Synthesis of Piano Stool Complexes Employing the Pentafluorophenyl-Substituted Diphosphine (C6F5)2PCH2P(C6F5)2 and the Effe
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- 作者：Andrew C. Marr ; Mark Nieuwenhuyzen ; Ciara L. Pollock ; Graham C. Saunders
- 刊名：Organometallics
- 出版年：2007
- 出版时间：May 7, 2007
- 年：2007
- 卷：26
- 期：10
- 页码：2659 - 2671
- 全文大小：308K
- 年卷期：v.26,no.10(May 7, 2007)
- ISSN：1520-6041
文摘
Ruthenium, rhodium, and iridium piano stool complexes of the pentafluorophenyl-substituteddiphosphine (C6F5)2PCH2P(C6F5)2 (2) have been prepared and structurally characterized by single-crystalX-ray diffraction. The 
5,
P-Cp-P tethered complex [{(5,P-C5Me4CH2C6F4-2-P(C6F5)CH2P(C6F5)2}RhCl2] (9), in which only one phosphorus is coordinated to the rhodium, was prepared by thermolysis ofa slurry of [Cp*RhCl(
-Cl)]2 and 2 and was structurally characterized by single-crystal X-ray diffraction.The tethering occurs by intramolecular dehydrofluorinative coupling of the 5-pentamethylcyclopentadienylligand and P,P-coordinated 2. The geometric changes that occur on tethering force dissociation of oneof the phosphorus atoms. The effects of introducing phosphine ligands to the coordination sphere ofpiano stool hydrogen transfer catalysts have been studied. The complexes of fluorinated phosphinecomplexes are found to transfer hydrogen at rates that compare favorably with leading catalysts, particularlywhen the phosphine and cyclopentadienyl functionalities are tethered. The highly chelating 5,P,L-Cp-PP complex [(5,P,P-C5Me4CH2-2-C5F3N-4-PPhCH2CH2PPh2)RhCl]BF4 (1) was found to outperform all other complexes tested. The mechanism of hydrogen transfer catalyzed by piano stool phosphinecomplexes is discussed with reference to the trends in activity observed.
5,P-Cp-P tethered complex [{(5,P-C5Me4CH2C6F4-2-P(C6F5)CH2P(C6F5)2}RhCl2] (9), in which only one phosphorus is coordinated to the rhodium, was prepared by thermolysis ofa slurry of [Cp*RhCl(-Cl)]2 and 2 and was structurally characterized by single-crystal X-ray diffraction.The tethering occurs by intramolecular dehydrofluorinative coupling of the 5-pentamethylcyclopentadienylligand and P,P-coordinated 2. The geometric changes that occur on tethering force dissociation of oneof the phosphorus atoms. The effects of introducing phosphine ligands to the coordination sphere ofpiano stool hydrogen transfer catalysts have been studied. The complexes of fluorinated phosphinecomplexes are found to transfer hydrogen at rates that compare favorably with leading catalysts, particularlywhen the phosphine and cyclopentadienyl functionalities are tethered. The highly chelating 5,P,L-Cp-PP complex [(5,P,P-C5Me4CH2-2-C5F3N-4-PPhCH2CH2PPh2)RhCl]BF4 (1) was found to outperform all other complexes tested. The mechanism of hydrogen transfer catalyzed by piano stool phosphinecomplexes is discussed with reference to the trends in activity observed.