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

Abstract

The photophysical properties of the compound [(ThiaSO2)(MnII)2(DMF)4(H2O)2] (2), ThiaSO2 = p‐tert‐butylsulfonylcalix[4]arene, are presented and compared to the ones of [(ThiaSO2)2(MnII)4F]K (1). The orange luminescence of 2 is attributed, as for 1, to the MnII centred 4T1→6A1 transition and shows, for this type of complex, the weak influence of the Mn2+ coordination and ThiaSO2 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 4T1 state exciting dioxygen to its 1Σ+g state and is responsible for the photosynthesis of the [(ThiaSO2)(MnIII)(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.

Mono-, Di-, and Tetranuclear Manganese(II) Complexes with p-Phenylsulfonylcalix[4]arene Macrocycles as Ligand Antennas: Synthesis, Structures, and Emission Properties

“…The emission of complex 2 is weaker and red-shifted when compared to that of the previously reported dinuclear complex [Mn 2 (ThiaSO 2 )(DMF) 4 (H 2 O) 2 ] (7). 23 These effects are in agreement with the observation that absorption decreases from ThiaSO 2 to ppThiaSO 2 macrocycles acting as an antenna.…”

“…Thus, a dinuclear compound [Mn 2 II (ThiaSO 2 )-(DMF) 4 (H 2 O) 2 ] (7) was synthetized, where the ThiaSO 2 macrocycle adopts a 1,2-alternated conformation instead of a cone one (Figure S1). 23 Compound 7 is also luminescent, and the emission maximum is red-shifted compared to that of tetranuclear complexes (4−6). For all these molecular systems (4−7), solid-state emission is centered on the Mn(II) ions and activated by the antenna effect of the sulfonylcalix [4]arene macrocycle (Scheme 1).…”

Impact of flexible succinate connectors on the formation of tetrasulfonylcalix[4]arene based nano-sized polynuclear cages: structural diversity and induced chirality study

“…Among the accessible metacyclophanes, one should mention the calix[4]arene 11 (1-4H, figure 1) and, especially, thiacalix[4]arene 12 (2-4H, figure 1) as well as tetrasulfonylcalix[4]arene 13,14 (3-4H, figure 1) based polydentate macrocyclic ligands, owing to the preorganized orientation of the coordinating sites, when adopting their cone conformation. They possess the fascinating ability to form various polynuclear homo-and heterometallic clusters when coordinated to d/f metal cations 15,16,17,18,19 exhibiting attractive luminescence properties 20,21,22,23,24,25,26 and magnetic behavior. 27,28,29,30,31,32,33,34 Also using 1-4H and 2-4H in cone conformation as a building species, the formation of extended coordination networks in the crystalline phase was extensively documented.…”

Thiacalix[4]arene-Protected Titanium–Oxo Clusters: Influence of Ligand Conformation and Ti–S Coordination on the Visible-Light Photocatalytic Hydrogen Production

“…Even better, if different conformations of TC4A can be achieved, the electronic structures of the PTCs may be fine-tuned, as the ligand bears a conformationdependent π-conjugate system over the entire molecular structure. 31,49,52,53 The possibility of directly comparing the photophysical properties and the underlying electronic structure offers a valuable opportunity to establish the structure−property relationship in this class of important photocatalysts.…”

“…Recent studies have revealed that the substitution of O for S in certain TiO 2 -based nanomaterials significantly improved their visible-light photocatalytical activities. , We suspect that the anticipated S coordination in place of O on the cluster core may alter the electronic structure of the resulting complexes in a similar fashion. Even better, if different conformations of TC4A can be achieved, the electronic structures of the PTCs may be fine-tuned, as the ligand bears a conformation-dependent π-conjugate system over the entire molecular structure. ,,, The possibility of directly comparing the photophysical properties and the underlying electronic structure offers a valuable opportunity to establish the structure–property relationship in this class of important photocatalysts.…”