Functionalised Alkaline Earth Iodides from Grignard Synthons “PhAeI(thf) n ” (Ae = Mg‐Ba)

Derivatisation of Grignard synthons “PhAeI(thf) n ” (Ae = Mg‐Ba) prepared in situ from reactions of metal filings and iodobenzene provides a one‐pot synthesis of heteroleptic N donor alkaline earth iodide complexes. Protolysis of “PhAeI(thf) n ” with 3,5‐diphenylpyrazole (Ph 2 pzH) yields pyrazolate complexes [Mg 2 (µ‐Ph 2 pz) 2 (I) 2 (thf) 3 ] ( 1 ), [Ae(Ph 2 pz)(I)(thf) 4 ] (Ae = Ca ( 2 ), Sr ( 3 )), and [Ba 2 (Ph 2 pz) 2 (µ‐I) 2 (thf) 8 ] ( 4 ). Addition of the Ae‐Ph moiety to carbodiimide MesN=C=NMes (Mes = 2,4,6‐(CH 3 ) 3 C 6 H 2 ) gave a series of benzamidinate iodide complexes [Ca 2 {(MesN) 2 CPh} 2 (µ‐I) 2 (thf) 4 ] ( 6) , [Sr{(MesN) 2 CPh}(I)(thf) 4 ] ( 7 ), and [{Ba{(MesN) 2 CPh}(µ‐I)(thf) 3 } ∞ ] ( 8 ). By contrast a symmetrical magnesium complex [Mg{(MesN) 2 CPh} 2 (thf)] ( 5 ) was obtained by Schlenk redistribution. These syntheses proceed without pre‐activation of the metal for strontium and barium, and after activation with 2 mol‐% iodine for calcium. The heavy alkaline earth metal complexes are the first examples of heteroleptic halide pyrazolate or amidinate complexes for strontium and barium. Complexes 1 , 3 , 4 and 6–8 were characterised crystallographically, revealing diverse structural chemistry of heteroleptic amidinate and pyrazolate iodide complexes across the alkaline earth series. A highlight is [Ba{(MesN) 2 CPh}(µ‐I)(thf) 3 ] ∞ ( 8 ) – an iodide bridged infinite 1‐D polymer.