Mild sp²Carbon–Oxygen Bond Activation by an Isolable Ruthenium(II) Bis(dinitrogen) Complex: Experiment and Theory

Abstract

The isolable ruthenium(II) bis(dinitrogen) complex [Ru(H)2(N2)2(PCy3)2] (1) reacts with aryl ethers (Ar–OR, R = Me and Ar) containing a ketone directing group to effect sp2C–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, sp2C–H bond activation is shown to be more facile than sp2C–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.

Measuring multiple17O–13CJ-couplings in naphthalaldehydic acid: a combined solid state NMR and density functional theory approach

“…5 More recently, initiatives on biomass utilization have employed homogeneous catalysis for the activation and functionalization of ether C-O sigma (s) bonds for F capture and remediation. 6 The high chemical specificity and ability to probe short range interactions enables solid state NMR to investigate the relationship between a negative O-centred nucleophile and a sp 2 hybridized electrophilic C centre. In this study solid naphthalaldehydic acid (1) and its 2 H-naphthalaldehydic acid (2) counterpart, depicted in Fig.…”

Tunable Binding of Dinitrogen to a Series of Heterobimetallic Hydride Complexes

“…Preparation of N 2 and H 2 Complexes of Ru---M Heterobimetallics. Reaction of [Ru(H) 2 (N 2 ) 2 (PCy 3 ) 2 ] (1) 12 with a series of the β-diketiminate stabilized hydrides of aluminum, zinc, and magnesium under an atmosphere of H 2 proceeded at 25 °C over the course of 24 h to generate the new heterobimetallic dihydrogen complexes M•Ru-H 2 (M = Al, Zn, Mg, Scheme 1). The new dihydrogen complexes are only stable under an atmosphere of H 2 , precluding their full characterization in the solid state.…”