The transition state of metal carboxylate mediated C–H activation is associated with carbon–metal bond formation supported by electron-poor carboxylates.
Accurate bond dissociation energies for large molecules are difficult to obtain by either experimental or computational methods. The former methods are hampered by a range of physical and practical limitations in gas-phase measurement techniques, while the latter require incorporation of multiple approximations whose impact on accuracy may not always be clear. When internal benchmarks are not available, one hopes that experiment and theory can mutually support each other. A recent report found, however, a large discrepancy between gas-phase bond dissociation energies, measured mass spectrometrically, and the corresponding quantities computed using density functional theory (DFT)-D3 and DLPNO-CCSD(T) methods. With the widespread application of these computational methods to large molecular systems, the discrepancy needs to be resolved. We report a series of experimental studies that validate the mass spectrometric methods from small to large ions and find that bond dissociation energies extracted from threshold collision-induced dissociation experiments on large ions do indeed behave correctly. The implications for the computational studies are discussed.
Cryogenic ion vibrational predissociation (CIVP) spectroscopy of a gas-phase molecular torsion balance to probe London dispersion forces in large molecules.
Copper(II) acetate is frequently used as a catalyst for bondforming reactions in organic synthesis. Unlike aqueous solutions, in which complete heterolysis to CuOAc + (aq) and AcO -(aq) prevails at low concentrations, it is clear that copper(II) acetate shows a large degree of aggregation in typical organic solvents. Here, the speciation behavior of Cu(OAc) 2 in organic solvents is probed by electrospray ionization mass spectrometry (ESI-MS), which reveals an extensive clustering of copper acetate species to form ions of the general composition [Cu n (X) 2n-1 ] + and [Cu n (X) 2n+1 ] -(X = OAc and [a]
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.