FlowNMR spectroscopy is an excellent technique for non-invasive real-time reaction monitoring under relevant conditions that avoids many of the limitations that bedevil other reaction monitoring techniques.

A water-soluble boronate-based fluorescent probe was evaluated for the detection of peroxynitrite (ONOO À) in the presence of a monosaccharide. The enhanced fluorescence of the probe when bound with D-fructose was switched off in the presence of peroxynitrite. In contrast, other reactive oxygen/ nitrogen species (ROS/RNS) led to only slight fluorescence decreases due to protection by an internal N-B interaction. The interaction of the probe with D-fructose not only strengthens the fluorescence signal, but also protects the boronic acid from oxidation by other ROS/RNS. Therefore, under conditions generating various ROS/RNS, the boronate-based saccharide complex preferentially reacts with peroxynitrite. The probe was used in cell imaging experiments for the detection of endogenous and exogenous peroxynitrite. The sensor displays good "on-off" responses towards peroxynitrite, both in RAW 264.7 cells and HeLa cells.

Poly(mandelic acid) (PMA) is an aryl analogue of poly(lactic acid) (PLA) and a biodegradable analogue of polystyrene. The preparation of stereoregular PMA was realized using a pyridine/mandelic acid adduct (Py⋅MA) as an organocatalyst for the ring-opening polymerization (ROP) of the cyclic O-carboxyanhydride (manOCA). Polymers with a narrow polydispersity index and excellent molecular-weight control were prepared at ambient temperature. These highly isotactic chiral polymers exhibit an enhancement of the glass-transition temperature (T(g)) of 15 °C compared to the racemic polymer, suggesting potential future application as high-performance commodity and biomedical materials.

Reaction between a β-diketiminato magnesium hydride and carbon monoxide results in the isolation of a dimeric cis-enediolate species through the reductive coupling of two CO molecules. Under catalytic conditions with PhSiH3, an observable magnesium formyl species may be intercepted for the mild reductive cleavage of the CO triple bond.

The catalytic addition of phosphines to alkenes and alkynes is a very attractive process that offers access to phosphines in a 100% atom-economic reaction using readily available and inexpensive materials. The products are potentially useful ligands and organocatalysts. Herein we report the first example of intramolecular hydrophosphination of a series of non-activated phosphino-alkenes and phosphino-alkynes with a simple iron β-diketiminate complex. Kinetic studies suggest that this transformation is first order with respect to both the phosphine and the catalyst. A mechanistic interpretation of the iron-catalyzed hydrophosphination is presented, supported by the experimental evidence collected.

Through a dramatic advance in the coordination chemistry of the zinc-hydride bond, we describe the trajectory for the approach of this bond to transition metals. The dynamic reaction coordinate was interrogated through analysis of a series of solid state structures and is one in which the TM-H-Zn angle becomes increasingly acute as the TM-Zn distance decreases. Parallels may be drawn with the oxidative addition of boron-hydrogen and silicon-hydrogen bonds to transition metal centers.

Reaction of [Ru(PPh 3 ) 3 HCl] with LiCH 2 TMS, MgMe 2 , and ZnMe 2 proceeds with chloride abstraction and alkane elimination to form the biscyclometalated derivatives [Ru(PPh 3 )(C 6 H 4 PPh 2 ) 2 H][M′] where [M′] = [Li-(THF) 2 ] + (1), [MgMe(THF) 2 ] + (3), and [ZnMe] + (4), respectively. In the presence of 12-crown-4, the reaction with LiCH 2 TMS yields [Ru(PPh 3 )(C 6 H 4 PPh 2 ) 2 H][Li(12crown-4) 2 ] (2). These four complexes demonstrate increasing interaction between M′ and the hydride ligand in the [Ru(PPh 3 )(C 6 H 4 PPh 2 ) 2 H] − anion following the trend 2 (no interaction) < 1 < 3 < 4 both in the solid-state and solution. Zn species 4 is present as three isomers in solution including square-pyramidal [Ru-(PPh 3 ) 2 (C 6 H 4 PPh 2 )(ZnMe)] (5), that is formed via C−H reductive elimination and features unsaturated Ru and Zn centers and an axial Z-type [ZnMe] + ligand. A [ZnMe] + adduct of 5, [Ru(PPh 3 ) 2 (C 6 H 4 PPh 2 )(ZnMe) 2 ][BAr F 4 ] ( 6) can be trapped and structurally characterized. 4 reacts with H 2 at −40 °C to form [Ru(PPh 3 ) 3 (H) 3 (ZnMe)], 8-Zn, and contrasts the analogous reactions of 1, 2, and 3 that all require heating to 60 °C. This marked difference in reactivity reflects the ability of Zn to promote a rate-limiting C−H reductive elimination step, and calculations attribute this to a significant stabilization of 5 via Ru → Zn donation. 4 therefore acts as a latent source of 5 and this operational "dual unsaturation" highlights the ability of Zn to promote reductive elimination in these heterobimetallic systems. Calculations also highlight the ability of the heterobimetallic systems to stabilize developing protic character of the transferring hydrogen in the rate-limiting C−H reductive elimination transition states.

Catalytic hydrogen transfer from basic isopropyl alcohol to aryl ketones mediated by [(arene)­(TsDPEN)­RuCl] complexes has been investigated by operando 1H NMR spectroscopy using a recirculating flow setup. Selective excitation pulse sequences allowed fast and quantitative monitoring of the key [(mesitylene)­(TsDPEN)­RuH] intermediate during catalysis, which is shown to interact with both substrates by polarization transfer experiments. Comparison of reaction profiles with catalyst speciation traces in conjunction with reaction progress kinetic analysis using variable time normalization and kinetic modeling showed the existence of two independent catalyst deactivation/inhibition pathways: whereas excess base exerted a competitive inhibition effect on the unsaturated catalyst intermediate, the active hydride suffered from an inherent first-order decay that is not evident in early stages of the reaction where turnover is fast. Isotopic labeling revealed arene loss to be the entry point into deactivation pathways to Ru nanoparticles via hydride-bridged intermediates.