Nucleophilic Phosphinidene Complexes: Access and Applicability

Abstract

Syntheses, properties, and reactivities of nucleophilic phosphinidene complexes [L(n)M=P-R] are reviewed. Emphasis is placed on the electronic tuning of this emerging class of phosphorus reagents, using different ancillary ligands and coordinatively unsaturated transition-metal moieties. The difference in applicability of the established stable 18-electron and transient 16-electron phosphinidenes is addressed.

Synthesis and Structural Characterization of the First Thermally Stable, Neutral, and Electrophilic Phosphinidene Complexes of Vanadium

“…The chemistry of these two classes of molecules is now being intensively explored. 4,21,22,[27][28][29] (ii) The presence and nature of metal-main group element multiple bonding (MdP, MtP) in these complexes is of theoretical and reactivity interest. 30 (iii) In terminal M-PR molecules, the phosphorus atom is in a low oxidation state (þ1) and coordination number (2), providing an opportunity to explore fundamentally different chemistry at a P(I) center.…”

“…(iv) Like metal-carbene complexes, phosphinidene analogues have considerable potential in phosphaorganic synthesis and catalytic chemistry. 4 Our own interest in terminal phosphinidene complexes was stimulated by a longstanding interest in chemical transformations at bridging, μ-PR ligands in clusters 32,33 and by the discovery in 2001 of a synthetic route to isolable, cationic, terminal phosphinidene complexes of molybdenum and tungsten, [Cp*M(CO) 3 34 At the time these were the first fully characterized, electrophilic, terminal phosphinidene complexes, although NMR spectroscopic evidence had been reported 35 for a related iron cation, [Cp*Fe(CO) 2 …”

“…þ , and the phosphaorganic chemistry of transient electrophilic phosphinidenes such as [(CO) 5 WdPR] and [(CO) 4 FedPR)],generatedinsitu,hadbeen e l e g a n t l ye x p l o r e db yM a t h e y 36 and co-workers and Lammertsma et al 37 The Lammertsma group has recently reported the direct observation of the phosphinidene complex [W(CO) 5 (η 1 -PAr)] (Ar = aryl) by electrospray ionization tandem mass spectrometry (ESI-MS/MS), and the chemistry displayed by this reactive species matches that observed in solution. 38 Over the past few years we have isolated a series of cationic, terminal complexes including the remaining member [Cp*Cr(CO) 3 -{PN 21,[23][24][25]34 These molecules, all of which have been structurally characterized, display several important features.…”

Hydride Abstraction and Deprotonation – an Efficient Route to Low Coordinate Phosphorus and Arsenic Species

“…A solution of 1b (600 mg, 1.98 mmol) in THF (10 mL) was added dropwise to a stirred suspension of Ph 3 C·BF 4 (655 mg, 1.98 mmol) in THF (10 mL) and stirred at room temperature for 2 h. The resultant white precipitate was collected by filtration, washed with diethyl ether (10 mL) and dried in vacuo to afford 2b (580 mg, 1.49 mmol, 75%) as a fine white powder. Crystals suitable for single crystal X-ray diffraction were grown from slow diffusion of diethyl ether into a concentrated solution of 2b in CDCl 3 …”

“…Transition metal stabilised phosphanylidene-σ 4 -phosphoranes (R 3 P=P(R)→ML n ) were first synthesised by Mathey and co-workers in 1990 [1] and have received attention as "phosphaWittig" reagents for the generation of P=C bonds, in which they act as phosphinidene (R-P) transfer reagents. [2][3][4][5][6] Free phosphanylidene-σ 4 -phosphoranes are rather reactive species, with only a handful of published examples where the compound is stabilised by extremely electron withdrawing substituents, [7,8] steric shielding, [9][10][11] or the combination of a rigid backbone and steric shielding. [12] Low co-ordinate arsenic chemistry is significantly less studied than that of phosphorus, with most attention being focused on arsaalkenes (R 2 C=AsR'), diarsenes (RAs=AsR), [13][14][15][16] and phosphine-and carbene-stabilised cationic species.…”