Samarium and ytterbium complexes based on sterically hindered 1,2-bis(imino)acenaphthene*

Reactions of the samarium complex [(Ar-BIG-bian)Sm-2-(2+)] (1) (Ar-BIG-bian is the 1,2-bis-[(2,6-dibenzhydryl-4-methylphenyl)imino]acenaphthene dianion) with iodine (0.5 mol. equiv.) or triphenyltin chloride lead to the oxidation of the metal and afford the corresponding derivatives [(Ar-BIG-bian)2-Sm3+I(dme)] (2) and [(Ar-BIG-bian)2-Sm3+Cl(dme)] (3). Meanwhile, the reaction of the related ytterbium complex [(Ar-BIG-bian)Yb-2-(2+)(dme)] (4) with iodine (2:1) or copper(I) chloride resulted in the oxidation of the dianionic ligand rather than the metal to form the compounds [(Ar-BIG-bian)-Yb2+I(dme)] (5) and [(Ar-BIG-bian)-Yb2+Cl](2) (6), respectively. The reaction of 2 with one molar equivalent of potassium pentamethylcyclopentadienide gave the adduct [(Ar-BIG-bian)Sm-2-(3+)(I)Cp*][K(dme)(4)] (7). The reaction of samarium complex 1 with 2,2 '-bipyridine (bipy) (1:2) is accompanied by the oxidation of Sm-II to Sm-III to form the derivative [(Ar-BIG-bian)Sm-2-(3+)(bipy)(2)] (8) containing the radical-anion and neutral bipy ligands. The coordination of a neutral bipyridine molecule to the metal atom in ytterbium iodine complex 5 leads to the metal-ligand electron transfer giving [(Ar-BIG-bian)2-Yb3+I(bipy)] (9). All the newly synthesized compounds 2, 3, and 5-9 were characterized by IR spectroscopy (complexes 5 and 6 were also characterized by EPR spectroscopy) and elemental analysis. The molecular structures of complexes 2, 3, and 5-9 were determined by X-ray diffraction.

Automated summary

The study discovered the oxidation of samarium and ytterbium complexes using iodine or triphenyltin chloride, resulting in the synthesis of various new compounds characterized by IR spectroscopy and elemental analysis, with the molecular structures of some compounds determined by X-ray diffraction.