0000000000122263
AUTHOR
Ulrich Schatzschneider
Nitronyl Nitroxide Radicals Linked to Exchange‐Coupled Metal Dimers – Studies Using X‐ray Crystallography, Magnetic Susceptibility Measurements, EPR Spectroscopy, and DFT Calculations
To study long-range magnetic interactions between exchange-coupled metal centers and a radical moiety coordinated through a peripheral group, three new homodimetallic complexes with MnII, CoII, and ZnII bridged by a nitronyl nitroxide (NIT) substituted benzoate ligand with the structure [(NIT-C6H4-COO)M2(LR)](ClO4)2 {M = MnII, CoII, and ZnII; NIT = nitronyl nitroxide and LR = N,N,N′,N′-tetrakis(2-benzimidazolylalkyl)-2-hydroxy-1,3-diaminopropane} have been prepared and studied by X-ray crystallography, magnetic susceptibility measurements, EPR spectroscopy, and density functional theory calculations. For comparison, related complexes with MnII and CoII bridged by a diamagnetic nitrobenzoate…
Long-Distance Magnetic Interaction of Exchange-Coupled Copper Dimers with Nitronyl Nitroxide and tert-Butyl Nitroxide Radicals
To study long-distance magnetic interactions between exchange-coupled metal centers and coordinated radical moieties, two new homodimetallic Cu(II) complexes held together by the chelating ligand L(nPr) = N,N,N',N'-tetrakis(N-propyl-2-benzimidazolyl)-2-hydroxy-1,3-diaminopropane and additionally bridged by either a nitronyl nitroxide (NIT) or a tert-butyl nitroxide (NOA) radical-substituted benzoate have been prepared. The complexes have been investigated by X-ray crystallography, magnetic susceptibility measurements, electron paramagnetic resonance (EPR) spectroscopy, and density functional theory (DFT) calculations. For comparison additionally the related copper dimer with the bridging di…
Experimental and Theoretical Studies on Magnetic Exchange in Silole-Bridged Diradicals.
International audience; Five bis(tert-butylnitroxide) diradicals connected by a silole [2,5-R2-3,4-diphenylsilole; R = Me3CN(®O.bul.)Z; Z = p-C6H4 (7a), p-C6H4C6H4-p (7b), 1,4-naphthalenediyl (7c), m-C6H4 (7d)] or a thiophene [2,5-R2-thiophene; R = p-Me3CN(®O.bul.)C6H4 (12)] ring as a coupler were studied. Compd. 12 crystallizes in the orthorhombic space group Pna21 with a 20.752(5), b 5.826(5), and c 34.309(5) .ANG.. X-ray crystal structure detn., electronic spectroscopy, variable-temp. EPR spectroscopy, SQUID measurements and DFT computations (UB3LYP/6-31+G*) were used to study the mol. conformations and electronic spin coupling in this series of mols. Whereas compds. 7b, 7c, and 7d are q…
Integrated experimental and computational spectroscopy study on the protonation of the α-nitronyl nitroxide radical unit
The stability of the α-nitronyl nitroxide radical unit under acidic conditions is investigated by an integrated experimental UV/Vis spectroscopy and TDDFT study. In the field of molecular magnetism, α-nitronyl nitroxide radicals are important as purely organic spin carriers due to their synthetic versatility. Here, the existence of an intermediate of the protonated α-nitronyl nitroxide radical unit is demonstrated for the first time and a proposed disproportionation reaction is confirmed.