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Spectroscopic definition of electronic structure contributions to oxygen and nitrous oxide activation by mononuclear, binuclear, and tetranuclear copper sites in biology

Record Type:	Electronic resources : Monograph/item
Title/Author:	Spectroscopic definition of electronic structure contributions to oxygen and nitrous oxide activation by mononuclear, binuclear, and tetranuclear copper sites in biology
Author:	Chen, Peng.
Description:	385 p.
Notes:	Adviser: Edward I. Solomon.
Notes:	Source: Dissertation Abstracts International, Volume: 64-11, Section: B, page: 5515.
Contained By:	Dissertation Abstracts International64-11B.
Subject:	Chemistry, Inorganic.
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3111701
ISBN:	0496592319

Spectroscopic definition of electronic structure contributions to oxygen and nitrous oxide activation by mononuclear, binuclear, and tetranuclear copper sites in biology
Chen, Peng.

Spectroscopic definition of electronic structure contributions to oxygen and nitrous oxide activation by mononuclear, binuclear, and tetranuclear copper sites in biology [electronic resource] - 385 p.

Adviser: Edward I. Solomon.

Thesis (Ph.D.)--Stanford University, 2004.

Copper proteins play important roles in O2 and N2O activation in biology. Spectroscopic techniques and density functional calculations were combined to study the structure/function correlations of biological copper active sites and related model complexes involved in O2/N 2O activation to gain insight into their electronic structure contributions to reactivity. Three major systems were studied. (1) Side-on and end-on disulfide Cu2(S2) complexes in comparison with their peroxide Cu2(O2) analogues in the context of coupled binuclear copper proteins. The side-on CuII-disulfide/peroxide bonding interactions involve ligand pi*sigma donation and sigma* backbonding while the end-on Cu II-disulfide/peroxide complexes only have pi* sigma donor interactions. Their different metal-ligand bonding interactions result in differences in ligand activation. Frontier molecular orbital theory was then applied to the developed electronic structure descriptions of Cu n-O2 species to gain insight into their reactivity in electrophilic and H-atom abstraction reactions. (2) Mononuclear CuII-OOR(H) and CuII-superoxide complexes in the context of non-coupled binuclear copper sites in peptidylglycine alpha-hydroxylating monooxygenase (PHM) and dopamine beta-monooxygenase (DbetaM), and the PHM protein. The CuII-OOH species was found not very reactive for H-atom abstraction reaction. The side-on CuII-superoxide complex has a covalently delocalized ground state and can not be described as antiferromagnetic coupled system as previously considered. These model studies were then extended to define the electronic and geometric structure of the non-coupled binuclear copper sites and the putative CuIIM(His)2(Met)-OOH intermediate in PHM. The CuIIM-OOH species was also found non-reactive in H-atom abstraction reaction. (3) The mu 4-sulfide bridged tetranuclear CuZ center in N2O reductase. The resting CuZ center is an S = ½ system with 1CuII/3CuI configuration. The single spin of the cluster is partially delocalized with CuI being dominantly oxidized. The bridging sulfide forms an superexchange pathway between Cu I and CuII. Further reduction of the resting form gives the all-reduced 4CuI form of CuZ, which is active for N2O reduction. The developed electronic structure description provides a strategy for this CuZ center to overcome the reaction barrier of N2O reduction by a simultaneous 2e- transfer in a mu-1,3 bridged binding mode. Together these studies provide insight into electronic structure contributions to O2 and N2O activation by biological copper sites.

ISBN: 0496592319Subjects--Topical Terms:

197298
Chemistry, Inorganic.

Spectroscopic definition of electronic structure contributions to oxygen and nitrous oxide activation by mononuclear, binuclear, and tetranuclear copper sites in biology
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520 # $a Copper proteins play important roles in O2 and N2O activation in biology. Spectroscopic techniques and density functional calculations were combined to study the structure/function correlations of biological copper active sites and related model complexes involved in O2/N 2O activation to gain insight into their electronic structure contributions to reactivity. Three major systems were studied. (1) Side-on and end-on disulfide Cu2(S2) complexes in comparison with their peroxide Cu2(O2) analogues in the context of coupled binuclear copper proteins. The side-on CuII-disulfide/peroxide bonding interactions involve ligand pi*sigma donation and sigma* backbonding while the end-on Cu II-disulfide/peroxide complexes only have pi* sigma donor interactions. Their different metal-ligand bonding interactions result in differences in ligand activation. Frontier molecular orbital theory was then applied to the developed electronic structure descriptions of Cu n-O2 species to gain insight into their reactivity in electrophilic and H-atom abstraction reactions. (2) Mononuclear CuII-OOR(H) and CuII-superoxide complexes in the context of non-coupled binuclear copper sites in peptidylglycine alpha-hydroxylating monooxygenase (PHM) and dopamine beta-monooxygenase (DbetaM), and the PHM protein. The CuII-OOH species was found not very reactive for H-atom abstraction reaction. The side-on CuII-superoxide complex has a covalently delocalized ground state and can not be described as antiferromagnetic coupled system as previously considered. These model studies were then extended to define the electronic and geometric structure of the non-coupled binuclear copper sites and the putative CuIIM(His)2(Met)-OOH intermediate in PHM. The CuIIM-OOH species was also found non-reactive in H-atom abstraction reaction. (3) The mu 4-sulfide bridged tetranuclear CuZ center in N2O reductase. The resting CuZ center is an S = ½ system with 1CuII/3CuI configuration. The single spin of the cluster is partially delocalized with CuI being dominantly oxidized. The bridging sulfide forms an superexchange pathway between Cu I and CuII. Further reduction of the resting form gives the all-reduced 4CuI form of CuZ, which is active for N2O reduction. The developed electronic structure description provides a strategy for this CuZ center to overcome the reaction barrier of N2O reduction by a simultaneous 2e- transfer in a mu-1,3 bridged binding mode. Together these studies provide insight into electronic structure contributions to O2 and N2O activation by biological copper sites.
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