Single-molecule force spectroscopy of bimolecular reactions: system homology in the mechanical activation of ligand substitution reactions.
The mechanochemistry of the bimolecular nucleophilic substitution of DMSO for substituted pyridines at a square-planar pincer Pd(II) center was investigated using single-molecule force spectroscopy (SMFS). The SMFS data are interpreted in terms of the Bell-Evans model, which gives thermal off-rates for two reactions that agree well with previous, stress-free measurements. The characteristic force dependency of the rupture rate, fbeta, is effectively constant for the two reactions examined (22 +/- 2 and 24 +/- 2 pN), and the system homology in the mechanical response is consistent with expected similarities in the reaction potential energy surfaces.
Department of Chemistry and Center for Biologically Inspired Materials and Material Systems, Duke University, Durham, North Carolina 27708-0346, USA.
Farrell R
FR
Kersey
Wayne C
WC
Yount
Stephen L
SL
Craig