Thermodynamic Studies of Hydride Transfer for a Series of Niobium and Tantalum Compounds
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- 作者：Niladri Sarker and Joseph W. Bruno
- 刊名：Organometallics
- 出版年：2001
- 出版时间：January 8, 2001
- 年：2001
- 卷：20
- 期：1
- 页码：55 - 61
- 全文大小：81K
- 年卷期：v.20,no.1(January 8, 2001)
- ISSN：1520-6041
文摘
Reported herein are the first thermodynamic hydricities (
GM+) for a collection of nioboceneand tantalocene compounds (1-13) of general formulas (C5R4R')2M(H)(L) (R = H, Me; R' =H, Me, SiMe3; L = CO, PEt3, (H)2, PhCCPh, CH2=O, =O) and (C5H4SiMe3)2Nb(Cl)(L') (L' =O=C=CEtPh, O=C=CEt2). The studies were carried out in acetonitrile solution, and thecompounds show hydride transfer free energies ranging from 74 to 95 kcal/mol, as determinedby bracketing studies involving a known series of hydride acceptors. The data indicate thatthe free energies of hydride transfer are heavily influenced by coligands, but less so by 4dvs 5d effects in isostructural niobium or tantalum compounds.
GM+) for a collection of nioboceneand tantalocene compounds (1-13) of general formulas (C5R4R')2M(H)(L) (R = H, Me; R' =H, Me, SiMe3; L = CO, PEt3, (H)2, PhCCPh, CH2=O, =O) and (C5H4SiMe3)2Nb(Cl)(L') (L' =O=C=CEtPh, O=C=CEt2). The studies were carried out in acetonitrile solution, and thecompounds show hydride transfer free energies ranging from 74 to 95 kcal/mol, as determinedby bracketing studies involving a known series of hydride acceptors. The data indicate thatthe free energies of hydride transfer are heavily influenced by coligands, but less so by 4dvs 5d effects in isostructural niobium or tantalum compounds.