Search results
Results from the WOW.Com Content Network
It is poorly soluble in hexane and cold diethyl ether. Trituration or chromatography of crude products with these solvents often leads to a good separation of triphenylphosphine oxide. Its removal is facilitated by conversion to its Mg(II) complex, which is poorly soluble in toluene or dichloromethane and can be filtered off. [7]
Triphenylphosphine undergoes slow oxidation by air to give triphenylphosphine oxide, Ph 3 PO: 2 PPh 3 + O 2 → 2 OPPh 3. This impurity can be removed by recrystallisation of PPh 3 from either hot ethanol or isopropanol. [8] This method capitalizes on the fact that OPPh 3 is more polar and hence more soluble in polar solvents than PPh 3.
The structure of the phosphine oxide is not strongly perturbed by coordination. The geometry at phosphorus remains tetrahedral. The P-O distance elongates by ca. 2%. In triphenylphosphine oxide, the P-O distance is 1.48 Å. [3] In NiCl 2 [OP(C 6 H 5) 3] 2, the distance is 1.51 Å (see figure).
The hydrolysis of phosphorus(V) dihalides also affords the oxide: [9] R 3 PCl 2 + H 2 O → R 3 PO + 2 HCl. A special nonoxidative route is applicable secondary phosphine oxides, which arise by the hydrolysis of the chlorophosphine. An example is the hydrolysis of chlorodiphenylphosphine to give diphenylphosphine oxide: Ph 2 PCl + H 2 O → Ph ...
The situation for phosphorus-carbon couplings are more complicated since the two-bond couplings are often larger than one-bond couplings. The J(13 C, 31 P) values for triphenylphosphine are respectively −12.5, 19.6, 6.8, and 0.3 for one-, two-, three-, and four-bond couplings. [4]
It is a white, water-insoluble solid that is soluble in organic solvents. In solution it slowly converts to the phosphine oxide. As a phosphine ligand, it has a wide cone angle of 194°. Consequently, it tends to cyclometalate when treated with metal halides and metal acetates. Complexes of this ligand are common in homogeneous catalysis. [1]
The reaction mechanism of the Mitsunobu reaction is fairly complex. The identity of intermediates and the roles they play has been the subject of debate. Initially, the triphenyl phosphine (2) makes a nucleophilic attack upon diethyl azodicarboxylate (1) producing a betaine intermediate 3, which deprotonates the carboxylic acid (4) to form the ion pair 5.
Solubility in water. decompose Solubility: THF Except where otherwise noted, ... The phosphorus-containing product is triphenylphosphine oxide. Structure