Diphosphanylmetallocenes of Main‐Group Elements

Abstract

Several 1,1′‐diphosphanyl‐substituted metallocenes of magnesium (magnesocenes) were synthesized, structurally characterized, and their reactivity and coordination chemistry were investigated. Transmetalation of these magnesocenes gives access to group 14 metallocenes (tetrelocenes), as well as to group 15 stibonocenes. These s‐ and p‐block metallocenes represent a novel class of bis(phosphanyl) ligands, exhibiting Lewis‐amphiphilic character. Their coordination chemistry towards different transition‐metal and main‐group fragments was investigated and different complexes are presented.

Phosphanyl-substituted tin half-sandwich complexes

“…Recently, our group reported on diphosphanylstannocenes, which exhibit moderate Lewis amphiphilic character, due to Lewis basic phosphorus centres and mildly Lewis acidic tin atoms. 10 Following established procedures for the synthesis of tin(II) half-sandwich complexes, 2,7 we reacted…”

Crystal structure of 1,1′,2,2′,4,4′-hexaisopropylmagnesocene

“…Therefore, many crystal structures of magnesocenes are actually of donor complexes, such as magnesocene mono-and bis(tetrahydrofuran) adduct, Cp 2 MgÁ(thf) and Cp 2 MgÁ(thf) 2 (Lehmkuhl et al, 1986;Jaenschke et al, 2003;Kim et al, 2007). Nevertheless, solvent-free crystal structures are also known, especially in case of highly substituted magnesocenes (Morley et al, 1987;Gardiner et al, 1991;Weber et al, 2002;Vollet et al, 2003;Deacon et al, 2015;Mu ¨ller et al, 2021). Hanusa and coworkers had reported the synthesis of 1,1 0 ,2,2 0 ,4,4 0 -hexaisopropylmagnesocene, 3 Cp 2 Mg, -calcocene, 3 Cp 2 Ca, -strontocene, 3 Cp 2 Sr, and -barocene, 3 Cp 2 Ba (the triisopropylcyclopentadienide ligand is commonly abbreviated as ' 3 Cp'), via treatment of potassium 1,2,4-triisopropylcyclopentadienide, 3 CpK, with the corresponding metal(II) bromide or iodide and described the magnesocene to be oily or waxy in composition (Burkey et al, 1993(Burkey et al, , 1994.…”

One‐Step Synthesis and Schlenk‐Type Equilibrium of Cyclopentadienylmagnesium Bromides

“…[22] In addition, bulky substituents cannot prevent adduct formation and hence, [(thf) 2 Mg{C 5 H 4 À P(iPr) 2 } 2 ] precipitates as a bis(thf) complex with η 5 -and η 2 -bonded diisopropylphosphanylcyclopentadienyl ligands. [23] In this study an improved straightforward synthesis of cyclopentadienyl magnesium bromides in ethereal solvents is presented by transferring the in situ Grignard metalation method (iGMM) to this compound class; so far this process has only been established for the synthesis of Mg{N(SiMe 3 ) 2 } 2 . [24] Furthermore, the elucidation of thermodynamic data of the temperature-dependent Schlenk equilibrium is reported.…”

“…[22] In addition, bulky substituents cannot prevent adduct formation and hence, [(thf) 2 Mg{C 5 H 4 −P( i Pr) 2 } 2 ] precipitates as a bis(thf) complex with η 5 ‐ and η 2 ‐bonded diisopropylphosphanylcyclopentadienyl ligands. [23] …”