Umpolung Asymmetric 1,5-Conjugate Addition via Palladium Hydride Catalysis.

Electronically matched nucleophilic 1,6-conjugate addition has been well studied and widely applied in synthetic areas. In contrast, nucleophilic 1,5-conjugate addition represents an electronically forbidden process and is considered unfeasible. Here, we describe modular protocols for 1,5-conjugate addition reactions via palladium hydride catalysis.

Single-molecule magnet behaviour in a dysprosium-triradical complex.

The first triradical bridged binuclear penta-spin single-molecule magnet, [Dy2(hfac)6(BTR)], based on a nitronyl nitroxide triradical was synthesized and characterized. Theoretical calculations revealed Dy-radical antiferromagnetic coupling and radical-radical ferromagnetic coupling. The SMM behavior is found to originate from the exchange states, rather than the isolated Dy3+ center.

A family of lanthanide compounds with reduced nitronyl nitroxide diradical: syntheses, structures and magnetic properties.

A novel nitronyl nitroxide diradical based on the pyrazine ring, BNITPz (1, BNITPz = 2,2'-(3,6-dimethylpyrazine-2,5-diyl)bis(1-hydroxy-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-1-oxyl-3-oxide)) and six new dinuclear compounds based on the reduced form of 1, namely [Ln(hfac)3]2(BHIMPz)(H2O)2 (Ln = Gd (2Gd), Dy (3Dy), Ho (4Ho), Er (5Er), Tm (6Tm), Yb (7Yb); BHIMPz = 2,2'-(3,6-dimethylpyrazine-2,5-diyl)bis(4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide); hfac = hexafluoroacetylacetonate) were prepared and characterized. Single crystal X-ray crystallographic analyses confirmed the diradical structure of 1, and revealed that complexes 2Gd-7Yb are isostructural and crystallize in the triclinic space group P1[combining macron]. The reduced form BHIMPz was confirmed by its longer N-O bond lengths and the characteristic N-H stretching absorption at 3500-3300 cm-1 of the IR spectroscopy of 2Gd-7Yb.

Syntheses, structures and magnetic properties of the lanthanide complexes of the pyrimidyl-substituted nitronyl nitroxide radical.

Four 2p-4f Ln-radical complexes, [(NIT-2-Pm)Ln(hfac)]·0.5CH (NIT-2-Pm = 2-pyrimidyl-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1-oxy-3-oxide, hfac = hexafluoroacetylacetonato, Ln = Tb (1), Dy (2), Ho (3) and Er (4)), and four 4f-2p-4f Ln-radical-Ln complexes, [(μ-NIT-2-Pm)Ln(hfac)(HO)]·0.5CH (Ln = Tb (5), Dy (6), Ho (7) and Er (8)) have been synthesized and characterized structurally and magnetically.