Phosphine sponge

Similar behavior was observed with [cw-(IMes)RhCl(P( -tolyl)3)2], which exchanged the phosphine trans to IMes an order of magnitude more slowly than in the homoleptic complex [RhCl(P(p-tolyl)3)3], resulting in poorer hydrogenation efficiency with the NHC complex. The dissociative mechanism suggested by these observations was further corroborated by catalytic results obtained using CuCl (an effective phosphine sponge) as an additive. 

Titanium Phosphides. The titanium phosphides (154) include Ti P [12037-66-0], Ti P, and TiP (163). Titanium monophosphide [12037-65-9] TiP, can be prepared by beating phosphine with titanium tetrachloride or titanium sponge. Alternatively, titanium metal may be heated with phosphoms ia a sealed tube. The gray metallic TiP is slightly phosphoms-deficient (TiPQ has a density of 408(0) kg/m, and displays considerable... 

A wide range of Ni phosphine and arsine complexes, [Ni(L)3], [Ni(L)4] (L = PRj, AsRb, SbRs), and [Ni(LL)2] (LL = chelate ligand), can be prepared by reduction of Ni precursors in the presence of excess phosphine and arsine ligands. Alternatively, hgand replacement on [Ni(cod)2] or directly on to nickel sponge affords the same products (equations 2-4). ... 

On treatment with proton sponge 1, cationic rhodium complexes of type 262 have been shown to undergo double intramolecular dehydrofluorinative/C—C coupling to produce quantitatively rhodium complexes of hybrid cyclopentadienyl-phosphine ligands 263 (equation 27)240. 

Raab, V., Gauchenova, E., Merkoulov, A. et al. (2005) l,8-Bis(hexamethyltriaminopho-sphazenyl)naphthalene, HMPN a superbasic bisphosphazene "proton sponge . Journal of the American Chemical Society, 127, 15738-15743 Kovacevic, B., Maksic, Z.B. (2006) High basicity of tris-(tetramethylguanidyl)-phosphine imide in the gas phase and acetonitrile - a DFT study. Tetrahedron Letters, 47, 2553-2555. 

Saunders et al. have studied the G-G coupling in rhodium and iridium complexes that links fluorinated aromatic substituents on phosphine ligands to the methyl substituents of cyclopentadienyl ligands. These reactions involve HF elimination and can be induced by heat or base. The most effective bases are proton sponge (l,8-bis(dimethyl-amino)naphthalene) and BU4NF. One example is shown in Scheme ZZ ... 

Further studies on AHR of 2,3-dihydrofuran (286) with phenyl triflate afforded different products with high % ee depending on the ligands used. The isomer 287 with 96 % ee was obtained selectively when the phosphine—oxazoline ligand 291 was used [119]. On the other hand, the isomer (288) with 98% ee was the major product when (5)-MeO-BIPHEP (292) was used [120]. AHR of 283 with 289 using (R)-BITIANP (293, XV-7) in the presence of proton sponge afforded the coupling product 290 with 91 % ee selectively [121]. 

Among other new monophosphines prepared by this route are some involving an additional, non-phosphorus donor atom or group. Included among these are the proton-sponge-functionalised phosphines (11), complexes of which are readily studied by electrospray-MS techniques, a series of ortAo-sulfonyl- and ortto-sulfonamido-arylphosphines, e.g., (12), the ort/jo-phosphazenylarylphosphines (13), and the phosphino(boranyl)thiaxanthene (14). ... 

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