Redox Active Hexanuclear Mixed Valence Dicationic Ce(III)/Ce(IV) Coordination Clusters

Abstract

A series of mixed valence hexanuclear dicationic coordination clusters containing two µ4‐O2– bridges with general formula M2+(X–)2 [M = CeIV2CeIII4(µ4‐O)2(L–R)4(val)6(H2O)2; 12+, 32+: R = H, 22+: Me; 12+, 22+: X = CeIII2(val)3(NO3)4, 32+: X = NO3] were synthesized, isolated and characterized. The reaction of cerium(III)nitrate hexahydrate with Schiff base ligand (H2L–R) and o‐vanillin (val‐H) under basic condition led to the formation of M2+(X–)2 and the reaction progress was monitored by mass spectrometric studies. The molecular structures of all complexes were unambiguously characterized by single‐crystal X‐ray diffraction. The magnetic susceptibility measurements of M2+(X–)2 showed that the Ce(III) ions are weakly antiferromagnetically coupled. Thermal stability and molar conductivity of M2+(X–)2 were also studied. Complex 32+(X–)2 was further studied by X‐ray photoelectron spectroscopy to confirm the oxidation states of Ce(III/IV) ions. The M2+ cation was shown to catalyze the TEMPO‐free oxidation of functionalized benzyl alcohols quantitatively to the corresponding benzaldehyde derivatives at 100 °C in presence of aerial O2 using DMF as the solvent.

Quick and robust PDF data acquisition using a laboratory single-crystal X-ray diffractometer for study of polynuclear lanthanide complexes in solid form and in solution

“…Polynuclear lanthanide complexes are of high interest owing to wide possible applications for luminescence sensors (Kreno et al, 2012), thermometers (D'Vries et al, 2013) and markers (Ga ´lico et al, 2021), for magnetic data storage (Xiong et al, 2017) and magnetic refrigeration (Wang et al, 2019;, as secondary building blocks for metal-organic framework (MOF) design (Feng et al, 2020), and as nanoparticles with atomic-precision size control (Russell-Webster et al, 2020) and catalytic properties (Mitchell et al, 2021;Arumugam et al, 2020).…”

Molecular Terpyridine–Lanthanide Complexes Modified Carbon Nitride for Enhanced Photocatalytic CO2 Reduction

“…For Ce 4+ , the peaks at 882.2, 888.5, and 898.4 eV belong to 3d 5/2 while peaks at 900.8, 907, and 916.6 eV belong to 3d 3/2 . It has been found that Ce 3+ coordinated by nitrogen donor ligands can spontaneously undergo oxidation to produce Ce 4+ under aerobic conditions . Since CetpyCN is stored in an aerobic environment after synthesis, it is assumed that the presence of Ce 4+ is due to the partial oxidation of Ce 3+ to Ce 4+ .…”

“…44 It has been found that Ce 3+ coordinated by nitrogen donor ligands can spontaneously undergo oxidation to produce Ce 4+ under aerobic conditions. 45 Since CetpyCN is stored in an aerobic environment after synthesis, it is assumed that the presence of Ce 4+ is due to the partial oxidation of Ce 3+ to Ce 4+ . Due to the introduction of terpyridine−lanthanide complexes, the fractions of elements and functional groups of LutpyCN and CetpyCN differ from those of CN (Tables S1−S3).…”

Dual‐State Emissive π‐Extended Salicylaldehyde Fluorophores: Synthesis, Photophysical Properties and First‐Principle Calculations

“…[15] However, unlike acetophenones or benzophenones analogs, [16] salicylaldehyde derivatives display reduced chelating ability toward metal or metalloid ions, unless an additional chelating group is inserted in the vincinity. [17] Nevertheless, some coordination complexes involving salicylaldehyde derivatives have been described. [18] Salicylaldehydes derivatives typically display weak emission in solution due to the possibility of Excited-State Intramolecular Proton Transfer (ESIPT) emission, owing to the presence of 6-membered H-bonded ring.…”