Copper(I) and copper(II) complexes possessing cross-linked imidazole-phenol ligands: structures and dioxygen reactivity.

Copper(I) and copper(II) complexes possessing cross-linked imidazole-phenol ligands: structures and dioxygen reactivity. Research Abstract Details 

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Copper(I) and copper(II) complexes possessing cross-linked imidazole-phenol ligands: structures and dioxygen reactivity. Abstract Text:

Kaliappan Kamaraj,Eunsuk Kim,Benedikt Galliker,Lev N Zakharov,Arnold L Rheingold,Andreas D ,Kenneth D Karlin,

Catalytic reduction of O2 to H2O, and coupling to membrane proton translocation, occurs at the heterobinuclear heme a3-CuB active site of cytochrome c oxidase. One of the CuB ligated histidines is cross-linked to a neighboring tyrosine (C-N bond; tyrosine C6 and histidine epsilon-nitrogen), and the protic residue of this cross-linked His-Tyr moiety is proposed to participate as both an electron and a proton donor in the catalytic dioxygen reduction event. To provide insight into the chemistry of such a moiety, we have synthesized and characterized tetra- and tridentate pyridylalkylamine chelate ligands {LN4OR and LN3OR (R = H or Me)}, which include an imidazole-phenol (or anisole) cross-link and their copper(I/II) complexes. [CuI(LN4OH)]B(C6F5)4 (1) reacts with dioxygen at -80 degrees C in THF, forming an unstable trans-mu-1,2-peroxodicopper(II)complex, which subsequently converts to a dimeric copper(II)-phenolate complex [{Cu(LN4O-)}2](B(C6F5)4)2 (5a). The close analogue [CuI(LN4OMe)]B(C6F5)4 (3) binds dioxygen reversibly at -80 degrees C in tetrahydrofuran. Stopped-flow kinetics of the reaction [CuI(LN3OH)]ClO4 (2) with O2 in CH2Cl2 indicate a steady formation of the purple dimeric product [{Cu(LN3O-)}2](ClO4)2 (5b), which has been analyzed in the temperature range from -40 to +20 degrees C, DeltaH = -9.6 (6) kJ mol-1, DeltaS = -168 (2) J mol-1 K-1 (k(-40 degrees C) = 1.05(4) x 106 and k(+20 degrees C) = 4.6(2) x 105 M-2 s-1). The X-ray crystal structures of 1, [CuII(LN3OH)(MeOH)(OClO3-)](ClO4) (4), 5a, and 5b are reported.

Copper(I) and copper(II) complexes possessing cross-linked imidazole-phenol ligands: structures and dioxygen reactivity. Publishing Authors By Initials

K Kamaraj,E Kim,B Galliker,LN Zakharov,AL Rheingold,AD ,KD Karlin,

For similar organic chemicals: phenols research abstracts see: organic chemicals: phenols research

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Copper(I) and copper(II) complexes possessing cross-linked imidazole-phenol ligands: structures and dioxygen reactivity. Journal Published:

PUBLICATION TYPE: Research Support, U.S. Gov't,

Journal: Journal of the American Chemical Society

VOLUME: 125

Page Numbers: 6028-9

Journal Abbreviation: J. Am. Chem. Soc.

ISSN: 0002-7863

DAY: 21

MONTH: May

YEAR: 2003

Copper(I) and copper(II) complexes possessing cross-linked imidazole-phenol ligands: structures and dioxygen reactivity. Information

Number of References:

LANGUAGE: eng

NlmUniqueID: 7503056

Copper(I) and copper(II) complexes possessing cross-linked imidazole-phenol ligands: structures and dioxygen reactivity. Keywords Mesh Terms:

KEYWORDS: Phenols

MESH TERMS: chemistry

Chemical & Substance for Abstract: Copper(I) and copper(II) complexes possessing cross-linked imidazole-phenol ligands: structures and dioxygen reactivity. Information

Substance Name: Electron Transport Complex IV

Registry Number: EC 1.9.3.1

Grant and Affiliation Information for Copper(I) and copper(II) complexes possessing cross-linked imidazole-phenol ligands: structures and dioxygen reactivity.

AFFILIATION: Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, USA.

Country: United States

AGENCY: United States NIGMS

GRANT: GM60353

ACRONYM: GM

MEDLINETA: J Am Chem Soc

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