Structural Methods in Molecular Inorganic Chemistry, First Edition. David W. H. Rankin, Norbert W. Mitzel and Carole A John Wiley & Sons, Ltd. Published 2013 by John Wiley & Sons, Ltd. Figure 5.1 Energy levels and EPR transitions for a single unpaired electron in an external magnetic field, (a) with no coupling and (b) with isotropic hyperfine coupling to one nucleus with spin 1/2.

Structural Methods in Molecular Inorganic Chemistry, First Edition. David W. H. Rankin, Norbert W. Mitzel and Carole A John Wiley & Sons, Ltd. Published 2013 by John Wiley & Sons, Ltd. Figure 5.2 (a) Absorption spectrum and (b) first-derivative spectrum for a Lorentzian line-shape.

Structural Methods in Molecular Inorganic Chemistry, First Edition. David W. H. Rankin, Norbert W. Mitzel and Carole A John Wiley & Sons, Ltd. Published 2013 by John Wiley & Sons, Ltd. Figure 5.3 EPR spectra (a) of [VO(acac) 2 ] [acac = CH 3 C(O)CHC(O)CH 3 ] and (b) of the benzene radical anion, [C 6 H 6 ].–

Structural Methods in Molecular Inorganic Chemistry, First Edition. David W. H. Rankin, Norbert W. Mitzel and Carole A John Wiley & Sons, Ltd. Published 2013 by John Wiley & Sons, Ltd. Figure 5.4 EPR spectra of solutions of the radical anions of (a) bptz, 5.I, (b) (  -bptz)[W(CO) 4 ] 2, 5.II, and (c) [Cp 2 Zr(H)(PhC  CPh)].

Structural Methods in Molecular Inorganic Chemistry, First Edition. David W. H. Rankin, Norbert W. Mitzel and Carole A John Wiley & Sons, Ltd. Published 2013 by John Wiley & Sons, Ltd. Figure 5.5 (a) Experimental and (b) simulated EPR spectra of the 5,5 -(CF 3 ) 2 -2,2-bipyridine radical anion using the listed experimental parameters. Courtesy of Dr A. Delf, University of Edinburgh.

Structural Methods in Molecular Inorganic Chemistry, First Edition. David W. H. Rankin, Norbert W. Mitzel and Carole A John Wiley & Sons, Ltd. Published 2013 by John Wiley & Sons, Ltd. Figure 5.6 EPR spectrum of [BH 3 ].– insolution. The stick diagram marks the resonances for the 11 B species,whichshowsa1:1:1:1quartet coupling to 11 B (I = 3/2) and a slightly smaller 1:3:3:1 coupling to three equivalent protons. The remaining weak resonances are due to the radicals containing 10 B (I = 3). Redrawn from [4] with permission of The Royal Society of Chemistry.

Structural Methods in Molecular Inorganic Chemistry, First Edition. David W. H. Rankin, Norbert W. Mitzel and Carole A John Wiley & Sons, Ltd. Published 2013 by John Wiley & Sons, Ltd. Figure 5.7 Absorption line shapes for randomly orientated systems having (a) an axis of symmetry and (b) no symmetry; (c) and (d) are first derivatives of the curves (a) and (b), respectively.

Structural Methods in Molecular Inorganic Chemistry, First Edition. David W. H. Rankin, Norbert W. Mitzel and Carole A John Wiley & Sons, Ltd. Published 2013 by John Wiley & Sons, Ltd. Figure 5.8 EPR spectrum of Li + – 13 CO 2 – ion pairs in a CO 2 matrix. Parallel and perpendicular components can be seen, each showing splittings due to 13 C and 7 Li (I = 3/2). The weak central lines are due to Li + – 12 CO 2 –. Redrawn with permission from [6]. Copyright 1981, American Institute of Physics.

Structural Methods in Molecular Inorganic Chemistry, First Edition. David W. H. Rankin, Norbert W. Mitzel and Carole A John Wiley & Sons, Ltd. Published 2013 by John Wiley & Sons, Ltd. Figure 5.9 (a) Splitting of a triplet state in an applied magnetic field. (b) Effect of a magnetic field on the energy levels of a triplet state exhibiting zero-field splitting.

