Synthesis and characterization of a range of antimony(I/III) N,N′-bis(2,6-diisopropylphenyl)formamidinate complexes

Abstract

Formamidinatoantimony(I/III) complexes have been successfully synthesized as monomers or dimers in the solid state featuring a variety of coordination geometries and have also been comprehensively characterized. The antimony(I) formamidinate complex bis[μ-N,N′-bis(2,6-diisopropylphenyl)formamidinato]diantimony(I)(2 Sb—Sb) tetrahydrofuran heptasolvate, [Sb2(C25H35N2)2]·7C4H8O or [Sb2(DippForm)2]·7THF, (1), was obtained by a metathesis reaction between sodium bis(trimethylsilyl)amide [NaN(SiMe3)2] and N,N′-bis(2,6-diisopropylphenyl)formamidine (DippFormH), followed by SbCl3. A range of trivalent haloformamidinatoantimony(III) complexes, namely, bis[N,N′-bis(2,6-diisopropylphenyl)formamidinato]chloridoantimony(III), [Sb(C25H35N2)2Cl] or [Sb(DippForm)2Cl], (2), bis[N,N′-bis(2,6-diisopropylphenyl)formamidinato]bromidoantimony(III), [SbBr(C25H35N2)2] or [SbBr(DippForm)2], (3), bis[N,N′-bis(2,6-diisopropylphenyl)formamidinato]iodidoantimony(III), [Sb(C25H35N2)2I] or [Sb(DippForm)2I], (4), [N,N′-bis(2,6-diisopropylphenyl)formamidinato]dibromidoantimony(III), [SbBr2(C25H35N2)] or [SbBr2(DippForm)], (5), and [N,N′-bis(2,6-diisopropylphenyl)formamidinato]diiodidoantimony(III), [Sb(C25H35N2)I2] or [Sb(DippForm)I2], (6), were also synthesized by adding DippFormH and MN(SiMe3)2 (M = Li or Na) to the corresponding antimony halides SbX 3 (X = Cl, Br or I) in differing ratios. The complexes were all stable to rearrangement.