title: A Soft Grip: Magnesium Complexes with a Phosphine-Modified Phosphonium Diylidic Lewis Base.
abstract: Simple strategies to obtain magnesium complexes with the soft chelating diylidic ligand [Ph2PCHPPh2(fluorenylidene)]-(dppmflu-) were developed to evaluate the influence of the hard acid (cation) and soft base (anion) mismatch on the stability and reactivity of the formed derivatives. Deprotonation of the precursor Ph2PCH2PPh2(flu) (dppmfluH) by an alkylmagnesium derivative or magnesium amide provided access to [{Mg(dppmflu)(μ-nBu)}2], [Mg(dppmflu){N(SiMe3)2}], and [{Mg(dppmflu)(μ-Me)}2], which were used as starting materials for further investigations. The reaction of [{Mg(dppmflu)(μ-nBu)}2] with PhSiH3in the presence of THF allowed isolation of the magnesium hydride complex [{Mg(dppmflu)(μ-H)(thf)}2] without a stabilizing nitrogen donor ligand. Prolonged heating enforced ligand redistribution and [{Mg(dppmflu)(μ-H)(thf)}2] was converted to [Mg(dppmflu)2] and MgH2. The homoleptic derivative [Mg(dppmflu)2], in which the magnesium center is in a very soft ligand environment, can open a THF molecule by frustrated Lewis pair reactivity to give [{Mg(dppmflu)(μ-OC4H8dppmflu)}2].
authors: Inorganic and Organometallic Chemistry, Friedrich-Alexander University Erlangen-Nürnberg, Egerlandstraße 1, 91058, Erlangen, Germany.|Inorganic and Analytical Chemistry, Friedrich-Schiller University Jena, Humboldtstraße 8, 07743, Jena, Germany.
authors: Jens
authors: http://orcid.org/0000-0002-2895-4979
authors: J
authors: Langer
authors: Inorganic and Organometallic Chemistry, Friedrich-Alexander University Erlangen-Nürnberg, Egerlandstraße 1, 91058, Erlangen, Germany.
authors: Irina
authors: I
authors: Kosygin
authors: Inorganic and Organometallic Chemistry, Friedrich-Alexander University Erlangen-Nürnberg, Egerlandstraße 1, 91058, Erlangen, Germany.
authors: Ralph
authors: R
authors: Puchta
authors: Inorganic and Organometallic Chemistry, Friedrich-Alexander University Erlangen-Nürnberg, Egerlandstraße 1, 91058, Erlangen, Germany.
authors: Jürgen
authors: J
authors: Pahl
authors: Inorganic and Organometallic Chemistry, Friedrich-Alexander University Erlangen-Nürnberg, Egerlandstraße 1, 91058, Erlangen, Germany.
authors: Sjoerd
authors: S
authors: Harder
keywords: acid-base pairs; frustrated Lewis pair; hydrides; magnesium; phosphane ligands