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Synthesis and decomposition behavior of pallada(IV)cyclopentane complexes


Canty, AJ and Hoare, JL and Davies, NW and Traill, PR, Synthesis and decomposition behavior of pallada(IV)cyclopentane complexes, Organometallics, 17, (10) pp. 2046-2051. ISSN 0276-7333 (1998) [Refereed Article]

DOI: doi:10.1021/om980005t


The octahedral pallada(IV)cyclopentane complexes PdX(C4H8)R(bpy) [RX = MeI (1), EtI (2), PhCH2Br (3), CH2=CHCH2Br (4); bpy = 2,2′-bipyridine] may be isolated on oxidative addition of organohalides to the palladium(II) complex Pd(C4H8)(bpy) in acetone at -20 °C. The complex PdBr(C4H8)(CF3)(bPy) (5) has been generated in solution but was too unstable to permit isolation as a solid. Complex 1 occurs as a mixture of isomers in a 4:1 ratio, where the dominant isomer has the methyl group trans to bpy and the minor isomer has 2-fold symmetry with the methyl group trans to the iodo ligand. Complexes 2-5 adopt only the configuration with R trans to X. The complexes exhibit low stability, allowing studies of decomposition in solution under mild conditions in CDCls or CD2Cl2. Formation of the major products from PdI(C4H8)Me(bpy) (1) and PdI(C4H8)Et(bpy) (2) is assumed to result from C4H8⋯R coupling at Pd(IV) to give undetected PdIICH2CH2CH2CH2R species which undergo β-elimination to form alkenes (48% of detected organic products), Pd(0), and HX, with subsequent protonation Of PdIICH2CH2CH2CH2R to give alkanes (39%). Complexes 1 and 2 also give iodopentane (∼12% from 1) and iodohexane (∼9% from 2). The complex PdBr(C4H8)(CH2Ph)(bpy) (3) gives phenylpentane (15%), phenylpentenes (66%), toluene (10%), and butenes (8%); PdBr(C4H8)(CH2CH=CH2)(bpy) (4) and PdI(C4H8)(CF3)(bpy) (5) give predominantly cyclobutane, together with minor amounts of butenes (4, 5) and propene (4). Deuteration studies implicate the occurrence of intermolecular hydrogen atom transfer for elimination of alkenes and alkanes, except for cyclobutane.

Item Details

Item Type:Refereed Article
Research Division:Chemical Sciences
Research Group:Inorganic chemistry
Research Field:Organometallic chemistry
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the chemical sciences
UTAS Author:Canty, AJ (Professor Allan Canty)
UTAS Author:Hoare, JL (Mr Jason Lancelot Hoare)
UTAS Author:Davies, NW (Associate Professor Noel Davies)
UTAS Author:Traill, PR (Mr Peter Traill)
ID Code:14066
Year Published:1998
Web of Science® Times Cited:28
Deposited By:Chemistry
Deposited On:1998-08-01
Last Modified:2011-08-09

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