Mechanism of intramolecular C-H bond activation in [(LCu) 2(μ-O)2]2+ (L = 1,4,7-trialkyl-1,4,7-triazacyclononane): Quantum mechanical/molecular mechanical modeling

Christopher J. Cramer; Christopher R. Kinsinger; Youngshang Pak

doi:10.1016/S0166-1280(03)00292-6

Mechanism of intramolecular C-H bond activation in [(LCu) ₂(μ-O)₂]²⁺ (L = 1,4,7-trialkyl-1,4,7-triazacyclononane): Quantum mechanical/molecular mechanical modeling

Christopher J. Cramer, Christopher R. Kinsinger, Youngshang Pak

Administration (CSENG)

Research output: Contribution to journal › Article › peer-review

17 Scopus citations

Abstract

N-dealkylation in [(LCu)₂(μ-O)₂]²⁺ (L = 1,4,7-tribenzyl-1,4,7-triazacyclononane) is predicted by quantum-mechanical/molecular-mechanical calculations using density functional theory to take place with the dioxocopper core in a bis(μ-oxo) geometry via a mechanism involving internal hydrogen atom transfer of an equatorially located benzylic H to an oxo oxygen atom. This step is followed by a very-low barrier hydroxyl group rebound to generate an aminal that is hydrolyzed to an aldehyde on aqueous workup. There is some polar character to the H atom-transfer transition state so that it is weakly sensitive to aromatic substitution. At 233 K, tunneling plays a significant role in the kinetics.

Original language	English (US)
Pages (from-to)	111-120
Number of pages	10
Journal	Journal of Molecular Structure: THEOCHEM
Volume	632
Issue number	1-3
DOIs	https://doi.org/10.1016/S0166-1280(03)00292-6
State	Published - Aug 1 2003

Bibliographical note

Funding Information:
We thank Don Truhlar and Bill Tolman for helpful discussions on the subjects of tunneling and bis(μ-oxo)dicopper complexes, respectively. This work was supported in part by the National Science Foundation (CHE-0203346).

Keywords

Binuclear copper complex
C-H bond activation
Hydrogen-atom transfer
Kinetic isotope effect
Oxygen activation
Tunneling

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Mechanism of intramolecular C-H bond activation in [(LCu) ₂(μ-O)₂]²⁺ (L = 1,4,7-trialkyl-1,4,7-triazacyclononane): Quantum mechanical/molecular mechanical modeling. / Cramer, Christopher J.; Kinsinger, Christopher R.; Pak, Youngshang.
In: Journal of Molecular Structure: THEOCHEM, Vol. 632, No. 1-3, 01.08.2003, p. 111-120.

Research output: Contribution to journal › Article › peer-review

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abstract = "N-dealkylation in [(LCu)2(μ-O)2]2+ (L = 1,4,7-tribenzyl-1,4,7-triazacyclononane) is predicted by quantum-mechanical/molecular-mechanical calculations using density functional theory to take place with the dioxocopper core in a bis(μ-oxo) geometry via a mechanism involving internal hydrogen atom transfer of an equatorially located benzylic H to an oxo oxygen atom. This step is followed by a very-low barrier hydroxyl group rebound to generate an aminal that is hydrolyzed to an aldehyde on aqueous workup. There is some polar character to the H atom-transfer transition state so that it is weakly sensitive to aromatic substitution. At 233 K, tunneling plays a significant role in the kinetics.",

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AB - N-dealkylation in [(LCu)2(μ-O)2]2+ (L = 1,4,7-tribenzyl-1,4,7-triazacyclononane) is predicted by quantum-mechanical/molecular-mechanical calculations using density functional theory to take place with the dioxocopper core in a bis(μ-oxo) geometry via a mechanism involving internal hydrogen atom transfer of an equatorially located benzylic H to an oxo oxygen atom. This step is followed by a very-low barrier hydroxyl group rebound to generate an aminal that is hydrolyzed to an aldehyde on aqueous workup. There is some polar character to the H atom-transfer transition state so that it is weakly sensitive to aromatic substitution. At 233 K, tunneling plays a significant role in the kinetics.

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