Syntheses of Pyrazolato- and Formamidinato-lanthanoid(III) Diiodides from in Situ Generated lanthanoid(III) Pseudo-Grignard Reagents

Halim, Md Abdul;Guo, Zhifang;Blair, Victoria L.;Deacon, Glen B.;Junk, Peter C.

Abstract

Trivalent lanthanoid pseudo-Grignard reagents PhpLnIIII(3-p) (P=1 or 2; Ln=La, Ce, Nd, Er and Lu) are readily prepared by the oxidation of lanthanoid metals with iodobenzene at 25 °C, following pre-activation of the metal with 1 drop Hg in tetrahydrofuran (thf) or acetonitrile (CH3CN) and brief sonication. The protolysis of PhpLnIIII(3-p) with 3,5-diphenylpyrazole (Ph2pzH) yields pyrazolato complexes [Ln(Ph2pz)I2(thf)n] (n=4: Ln=La 1, Ce 2, Nd 3; n=3: Ln=Er 4, Lu 5). Interestingly, for Er, a competing complex [ErPh(Ph2pz)I(thf)3]⋅thf (4 a) was obtained along with the expected [Er(Ph2pz)I2(thf)3] (4). In contrast, in CH3CN, [Ln(Ph2pz)3(CH3CN)3]⋅2CH3CN (Ln=Nd 6, Gd 7) complexes were obtained through Schlenk equilibrium redistribution. Reactions with bulky N,N′-bis(2,6-di-isopropylphenyl)formamidine (DippFormH) and N,N’ –bis(2,6-dimethylphenyl)formamidine (XylFormH) produced the Ln(III) complexes, [Ln(DippForm)I2(thf)3]⋅nthf (n=1, Ln=Nd 8; n=0.5, Ln=Er 9) and [Ln(XylForm)I2(thf)3]⋅thf (Ln=Nd 10, Er 11). All the complexes isolated in this study are monomeric; 4–5 and 8–11 are seven coordinate, complexes 1–3 are eight coordinate with one η2-N-donor ligand and two trans iodine ligands, and complexes 6–7 are nine coordinate, featuring three η2-Ph2pz ligands, and three CH3CN ligands.

Journal

European Journal of Inorganic Chemistry

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European Journal of Inorganic Chemistry

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1099-0682

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Wiley

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DOI

10.1002/ejic.202400672