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Structure, Electronics and Reactivity of Ce(PNP) Complexes
Author(s) -
Zabula Alexander V.,
Qiao Yusen,
Kosanovich Alex J.,
Cheisson Thibault,
Manor Brian C.,
Carroll Patrick J.,
Ozerov Oleg V.,
Schelter Eric J.
Publication year - 2017
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201703174
Subject(s) - cerium , chemistry , ligand (biochemistry) , reactivity (psychology) , nuclear magnetic resonance spectroscopy , lanthanum , crystallography , coordination complex , stereochemistry , medicinal chemistry , inorganic chemistry , metal , organic chemistry , medicine , biochemistry , alternative medicine , receptor , pathology
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 i Pr groups at phosphorus to yield a new dianionic PNP tridentate framework (PNP ‐ i Pr ) 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(SiMe 3 ) 2 } 2 ] ( 1 ) with Ph 2 CO gave the Ce‐bound product of C−C coupling, ‐ N(SiMe 3 )SiMe 2 CH 2 ‐CPh 2 O − , through the C−H bond activation of a SiMe 3 group. 31 P NMR spectroscopy was used to estimate the presence of a vacant coordination position at the cerium ion in the Ce III –PNP complexes by the examination of the δ ( 31 P) shift recorded both in non‐polar (C 6 D 6 ) and polar ([D 8 ]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)Ce III } and {(PNP) 2 Ce III } systems. Electrochemical and computational studies for 1 and its lanthanum analogue containing a redox‐innocent metal center revealed the stabilization of the Ce III oxidation state by the PNP ligand.