Reactivity of a β-diketiminate-supported magnesium alkyl complex toward small molecules

Abstract

The reactivity of the magnesium alkyl {[HC(C(Me)N-2,6-ⁱPr₂C₆H₃)₂]Mg(ⁿBu)}₂ (1) toward various small molecules provides access to a variety of magnesium derivatives. For example, the insertion of elemental chalcogens (S₈ and Se₈) into the Mg–C bond of complex 1 gives the dimeric magnesium thiolate {[HC(C(Me)N-2,6-ⁱPr₂C₆H₃)₂]Mg(μ-SⁿBu)}₂ (2), magnesium selenolate [HC(C(Me)N-2,6-ⁱPr₂C₆H₃)₂]Mg(SeⁿBu)(THF) (3), and magnesium diselenolate [HC(C(Me)N-2,6-ⁱPr₂C₆H₃)₂]Mg(Se₂ⁿBu)(THF) (4). Meanwhile, compound 4 can be readily obtained by further insertion of one selenium atom into complex 3. Moreover, the reactions of complex 1 with diphenyl dichalcogenides (PhSSPh and PhSeSePh) by σ bond metathesis afford the corresponding magnesium phenyl chalcogenolates [HC(C(Me)N-2,6-ⁱPr₂C₆H₃)₂]Mg(EPh)(THF) (E = S 5, Se 6) concomitant with PhEⁿBu release. Furthermore, the treatment of complex 1 with benzonitrile and phenyl isothiocyanate produces the serendipitous magnesium-1-azaallyl complex [HC(C(Me)N-2,6-ⁱPr₂C₆H₃)₂]Mg(N(H)C(Ph)CHC₃H₇)(DME) (7) and the diimino-thioamidato magnesium compound {κ³-N,N′,N′′-(ArNCMe)₂[N(Ph)CS]CH}Mg[(Ph)NC(ⁿBu)S] (8) (Ar = 2,6-ⁱPr₂C₆H₃). In addition, deprotonation occurs between compound 1 and 1-methylimidazole to generate the imidazolyl complex {[HC(C(Me)N-2,6-ⁱPr₂C₆H₃)₂]Mg(μ-Im)}₂ (9) (Im = 2-N-methylimidazolyl). These results indicated that the butylmagnesium complex 1 possesses high activity toward small molecules and revealed several unusual transformations. All the new compounds were characterized by various spectroscopic methods, and their solid-state structures were further confirmed by single-crystal X-ray diffraction analyses.