Phosphido complexes derived from 1,1′-ferrocenediyl-bridged secondary diphosphines

Abstract

This paper focuses on ferrocene-based secondary diphosphines of the type [Fe{η-CH(PHR)}] with P-substituents of distinctly different steric and electronic properties, namely methyl, neopentyl (Np), tert-butyl, phenyl and 3,5-bis(trifluoromethyl)phenyl (XyF). The reaction of [Fe{η-CH(PHPh)}] (H1a) and [Fe{η-CH(PHt-Bu)}] (H1b) with n-BuLi in the presence of TMEDA afforded lithium diphosphides of the type [Li(μ-1)(TMEDA)], which contain a cyclic non-planar LiP core. The analogous reactions of [Fe{η-CH(PHMe)}] (H1c) and [Fe{η-CH(PHNp)}] (H1d) furnished dimeric aggregates exhibiting a ladder-type LiP motif, viz. [Li(μ-1c)(TMEDA)] and [Li(μ-1d)(TMEDA)]. H1e (R = XyF) did not afford a stable lithium diphosphide. A Brønsted metathesis with Zr(NMe) was possible with the aryl-substituted compounds H1a and H1e, leading to products of the type [{Zr(NMe)}(μ-1)]. In contrast, the alkyl-substituted congeners H1b-H1d were inert towards Zr(NMe). The reaction of [Fe{η-CH(PHR)}] with nickelocene afforded intractable mixtures of numerous products in the case of H1c and H1e. In the other three cases, compounds of the type [(NiCp)(μ-1)] were isolated. For H1b and H1d a two-stepped reaction via a phosphino-phosphido intermediate of the type [NiCp(H1)] was observed, which could be isolated and fully characterised in the case of [NiCp(H1b)].

Metallated [3]Ferrocenophanes Containing P3M Bridges (M = Li, Na, K) §

“…The structural situation is closely related to the dilithiated bisphosphanide [Fe(Cp-P(Li)tBu) 2 ], where two phosphorus atoms are symmetrically bridged by two lithium atoms forming a P 2 Li 2 four-membered ring in the solid state and in solution [11,15]. Similarly, the spectroscopic data are comparable to the latter bisphosphanide, as well as to other dimeric lithium phosphanides [5,17].…”

“…The coordination sphere of lithium was completed by one molecule of TMEDA. The respective Li-N distances were placed with 2.113(4) Å and 2.080(4) Å in the expected range known from comparable compounds [15,16]. Owing to steric effects, the coordination geometry around lithium differed from an ideal tetrahedron with angles of 119.8(1) • to 135.6(2) • , showing larger values toward the ferrocene backbone.…”

“…In order to explore the accessibility of the sodium analog of 2, we reacted 1 with sodium hydride in the presence of [15]-crown-5 in tetrahydrofuran (THF) solution. The solution turned light-red over a period of 12 h, indicating the formation of sodium phosphanide (3, Scheme 2).…”

Low‐Valent Group 14 NHC‐Stabilized Phosphinidenide ate Complexes and NHC‐Stabilized K/P‐Clusters

“…[31] With other alkali-metal cations,e specially with lithium, more compounds with this structuralm otif or higher aggregated compounds are known. [32][33][34][35][36][37][38][39][40][41] The PÀKb ond lengthsi nt he central P 2 [42] The bond K1ÀN3 is 288.7(4) pm longer due to the additional h 2 -coordination of one toluene molecule at K1. The C=Pdistances [170.9(4)-172.7(4) pm] are slightly shortened compared with those previously mentioned.…”

Synthesis and crystal structure of μ-[1,1′-di(mesitylphosphanido)ferrocene]bis[η5-cyclopentadienylnickel(II)] tetrahydrofurane solvate, C42H48FeNi2OP2

“…We recently investigated the reaction of 1,1′-ferrocenediylbridged secondary diphosphines of the type [Fe{µ 5 -C5H4(PHR)} 2 }] with two equivalents of nickelocene [8]. …”