Structural Methods in Molecular Inorganic Chemistry, First Edition. David W. H. Rankin, Norbert W. Mitzel and Carole A John Wiley & Sons, Ltd. Published 2013 by John Wiley & Sons, Ltd. Figure 5.10 Effect of a large zero-field splitting on a quartet system (S = 3/2). The separation induced between the M S = ±1/2 and MS = ±3/2 states is so large that only a single EPR signal, due to the M S = –½ →+1/2 transition, is observed near g = 2.0. The energies of the MS = – ½ → –3/2 and +1/2 → +3/2 transitions are outside the observable frequency range.

Structural Methods in Molecular Inorganic Chemistry, First Edition. David W. H. Rankin, Norbert W. Mitzel and Carole A John Wiley & Sons, Ltd. Published 2013 by John Wiley & Sons, Ltd. Figure 5.11 Splitting of the 4 F ground state of a d 3 ion by octahedral and tetragonal fields, showing effects of zero-field and magneticfield splittings on the lowest resultant state.

Structural Methods in Molecular Inorganic Chemistry, First Edition. David W. H. Rankin, Norbert W. Mitzel and Carole A John Wiley & Sons, Ltd. Published 2013 by John Wiley & Sons, Ltd. Figure 5.12 EPR spectra of trans-[Cr(pyridine) 4 Cl2] + at ca. 9 GHz. (a) Frozen solution in DMF/H 2 O/MeOH and (b) as a minor component of a powder consisting mainly of trans-[Rh(pyridine) 4 Cl 2 ]Cl 6 H 2 O. Computer fitting of the complicated patterns is necessary to obtain information about g tensors and zero-field splitting, but the spectra of powder and glass samples are very similar. Redrawn with permission from [9]. Copyright 1974 American Chemical Society.

Structural Methods in Molecular Inorganic Chemistry, First Edition. David W. H. Rankin, Norbert W. Mitzel and Carole A John Wiley & Sons, Ltd. Published 2013 by John Wiley & Sons, Ltd. Figure 5.13 Splittings of the 2 D ground state of a d 9 ion by an octahedral ligand field, with Jahn–Teller distortion, showing the effect of a magnetic field on the 2 A state.

Structural Methods in Molecular Inorganic Chemistry, First Edition. David W. H. Rankin, Norbert W. Mitzel and Carole A John Wiley & Sons, Ltd. Published 2013 by John Wiley & Sons, Ltd. Figure 5.14 (a) EPR spectrum of the binuclear copper(II) porphyrin complex shown in (b). This is the derivative form of a spectrum shown in [10].

Structural Methods in Molecular Inorganic Chemistry, First Edition. David W. H. Rankin, Norbert W. Mitzel and Carole A John Wiley & Sons, Ltd. Published 2013 by John Wiley & Sons, Ltd. Figure 5.15 Energy-level diagram for a system with one unpaired electron and one nucleus with spin 1/2. The terms  e  n etc. refer to the spin states of the electron and nucleus.

Structural Methods in Molecular Inorganic Chemistry, First Edition. David W. H. Rankin, Norbert W. Mitzel and Carole A John Wiley & Sons, Ltd. Published 2013 by John Wiley & Sons, Ltd. Figure 5.I and 5.II

Structural Methods in Molecular Inorganic Chemistry, First Edition. David W. H. Rankin, Norbert W. Mitzel and Carole A John Wiley & Sons, Ltd. Published 2013 by John Wiley & Sons, Ltd. Figure 5.III

Structural Methods in Molecular Inorganic Chemistry, First Edition. David W. H. Rankin, Norbert W. Mitzel and Carole A John Wiley & Sons, Ltd. Published 2013 by John Wiley & Sons, Ltd. Review Question Figure 5.3

Structural Methods in Molecular Inorganic Chemistry, First Edition. David W. H. Rankin, Norbert W. Mitzel and Carole A John Wiley & Sons, Ltd. Published 2013 by John Wiley & Sons, Ltd. Review Question Figure 5.12

Structural Methods in Molecular Inorganic Chemistry, First Edition. David W. H. Rankin, Norbert W. Mitzel and Carole A John Wiley & Sons, Ltd. Published 2013 by John Wiley & Sons, Ltd. Review Question Figure 5.16

Structural Methods in Molecular Inorganic Chemistry, First Edition. David W. H. Rankin, Norbert W. Mitzel and Carole A John Wiley & Sons, Ltd. Published 2013 by John Wiley & Sons, Ltd. Review Question Figure 5.17