550349-00-3Relevant academic research and scientific papers
Stabilization of the P(CF3)2- and P(C6F5)2- ions by coordination to pentacarbonyl tungsten: Structures of [18-crown-6-K]P(CF3)2, [18-crown-6-K][W{P(CF3)2}(CO)5], and [18-crown-6-K][{W(CO)5}2{μ-P(C6 F5)2}]·THF
Hoge, Berthold,Thoesen, Christoph,Herrmann, Tobias,Pantenburg, Ingo
, p. 3633 - 3641 (2003)
The stabilization of the P(CF3)2- ion by intermediary coordination to the very weak Lewis acid acetone gives access to single crystals of [18-crown-6-K]P(CF3)2. The X-ray single crystal analysis exhibits nearly isolated P(CF3)2-ions with an unusually short P-C distance of 184(1) pm, which can be explained by negative hyperconjugation and is also found by quantum chemical hybrid DFT calculation. Coordination of the P(CF3)2- ion to pentacarbonyl tungsten has only a minor effect on electronic and geometric properties of the P(CF3)2 moiety, while a strong increase in thermal stability of the dissolved species is achieved. The hitherto unknown P(C6F5)2- ion is stabilized by coordination to pentacarbonyl tungsten and isolated as a stable 18-crown-6 potassium salt, [18-crown-6-K]- [W{P(C6F5)2}(CO)5], which is fully characterized. The tungstate, [W{P(C6F5)2}(CO)5]-, decomposes slowly in solution, while coordination of the phosphorus atom to a second pentacarbonyl tungsten moiety results in an enhanced thermal stability in solution. The single-crystal X-ray analysis of [18-crown-6-K][{W(CO)5}2{μ-P(C5 F5)2}]·THF exhibits a very tight arrangement of the two C6F5 and two W(CO)5 groups around the central phosphorus atom. NMR spectroscopic investigations of the [{W(CO)5}2{μ-P(C6 F5)2}]- ion exhibit a hindered rotation of both the C6F5 and W(CO)5 groups in solution.
