Fig. 5
From: Muon spectroscopy of a 12-phosphatetraphene with extremely efficient radical trapping properties
(a) A normally optimized structure of 1Mu. Hydrogen was used instead of Mu at the UB3LYP/def2-SVP level. (b) The alternative structure of 1Mu maintains a flat tetracyclic system with an increased total energy of 1.59 kcal/mol. Modifying the C3···P–Mu(H) angle to 103° with increasing total energy (0.86 kcal/mol) provides the almost identical muon and 31P hfc constants of 304.5 and 128.3 MHz, respectively, to the experimentally determined Aµ (307 MHz) and \($$A_{^{31}{\rm P}}$$\) (128 MHz) values. (c) The spin density (iso = 0.006, blue: α spin, green: β spin) of the modified structure from (b) indicates the delocalization of the unpaired electron over the planar tetracyclic skeleton. (d) Simulated µLCR spectra for the DFT-calculated structures of 1Mu (c), C6-Mu, and C7-Mu (see Fig. 6).
