The Iminophosphorane Ph₃PNSiMe₃ as a Synthon for M−C_aryl σ Bonds (M = In, Fe, Ge) Implementing Imino Sidearm Donation

Abstract

Lithiation of triphenyl((trimethylsilyl)imino)phosphorane, Ph 3 PdNSiMe 3 (1), with MeLi gives the ortho-metalated species [Li(o-C 6 H 4 PPh 2 NSiMe 3 )] 2 ‚Et 2 O (2). It has all the requirements of an organometallic ligand capable of sidearm donation: the deprotonated ortho phenyl carbon atom leads to metal-carbon σ bonds in reactions with metal halides, and the Ph 2 PdNSiMe 3 moiety donates an electron pair to that metal via the imine nitrogen atom. In reactions with InCl 3 the In(III) organometallic complex [In(o-C 6 H 4 PPh 2 NSiMe 3 ) 3 ] (3) was obtained, while with FeCl 2 a new example of the rare iron(II) 14-VE complexes [Fe(o-C 6 H 4 -PPh 2 NSiMe 3 ) 2 ] (4) was obtained. Reaction of 2 with Ph 3 GeCl gave [Ph 3 Ge(o-C 6 H 4 PPh 2 -NSiMe 3 )] (5). While in 4 both imino sidearms coordinate to the metal, because of steric crowding only two of the three present coordinate in 3. Because of the low Lewis acidity of the tetraorganogermanium moiety the imino sidearm does not donate to the central germanium atom in 5.

Close contacts involving germanium and tin in crystal structures: experimental evidence of tetrel bonds

“…A close linear C-Ge···N interaction affects the conformation adopted by 1-(trimethylsilylimino(diphenyl)phosphoranyl)-2-(triphenylgermyl)benzene (Nc for Ge···N is 0.85; the C-Ge···N angle is 173.79°) (refcode VIQXIC) [83] (Fig. 12, right).…”

The Cα‐Deprotonated Iminophosphorane Ph2P(CH2Py)(NSiMe3) as an N,N‐Chelating Ligand for Iron and Zinc

“…The coordination sphere is best described as a distorted tetrahedron with the angles at the iron cation varying from 100.92 (8) to 124.40 (8)°. In the metallaspirocycle, the two six-membered FeN 2 C 2 P rings adopt a distorted boat conformation, each with the deprotonated carbon atoms C1 and C22 displaced by, on average, 45 pm (211.1 pm), [16] [Fe{2-(RNPPh 2 )-6-RЈ(c-C 5 H 3 N)}Cl 2 ] (R ϭ 2,6-Me 2 -C 6 H 3 , 2,6-iPr 2 -C 6 H 3 ; RЈ ϭ Ph, H 2 CPh, SiMe 3 ; 204.8Ϫ206.7 pm) [17] or in the 12 VE iron() complex [Fe(H 2 CPh)-{HC(CMeNAr) 2 }] (198.2 pm). [18] The FeϪN imino distances in 1 are about 24.4 pm shorter than in the dibromoiron() compound [{2,6-(Ph 2 PNSiMe 3 )Py}FeBr 2 ], where the FeϪN contacts are on average 228.8 pm, [19] reflecting the pronounced amidic character of the FeϪN imino bonds.…”

P‐Stereogenic Secondary Iminophosphorane Ligands and Their Rhodium(I) Complexes: Taking Advantage of NH/PH Tautomerism

“…[1,2] An important drawback for this class of compounds is that they are sensitive to oxidation, and therefore must be handled under a strict inert atmosphere. [5] Very recently, Reek and co-workers described the use of phosphinosulfonamide ligands 1 and 2 in rhodium-catalyzed asymmetric hydrogenation reactions (Figure 2). [3] Such a procedure is not ideal for routine screening and scale-up.…”

“…[5] Very recently, Reek and co-workers described the use of phosphinosulfonamide ligands 1 and 2 in rhodium-catalyzed asymmetric hydrogenation reactions ( Figure 2). [5] Very recently, Reek and co-workers described the use of phosphinosulfonamide ligands 1 and 2 in rhodium-catalyzed asymmetric hydrogenation reactions ( Figure 2).…”

“…Furthermore, P-stereogenic SPOs are configurationally stable and thus chiral information is preserved through the PH/OH equilibrium.The analogous equilibrium between aminophosphanes and secondary iminophosphoranes (SIPs) has not been exploited in catalysis. [5] Very recently, Reek and co-workers described the use of phosphinosulfonamide ligands 1 and 2 in rhodium-catalyzed asymmetric hydrogenation reactions (Figure 2). [6] In solution, 1 was found as 1:1.2 mixture of the corresponding aminophosphane/SIP tautomers showing a low exchange rate on the NMR timescale (RT, CDCl 3 ).…”