Dimeric (Tris(tert-butyl)silyl)phosphanyl (Tris(tert-butyl)silyl)phosphanediyl Gallane: A Molecule with a Ga−P−Ga Heteroallyl System

Abstract

The metathesis reaction of potassium (tris(tert-butyl)silyl)phosphanide with GaCl(3) in a molar ratio of 1:1 leads to the formation of [Cl(2)GaP(H)Si(t)Bu(3)](2) (1) as a mixture of cis and trans isomers with very large (1)J(P,H) and (2)J(P,P) coupling constants. The molecular structure of 1 shows a Ga(2)P(2) cycle with nearly planar coordinated phosphorus atoms under neglection of the hydrogen atoms and Ga-P distances of 239 pm. The reaction of GaCl(3) with 3 equiv of potassium (tris(tert-butyl)silyl)phosphanide as well as the reaction of 1 with 2 equiv of KP(H)Si(t)Bu(3) yields [(t)Bu(3)SiP(H)Ga(mu-PSi(t)Bu(3))](2) (2). The central moiety comprises a four-membered Ga(2)P(2) cycle with one planar P atom and extremely short Ga-P bonds of approximately 226 pm, the other being in a pyramidal environment with an angle sum of 298.4 degrees. The structure of 2 can be described as a GaPGa heteroallyl system which is bonded to a phosphanidyl substituent. This idea and its dependency on the steric demand of the trialkylsilyl groups are investigated by DFT calculations on different isomers of 2.

Coordination of phosphanide and trialkylsilylphosphanide ligands at pentacarbonyltungsten fragments: An NMR spectroscopic and structural investigation

“…The solvent was removed under reduced pressure, and red oil of [((OC) 5 W) 2 (3). A hexane solution of n-BuLi (4.8 mL of a 2.5 M hexane solution) was added dropwise to a solution of [((OC) 5 W) 2 PH 2 ]Li (10 mmol) in 50 mL of THF at -78…”

“…A solution of (thf)W(CO) 5 (0.35 mmol) in 5 mL of THF was slowly added to a suspension of KPHSi(iPr) 3 (153 mg, 0.67 mmol) in 10 mL of THF at -78…”

“…de solubility in common organic solvents or to prevent side and decomposition reactions. Sterically hindered trialkylsilyl groups such as SiiPr 3 and SitBu 3 have been used to stabilize various classes of compounds. Only very few but representative examples are the copper(I) tri(tert-butyl)silylphosphanediide from Wiberg and coworkers [1] and the central Ca 4 P 4 heterocubane moiety in (thf) 2 [2].…”

“…Only very few but representative examples are the copper(I) tri(tert-butyl)silylphosphanediide from Wiberg and coworkers [1] and the central Ca 4 P 4 heterocubane moiety in (thf) 2 [2]. Furthermore, these demanding trialkylsilyl substituents are able to stabilize unique fragments as, for example, the extraordinary Ga-P-Ga heteroallyl system in dimeric tri(tert-butyl)-silylphosphanediyl gallium tri(tert-butyl)silylphosphanide [3]. The coordination of a pentacarbonyltungsten moiety at the lone pair of phosphorus atom lowers the oligomerization degree and allows the investigation of small but reactive molecules.…”

Synthesis and characterization of 1,3-bis[2,4,6-tri(tert-butyl)phenyl]-2,4-bis[tri(tert-butyl)silyl]-1,3-diinda-2,4-diphosphetane, a dimeric phosphanylidene indane with three-coordinate indium and phosphorus atoms

“…The monomeric digallylphosphane MesP{Ga(Trip) 2 } 2 AE Et 2 O [6] (Trip = 2,4,6-iPr 3 C 6 H 2 ) contains a planar three-coordinate phosphorus center. In [tBu 3 SiP(H)-Ga(l-PSitBu 3 )] 2 a Ga-P-Ga heteroallylic system with one planarily coordinated P atom (Ga-P 225.8 pm) is realized, the other bridging phosphorus atom (Ga-P 233.6 pm) is in a pyramidal environment [7]. Only very few dimeric phosphanylindanes with In 2 P 2 cycles such as [(allyl) 2 InPtBu 2 ] 2 [8], [Et 2 InP (SiMe 3 ) 2 ] 2 [1], and [Ph 2 InP(SiMe 3 ) 2 ] 2 [9] with fourcoordinate indium and phosphorus atoms have been synthesized.…”