Degenerate Pathways for Metallacycle Ring Inversions: A Common Phenomenon Consistent with the Principle of Microscopic Reversibility

Abstract

Competing degenerate pathways for ring inversion in organometallic complexes are proposed to be ubiquitous examples that adhere to the principle of microscopic reversibility. The NMR spectra for ring inversion of two chromium arene dicarbonyl pyridyl chelates ([Cr{η6-C6H5(CH2) n (2-Py-κN)}(CO)2]; 2-Py = 2-pyridyl, n = 2 (1), and 3 (2)) and a manganese cyclopentadienyl dicarbonyl methyl sulfide chelate ([Mn{η5-C5H4COC(SCH3)2(SCH3-κS)}(CO)2] (3)) were characterized via variable-temperature NMR spectroscopy and DFT theoretical calculations.

Acylation and deacylation mechanism and kinetics of penicillin G reaction with StreptomycesR61 DD‐peptidase

“…Rather, these stationary points are not minima or maxima on the free energy surface but are still treated as such to adhere to the Principle of Microscopic Reversibility on the electronic energy surface. [ 85 ] More discussion on this nuance is provided in the Supporting Information.…”

CO2 Capture by 2‐(Methylamino)pyridine Ligated Aluminum Alkyl Complexes

“…It is necessary to identify these structures on the free energy diagram to adhere to the Principle of Microscopic Reversibility. [66] 3D structures for intermediates 7a, 7b, 7c, and 7 are displayed in Figure S21. Intermediate 7a converts to 7b via rotation of the propanoate ligand along to Al-O axis.…”

A Highly Asymmetric Gold(III) η3‐Allyl Complex

“…It has been argued that such a process is not in violation of the principle of microscopic reversibility provided that there exists a degenerate alternative pathway, of opposite chirality but energetically degenerate to the first one (see Supporting Information). Burkey and co‐workers recently reported metallacycle ring inversions that were suggested to occur by chiral, degenerate pathways. Interestingly, the interconversion of the enantiomers 3 and 3′ by this pathway does not involve a C s symmetric intermediate or transition state which might be considered to arise from double bond decoordination and Au−C and C−C bond rotations.…”

“…Theprocess described in Scheme 2(red pathway) involves the interconversion of one enantiomer of 3 to its enantiomeric counterpart (3' ')via achiral pathway.Ithas been argued [9] that such ap rocess is not in violation of the principle of microscopic reversibility provided that there exists ad egenerate alternative pathway,o fo pposite chirality but energetically degenerate to the first one (see Supporting Information). Burkey and co-workers [10] recently reported metallacycle ring inversions that were suggested to occur by chiral, degenerate Scheme 1. Top: Generation of Au III h 1 -a nd h 3 -allyl complexes 2 and 3.B ottom:C rystallographicstructure determination of 2 (left).…”