Coordination and Oligomerisation of the Siloxanephosphane Cage Compound [P₂{(SiMe₂)₂O}₃]

Abstract

Die Reaktivität der Aminogruppe P‐stereogener Aminophosphane ermöglicht Folgereaktionen mit der Aminophosphaneinheit, bei denen die Chiralität am Phosphoratom erhalten bleibt (siehe Bild; Rh grün). P‐stereogene Aminodiphosphanliganden sind einfach in optisch reiner Form zugänglich, weisen charakteristische elektronische und Strukturmerkmale auf und können in asymmetrischen Hydrierungen eingesetzt werden.

Synthesis and Coordination of the Cagelike Siloxane Compounds E2{(SiMe2)2O}3 (E = As, Sb, Bi)

“…Metal complexes with cyclosiloxane compounds as ligands have been investigated since the early 1990s. The first cyclosiloxane complex was reported by Churchill et 4 . [2] In 2006, Passmore et al obtained cyclosiloxane complexes directly by the reaction of alkali-metal ions with the cyclodimethylsiloxane (Me 2 SiO) n (n = 5, 6) when using a salt of a weakly coordinating anion.…”

“…Some years ago, we reported on the synthesis of the bicyclic siloxane compounds P 2 {(SiMe 2 ) 2 O} 3 (1) [4] and [P 2 {(SiiPr 2 ) 2 O} 2 {Me 2 Si(OSiMe 2 ) 2 }] (2) [5] with phosphorus bridgehead atoms (Scheme 1). Compound 2 can host a lithium cation within the cage structure, whereas 1 showed the formation of the complex [Li@P 4 {(SiMe 2 ) 2 O} 6 ] + with the dimeric ligand P 4 {(SiMe 2 ) 2 This class of compounds can be considered as inorganic equivalents of the organic cryptands as Ritch and Chivers mentioned.…”

“…(M = Al, E = As, Sb; M = Ga, E = Sb) Lewis acid-base adducts were formed as well as the W(CO) 5 adduct of compound 1 and a heteroleptic Na[Al(OR F ) 4 ] (R F = C(CF 3 ) 3 ) adduct with 4 to investigate the coordination properties of the cage compounds. The structural changes caused by coordination follow the Haaland model, which gives qualitative information on the adduct stability.…”

“…Furthermore, to obtain information on the coordination properties of these compounds, we investigated the reactions with the Lewis acids AlEt 3 , GaEt 3 , and [W(CO) 5 (thf)] (thf = tetrahydrofuran) as well as with the lithium and sodium salts M[Al(OR F ) 4 ]. AsH 2 ] (dme = dimethoxyethane) in diethyl ether.…”

“…The assumptions made by the Haaland model are valid for a versatile set of Lewis acids. To investigate coordination on the inside of the cage, a reaction of 4 with Li[Al(OR F ) 4 ] was performed to yield a new dimeric ligand of the constitution As 4 [(SiMe 2 ) 2 O] 6 .…”