Diverse Reactivity of a Ca(I) Synthon

Abstract

Abstract Low‐valent Mg I complexes like (BDI)Mg−Mg(BDI) have found wide‐spread application as specialty reducing agents (BDI= β ‐diketiminate). Also their redox reactivity was extensively investigated. In contrast, attempts to isolate similar Ca I complexes led to reduction of the aromatic solvents or N 2 . Complex ( DIPeP BDI)Ca( μ 6 , μ 6 ‐C 6 H 6 )Ca( DIPeP BDI) ( VIII ) should be regarded a Ca II complex with a bridging C 6 H 6 2− dianion ( DIPeP BDI=HC[C(Me)N‐DIPeP] 2 , DIPeP=2,6‐C(H)Et 2 ‐phenyl). It can react as a Ca I synthon by releasing benzene and two electrons. Herein we describe the reactivity of VIII with benzene, biphenyl, naphthalene, anthracene, COT, Ph 3 SiCl, PhSiH 3 , a (BDI)AlI 2 complex, H 2 , PhX (X=F, Cl, Br, I), t BuOH and t BuCH 2 I. The C 6 H 6 2− dianion in VIII can react as a 2 e − source, a nucleophile or a Brønsted base. In some cases radical reactivity cannot be excluded. Crystal structures of ( DIPeP BDI)Ca( μ 8 , μ 8 ‐COT)Ca( DIPeP BDI) ( 1 ) and [( DIPeP BDI)CaX ⋅ (THF)] 2 (X=F, Cl, Br, I) ( 2 – 5 ) are described.