Photogeneration of Manganese(III) from Luminescent Manganese(II) Complexes with Thiacalixarene Ligands: Synthesis, Structures and Photophysical Properties

The photophysical properties of the compound [(ThiaSO 2 )(Mn II ) 2 (DMF) 4 (H 2 O) 2 ] ( 2 ), ThiaSO 2 = p ‐ tert ‐butylsulfonylcalix[4]arene, are presented and compared to the ones of [(ThiaSO 2 ) 2 (Mn II ) 4 F]K ( 1 ). The orange luminescence of 2 is attributed, as for 1 , to the Mn II centred 4 T 1 → 6 A 1 transition and shows, for this type of complex, the weak influence of the Mn 2+ coordination and ThiaSO 2 conformation on this luminescence, the temperature and pressure dependence and quenching by molecular dioxygen of which are reported for 2 . The latter is attributed to energy transfer from the 4 T 1 state exciting dioxygen to its 1 Σ + g state and is responsible for the photosynthesis of the [(ThiaSO 2 )(Mn III )(DMF) 2 ]Na ( 3 ) complex in DMF solution from 1 or 2 . This reaction was studied by UV/Visible and EPR spectroscopy. The molecular structure and EPR spectroscopy of 3 are also presented.