p-Toluenethiolate manganese(II) porphyrin complexes: Structure and spectroscopic properties

Utilizing tetraphenylporphyrin (TPP), tetratolylporphyrin (TTP), tetramesitylporphyrin (TMP), and tetra- p -chlorophenylporphyrin (T p ClPP) as ligands, several five-coordinate high-spin p -toluenethiolate Manganese(II) complexes are isolated and studied by UV-vis, single-crystal X-ray and EPR spectroscopies. The crystal structures show noteworthy features including flexible axial p -toluenethiolate ligands and intramolecular C−H ⋅ ⋅ ⋅ π and π - π interactions between ligands and porphyrin planes. All four products are further studied by X-band EPR on both solid and solution states at 4 K which confirmed the S = 2/5 high-spin states. Temperature-dependent EPR and measurements with different equivalents of ligands are also reported for comparison. The work provides new references for the study of the active center of P450s and the biochemical reaction between cysteine residues and heme.