Open AccessMild sp2Carbon–Oxygen Bond Activation by an Isolable Ruthenium(II) Bis(dinitrogen) Complex: Experiment and Theory
Author(s) -
Samantha Lau,
Bryan J. Ward,
Xueer Zhou,
Andrew J. P. White,
Ian J. Casely,
Stuart A. Macgregor,
Mark R. Crimmin
Publication year - 2017
Publication title -
organometallics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.231
H-Index - 172
eISSN - 1520-6041
pISSN - 0276-7333
DOI - 10.1021/acs.organomet.7b00632
Subject(s) - chemistry , ruthenium , carbon fibers , oxygen , medicinal chemistry , photochemistry , catalysis , organic chemistry , materials science , composite number , composite material
The isolable ruthenium(II) bis(dinitrogen) complex [Ru(H) 2 (N 2 ) 2 (PCy 3 ) 2 ] ( 1 ) reacts with aryl ethers (Ar-OR, R = Me and Ar) containing a ketone directing group to effect sp 2 C-O bond activation at temperatures below 40 °C. DFT studies support a low-energy Ru(II)/Ru(IV) pathway for C-O bond activation: oxidative addition of the C-O bond to Ru(II) occurs in an asynchronous manner with Ru-C bond formation preceding C-O bond breaking. Alternative pathways based on a Ru(0)/Ru(II) couple are competitive but less accessible due to the high energy of the Ru(0) precursors. Both experimentally and by DFT calculations, sp 2 C-H bond activation is shown to be more facile than sp 2 C-O bond activation. The kinetic preference for C-H bond activation over C-O activation is attributed to unfavorable approach of the C-O bond toward the metal in the selectivity determining step of the reaction pathway.