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

Caspar N. de Bruin-Dickason, Glen B. Deacon, Cameron Jones, Peter C. Junk, Michal Wiecko

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1 Citation (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)1030-1038
Number of pages9
JournalEuropean Journal of Inorganic Chemistry
Volume2019
Issue number7
DOIs
Publication statusPublished - 21 Feb 2019

Keywords

  • Alkaline earth metals
  • Heavy Grignard chemistry
  • N ligands
  • Structure elucidation

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