1. Structure, Electronics and Reactivity of Ce(PNP) Complexes.
- Author
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Zabula, Alexander V., Qiao, Yusen, Kosanovich, Alex J., Cheisson, Thibault, Manor, Brian C., Carroll, Patrick J., Ozerov, Oleg V., and Schelter, Eric J.
- Subjects
CERIUM compounds ,ELECTRONIC structure ,REACTIVITY (Chemistry) ,COORDINATE covalent bond ,X-ray diffraction ,NUCLEAR magnetic resonance spectroscopy - Abstract
Synthetic methods for the coordination of the monoanionic bis[2-(diisopropylphosphino)-4-methylphenyl]amido (PNP) ligand framework to the cerium(III) cation have been developed and applied for the isolation of a series of {(PNP)Ce} and {(PNP)
2 Ce} type complexes. The structures of the complexes were studied by X-ray diffraction and multinuclear NMR spectroscopy. We found that the cerium(III) ion can induce the elimination of one of the iPr groups at phosphorus to yield a new dianionic PNP tridentate framework (PNP- iPr ) featuring a phosphido-donor functionality, which is bound to the cerium ion with the shortest known Ce−P bond of 2.7884(14) Å for molecular compounds. The reaction of the complex [(PNP)Ce{N(SiMe3 )2 }2 ] ( 1) with Ph2 CO gave the Ce-bound product of C−C coupling,- N(SiMe3 )SiMe2 CH2 -CPh2 O− , through the C−H bond activation of a SiMe3 group.31 P NMR spectroscopy was used to estimate the presence of a vacant coordination position at the cerium ion in the CeIII -PNP complexes by the examination of the δ(31 P) shift recorded both in non-polar (C6 D6 ) and polar ([D8 ]THF) solvents. Moreover,31 P NMR spectroscopy was also found to be a useful tool for the estimation of the Ce−P bond distances in {(PNP)CeIII } and {(PNP)2 CeIII } systems. Electrochemical and computational studies for 1 and its lanthanum analogue containing a redox-innocent metal center revealed the stabilization of the CeIII oxidation state by the PNP ligand. [ABSTRACT FROM AUTHOR]- Published
- 2017
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