Solvent‐free alkali and alkaline earth metal complexes of di‐imine ligands

Abstract

Compound [(dph-BIAN)Mg(THF)] 2 (2)was prepared by reacting magnesium metal with 1,2-bis [(2-biphenyl)

Recent developments in the coordination chemistry of bis(imino)acenaphthene (BIAN) ligands with s- and p-block elements

“…However, the solvent-free bis(Ar-BIAN) complexes [(dipp-BIAN 47 although in the case of the former, the dipp-BIAN ligands are present as di-anions rather than mono-anions. 46 The reactivity of compound 8 toward a wide range of organic and inorganic substrates has also been examined. For example, the reduction of Ph 2 CO with 8 affords the structurally characterized pinacolate complex [{(dipp-BIAN)Mg(THF)} 2 {m-O 2 C 2 Ph 4 }] via single electron transfer (SET), in contrast to the 1,3-dipolar cycloaddition product obtained when Ph 2 CO is treated with dianionic [(R-DAB)M] complexes (M = Group 4 or lanthanide metal).…”

Stepwise Reduction at Magnesium and Beryllium: Cooperative Effects of Carbenes with Redox Non-Innocent α-Diimines

“…As an alternative to the aforementioned low-valent alkaline earth complexes, which contain a highly reactive formally reduced metal center, substantial progress has been achieved in the study of alkaline earth complexes containing redox non-innocent ligands including α-diimines ,,− and azobenzene . The use of redox active proxy ligands allows the metal center to maintain its strongly preferred 2+ oxidation state while allowing facile, reversible electron transfers at the ligand.…”

“…Magnesium complexes containing reduced diimines such as 1,2-bis­[(2,6-diisopropylphenyl)­imino]­acenaphthene ( Dipp BIAN) and 1,4-diazabutadienes have been the subjects of a number of investigations. ,− Yang et al reported that one- and two-electron reductions of various N,N -diaryldiazabutadienes followed by reaction with MgCl 2 gave highly varied magnesium-diimine complexes depending on the ligand steric demand and reagent stoichiometry . Among the isolated products was the Mg–Mg bonded species K 2 [(L iPr )­MgMg­(L iPr )] (L iPr = [(2,6- i Pr 2 C 6 H 3 )­NC­(Me)] 2 .…”

“…It is notable, however, that in this system the coordination number of magnesium is at least 4 throughout the entire reaction sequence due to the coordination of multiple THF molecules. If donor solvents are avoided, the coordination sphere is filled either by dimerization or by ligand exchange to form a homoleptic ( Dipp BIAN) 2 Mg complex, in which each ligand is singly-reduced . These examples highlight a significant challenge in molecular group 2 chemistry: the preparation and isolation of monomeric and solvent-free group 2 complexes.…”

“…If donor solvents are avoided, the coordination sphere is filled either by dimerization or by ligand exchange to form a homoleptic ( Dipp BIAN) 2 Mg complex, in which each ligand is singly-reduced. 84 These examples highlight a significant challenge in molecular group 2 chemistry: the preparation and isolation of monomeric and solvent-free group 2 complexes. As such, our group has begun to explore the synthesis of well-defined, solvent-free carbene− alkaline earth complexes as molecular precursors.…”