Kristall‐ und Molekülstruktur von Bis[1,2‐bis(diphenyl‐phosphino)‐ethan]nickel(O)

Abstract

Die Titelverbindung [Ni(dppe)2] (dppe  Ph2PCH2CH2PPh2) kristallisiert in der monoklinen Raumgruppe P21/n mit den Gitterkonstanten a = 983,2(2), b = 2119,2(3), c = 2145,1(4) pm, β = 91,97(1)° und vier Molekülen pro Elementarzelle. Die Struktur wurde auf der Grundlage von 2779 beobachteten symmetrieunabhängigen Reflexintensitäten nach der Schweratommethode gelöst und bis zu einem R‐Wert von 0,063 (RW = 0,052) verfeinert. Das Ni‐Atom als Spirozentrum ist verzerrt tetraedrisch von den vier P‐Atomen der beiden zweizähnigen Chelatliganden umgeben. Die sehr ähnlichen Ni‐P‐Abstände weisen einen Mittelwert von 216(1) pm auf. Der aus der Molekülstruktur von [Ni(dppe)2] berechnete mittlere Öffnungswinkel für den Tolman‐Kegel von dppe beträgt 129,8°.

The tetrahedral tetrakis(phosphine) complex [bis(diphenylphosphino)butane-κP,P]nickel(0)–benzene (1/2.5)

“…As expected, the PÐNiÐP and NiÐPÐC angles in the chelate ring of (II) are larger than those of related complexes having shorter bridges between the P atoms, e.g. [Ni(dcpm) 2 ] (dcpm = Cy 2 PCH 2 PCy 2 ) (Kru È ger & Tsay, 1972) and [Ni(dppe) 2 ] (dppe = Ph 2 P(CH 2 ) 2 PPh 2 ) (Hartung et al, 1989). The average angle values for these complexes are given in Table 2, together with the 31 P NMR chemical shifts of the corresponding diphenylphosphine species (Fisher & Alyea, 1989).…”

The First Catalytic Synthesis of an Acrylate from CO2 and an Alkene—A Rational Approach

“…[18] Thus, we first systematically studied the influence of the length of the carbon bridge [-CH 2 A C H T U N G T R E N N U N G (CH 2 ) n -(n = 0-2)] in the backbone of bisphosphine ligands 1 a-f, containing either phenyl or tert-butyl substituents at the phosphorus atoms, on the selectivity of the oxidative coupling to yield nickelalactones 2 a-f (Table 1). Although complexes based on bis(diphenylphosphino)methane (dppm, 1 a) formed aggregates, [20] those based on the homologues 1,2-bis(diphenylphosphino)ethane (dppe, 1 b) [21] and 1,3-bis(diphenylphosphino)propane (dppp, 1 c) [22] rapidly formed the tetracoordinate Ni 0 species [NiA C H T U N G T R E N N U N G (dppe) 2 ] (4 b) [23,24] and [NiA C H T U N G T R E N N U N G (dppp) 2 ] (4 c) [25,26] in 65 and 24 % yield, respectively. Even after a reaction time of 72 h, none of the nickelalactones…”

Bis[1,3-bis(diphenylphosphino)propane-κ2P,P′]nickel(0)

“…The structure of the related compound [Ni(dppe) 2 ], (II), where dppe is 1,2-bis(diphenylphosphino)ethane, has been reported previously (Hartung et al, 1989). The distorted tetrahedral coordination about the Ni atom is similar in both molecules, with bond lengths to the Ni atom in (II) lying in the range 2.152 (3)-2.177 (3) Å .…”