chlorides 12 with AgBF4 and M[NTsX] (M = Na or K; i.e., haloamine-T) provided access to the corresponding Mn(III) haloamide complex 13 (Figure ; for characterization of the intermediate [MnL]BF4 complexes, see Supporting Information). The spectroscopic data for iodoamide 13e is representative of the family of haloamides and is described in detail here; for characterization details of the other haloamide complexes, see the Supporting Information. The 1 H NMR spectrum of 13e displays three paramagnetically shifted peaks, which integrate as expected for the assigned structure (Figure ). The UV-vis spectrum of 13e displays absorbances at 383 nm (ε = 3.5 × 10 M -1 cm -1 ), 479 nm (ε = 5.2 × 10 4 M -1 cm -1 ), 585 nm (ε = 7.8 × 10 3 M -1 cm -1 ), and 620 nm (ε = 8.2 × 10 3 M -1 cm -1 ), which we assign as ligand-to-metal charge-transfer (LMCT), Soret, and Q-bands respectively, based on comparison to other Mn(III) porphyins. Based on the ratio of the molar absorptivities of the two Q-bands and the position of the Soret band, the ligand field strength of the N-iodoamide ligand is similar to that of chloride (i.e., Mn(TPP)Cl) and the ligand field strength of the haloamide ligands examined here is not sensitive to the identity of the N-halogen (Table ). Consistent with the S = 2 ground state typical of Mn(III) porphyrin complexes, compound 13e displays a magnetic moment of 4.9 (Evans method, 23 °C) and does not display X-band EPR features at 4 K (2-Me-THF glass). Due to the lack of X-band EPR features for S = 2 compounds, we pursued high-frequency and -field EPR (HFEPR) spectroscopic characterization of this suite of complexes (for spectra and resonance field versus microwave frequency plots of 13a, 13d, and 13e see Figures ). The spectra consist of very broad signals apparently due to the presence of slightly different Mn moieties (two in 13a, 13d, and 13e). Representative HFEPR spectra recorded at 319 GHz of the MnNXTs(TPP) X = Cl, Br, I series are illustrated in Figure and the derived spin Hamiltonian parameters (zero field splitting (ZFS): axial (D), rhombic (E) values, and g values) are collected in Table . The present study is the first, to our knowledge, to provide the ZFS parameters of a Mn(III) tetrapyrrole with a nitrogen-donor axial ligand. The D values of the compounds measured here are similar to each other and to other Mn(III) tetrapyrroles (i.e., D = -2.5 ± 0.5 cm -1 ) bearing O-or N-bound axial ligands. Substitution of the amido halogen substituent has minimal impact on the D value, with D becoming slightly less negative from 13a to 13d to 13e. This trend is significantly more dramatic in the corresponding MnX(TPP) series in which the halogen is bound directly to the Mn center. This observation is a consequence of the extensive spin-orbit coupling of heavier donors. The rhombicity does show a more significant dependence on the halogen identity, where 13a is the least rhombic and 13e is the most. We hypothesize that the high rhombicity value of MnNXTs(TPP) is due to the Ts-N-X apical unit breaking the four-fold symmetry observed in manganese tetrapyrroles, which generally feature rhombicity values close to zero, even in the case of corroles/corrolazines, which lack the true four-fold symmetry of the porphyrin macrocycle. Qualitatively, Mn-N p-bonding from N px (filled N lone pair) to Mn dxz (half-filled), but not correspondingly from N py to Mn dyz would distinguish the in-plane x and y directions (the principal ZFS direction is along z, normal to the porphyrin plane). Figure . HF-EPR spectra of 13a, 13d, and 13e collected at 319 GHz and 10 K. Blue: experimental; red: simulated with parameters given in Table . The asterisk indicates an impurity signal at g = 2.003.