacyclononane Electronic structure sug: subj: Magnetic anisotropy Rare earth metals Magnetic susceptibility Magnetic resonance Triazacyclononane Electronic structure ab: Bleaney's long-standing theory of magnetic anisotropy has been employed with some success for many decades to explain paramagnetic NMR pseudocontact shifts, and has been the subject of many subsequent approximations. Here, we present a detailed experimental and theoretical investigation accounting for the anomalous solvent dependence of NMR shifts for a series of lanthanide(III) complexes, namely [LnL¹] (Ln = Eu, Tb, Dy, Ho, Er, Tm, and Yb; L¹: 1,4,7-tris[(6-carboxypyridin-2-yl)methyl]-1,4,7-triazacyclononane), taking into account the effect of subtle ligand flexibility on the electronic structure. We show that the anisotropy of the room temperature magnetic susceptibility tensor, which in turn affects the sign and magnitude of the pseudocontact chemical shift, is extremely sensitive to minimal structural changes in the first coordination sphere of L¹. We show that DFT structural optimizations do not give accurate structural models, as assessed by the experimental chemical shifts, and thus we determine a magnetostructural correlation and employ this to evaluate the accurate solution structure for each [LnL¹]. This approach allows us to explain the counterintuitive pseudocontact shift behavior, as well as a striking solvent dependence. These results have important consequences for the analysis and design of novel magnetic resonance shift and optical emission probes that are sensitive to the local solution environment and polarity. pubtype: Academic Journal doctype: Article src: R language: English refInfo: copyright: @attributes: flag: Y dt: @attributes: year: 2017 holdings: @attributes: islocal: N |
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