Solid state π–π stacking and higher order dimensional crystal packing, reactivity, and electrochemical behaviour of salphenazine actinide and transition metal complexes

Uranyl(VI) complexes with pentadentate N 3 O 2 -donating Schiff base ligands having various substituents at the ortho (R 1 ) and/or para (R 2 ) positions on phenolate moieties, R 1 ,R 2 -Me saldien 2− , were synthesized and thoroughly characterized by 1 H nuclear magnetic resonance, infrared, elemental analysis, and single-crystal X-ray diffraction. Molecular structures of UO 2 (R 1 ,R 2 -Me saldien) are more or less affected by the electron-donating or -withdrawing nature of the substituents. The redox behavior of all UO 2 (R 1 ,R 2 -Me saldien) complexes was investigated to understand how substituents introduced onto the ligand affect the redox behavior of these uranyl(VI) complexes. As a result, the redox potentials of UO 2 (R 1 ,R 2 -Me saldien) in dimethyl sulfoxide increased from −1.590 to −1.213 V with an increase in the electron-withdrawing nature of the substituents at the R 1 and R 2 positions. The spectroelectrochemical measurements and theoretical calculation [density functional theory (DFT) and timedependent DFT calculations] revealed that the center U 6+ of each UO 2 (R 1 ,R 2 -Me saldien) complex undergoes one-electron reduction to afford the corresponding uranyl(V) complex, [UO 2 (R 1 ,R 2 -Me saldien)] − , regardless of the difference in the substituents. Consequently, the redox active center of uranyl(VI) complexes seems not to be governed by the redox potentials but to be determined by whether the LUMO is centered on a U 5f orbital or on one π* orbital of a surrounding ligand.

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Tunable ligand emission of napthylsalophen triple-decker dinuclear lanthanide(iii) sandwich complexes

Hardy

Wyss

Keller

et al. 2018

Dalton Trans.

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The fluorescent ligand 1,1'-((1E,1'E)-(1,2-phenylenebis(azanylylidene))bis(methanylylidene)) bis(naphthalen-2-ol) (HL) was used to prepare lanthanide(iii) metal complexes. These were found to self-assemble as triple decker sandwich complexes of the type (LnL), where Ln = Pr(iii), Nd(iii), Sm(iii), Eu(iii), Gd(iii), Tb(iii), Dy(iii), Ho(iii), Er(iii), Yb(iii), or Lu(iii). The structures of the complexes NdL, GdL, TbL, DyL, HoL, YbL, and LuL are structurally characterized by single crystal X-ray diffraction. In the NdL complex, both metals are 8 coordinate. YbL, TbL, DyL, and LuL are isostructural. In these, as in the GdL and HoL complexes, one metal is 8 coordinate, one 7 coordinate. The ligand was found to have tunable emission in the solid state across the lanthanide series with a maximum at 556 nm for the SmL complex to 617 nm for ErL. Of these, most demonstrate only ligand-centered fluorescence at room temperature. The ligand was found to have much greater fluorescence in the complex LuL. Here, we describe these distinctive triple decker complexes and their absorption and emission properties as both solids and solutions.

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Solid state π–π stacking and higher order dimensional crystal packing, reactivity, and electrochemical behaviour of salphenazine actinide and transition metal complexes

Cited by 3 publications

References 50 publications

Deaggregation properties and transmetalation studies of a zinc(ii) salen-type Schiff-base complex

Deaggregation properties and transmetalation studies of a zinc(ii) salen-type Schiff-base complex

Effects of Substituents on the Molecular Structure and Redox Behavior of Uranyl(V/VI) Complexes with N₃O₂-Donating Schiff Base Ligands

Tunable ligand emission of napthylsalophen triple-decker dinuclear lanthanide(iii) sandwich complexes

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Solid state π–π stacking and higher order dimensional crystal packing, reactivity, and electrochemical behaviour of salphenazine actinide and transition metal complexes

Cited by 3 publications

References 50 publications

Deaggregation properties and transmetalation studies of a zinc(ii) salen-type Schiff-base complex

Deaggregation properties and transmetalation studies of a zinc(ii) salen-type Schiff-base complex

Effects of Substituents on the Molecular Structure and Redox Behavior of Uranyl(V/VI) Complexes with N3O2-Donating Schiff Base Ligands

Tunable ligand emission of napthylsalophen triple-decker dinuclear lanthanide(iii) sandwich complexes

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Effects of Substituents on the Molecular Structure and Redox Behavior of Uranyl(V/VI) Complexes with N₃O₂-Donating Schiff Base Ligands