skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Synthesis and electrochemical and spectroscopic properties of a series of binuclear and trinuclear ruthenium and palladium complexes based on a new bridging ligand containing terpyridyl and catechol binding sites

Abstract

The ligand 4{prime}-(3,4-dimethoxyphenyl)-2,2{prime}:6{prime},2{double_prime}-terpyridine (L{sup 2}), containing a terpyridyl binding site and a masked catechol binding site, was prepared by a standard Kroehnke-type synthesis. From this the complexes [Ru(terpy)-(L{sup 2})][PF{sub 6}]{sub 2} (1) and [Ru(L{sup 2}){sub 2}][PF{sub 6}]{sub 2} (2), containing one and two dimethoxyphenyl substituents, were prepared: demethylation with BBr{sub 3} afforded [Ru(terpy)(H{sub 2}L{sup 1})][PF{sub 6}]{sub 2} (3) and [Ru(H{sub 2}L{sup 1}){sub 2}][PF{sub 6}]{sub 2} (4), respectively, which have one or two free catechol binding sites pendant from the [Ru(terpy){sub 2}]{sup 2+} core. Binuclear complexes (based on 3) and trinuclear complexes (based on 4) were then prepared by attachment of other metal fragments at the catechol sites. In [Ru(terpy)({mu}-L{sup 1})Ru(bipy){sub 2}][PF{sub 6}]{sub 3} (5) and [Ru({mu}-L{sup 1}){sub 2}(Ru(bipy){sub 2}){sub 2}][PF{sub 6}]{sub 4} (6) the pendant (Ru(bipy){sub 2}(O-O)){sup n+} sites (O-O = catecholate, n = 0; o-benzosemiquinone, n = 1; o-benzoquinone, n = 2) are redox active and may be reversibly interconverted between the three oxidation levels. In [Ru(terpy)({mu}-L{sup 1})Pd(bipy)][PF{sub 6}]{sub 2} (7), [Ru({mu}-L{sup 1}){sub 2}(Pd(bipy)){sub 2}][PF{sub 6}]{sub 2} (8), [Ru(terpy)({mu}-L{sup 1})Pd(4,4{prime}-{sup t}Bu{sub 2}-bipy)][PF{sub 6}]{sub 2} (9), and [Ru({mu}-L{sup 1}){sub 2}(Pd(4,4{prime}-{sup t}Bu{sub 2}-bipy)){sub 2}][PF{sub 6}]{sub 2} (10) the pendant (Pd(bipy)(catecholate)) fragments are known to be photocatalysts for production of {sup 1}O{submore » 2} in their own right. Electrochemical and UV/vis studies were performed on all complexes and consistently indicate the presence of interactions between the components in 5-10. The EPR spectrum of 6 (which contains two semiquinone radicals) shows that the two spins are coupled by an exchange interaction.« less

Authors:
; ; ;  [1]
  1. Univ. of Bristol (United Kingdom)
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
75711
Resource Type:
Journal Article
Journal Name:
Inorganic Chemistry
Additional Journal Information:
Journal Volume: 34; Journal Issue: 8; Other Information: PBD: 12 Apr 1995
Country of Publication:
United States
Language:
English
Subject:
40 CHEMISTRY; RUTHENIUM COMPLEXES; STRUCTURAL CHEMICAL ANALYSIS; PALLADIUM COMPLEXES; CHEMICAL PREPARATION; ELECTRON SPIN RESONANCE; ELECTROCHEMISTRY; ABSORPTION SPECTROSCOPY

Citation Formats

Whittle, B, Everest, N S, Howard, C, and Ward, M D. Synthesis and electrochemical and spectroscopic properties of a series of binuclear and trinuclear ruthenium and palladium complexes based on a new bridging ligand containing terpyridyl and catechol binding sites. United States: N. p., 1995. Web. doi:10.1021/ic00112a013.
Whittle, B, Everest, N S, Howard, C, & Ward, M D. Synthesis and electrochemical and spectroscopic properties of a series of binuclear and trinuclear ruthenium and palladium complexes based on a new bridging ligand containing terpyridyl and catechol binding sites. United States. https://doi.org/10.1021/ic00112a013
Whittle, B, Everest, N S, Howard, C, and Ward, M D. Wed . "Synthesis and electrochemical and spectroscopic properties of a series of binuclear and trinuclear ruthenium and palladium complexes based on a new bridging ligand containing terpyridyl and catechol binding sites". United States. https://doi.org/10.1021/ic00112a013.
@article{osti_75711,
title = {Synthesis and electrochemical and spectroscopic properties of a series of binuclear and trinuclear ruthenium and palladium complexes based on a new bridging ligand containing terpyridyl and catechol binding sites},
author = {Whittle, B and Everest, N S and Howard, C and Ward, M D},
abstractNote = {The ligand 4{prime}-(3,4-dimethoxyphenyl)-2,2{prime}:6{prime},2{double_prime}-terpyridine (L{sup 2}), containing a terpyridyl binding site and a masked catechol binding site, was prepared by a standard Kroehnke-type synthesis. From this the complexes [Ru(terpy)-(L{sup 2})][PF{sub 6}]{sub 2} (1) and [Ru(L{sup 2}){sub 2}][PF{sub 6}]{sub 2} (2), containing one and two dimethoxyphenyl substituents, were prepared: demethylation with BBr{sub 3} afforded [Ru(terpy)(H{sub 2}L{sup 1})][PF{sub 6}]{sub 2} (3) and [Ru(H{sub 2}L{sup 1}){sub 2}][PF{sub 6}]{sub 2} (4), respectively, which have one or two free catechol binding sites pendant from the [Ru(terpy){sub 2}]{sup 2+} core. Binuclear complexes (based on 3) and trinuclear complexes (based on 4) were then prepared by attachment of other metal fragments at the catechol sites. In [Ru(terpy)({mu}-L{sup 1})Ru(bipy){sub 2}][PF{sub 6}]{sub 3} (5) and [Ru({mu}-L{sup 1}){sub 2}(Ru(bipy){sub 2}){sub 2}][PF{sub 6}]{sub 4} (6) the pendant (Ru(bipy){sub 2}(O-O)){sup n+} sites (O-O = catecholate, n = 0; o-benzosemiquinone, n = 1; o-benzoquinone, n = 2) are redox active and may be reversibly interconverted between the three oxidation levels. In [Ru(terpy)({mu}-L{sup 1})Pd(bipy)][PF{sub 6}]{sub 2} (7), [Ru({mu}-L{sup 1}){sub 2}(Pd(bipy)){sub 2}][PF{sub 6}]{sub 2} (8), [Ru(terpy)({mu}-L{sup 1})Pd(4,4{prime}-{sup t}Bu{sub 2}-bipy)][PF{sub 6}]{sub 2} (9), and [Ru({mu}-L{sup 1}){sub 2}(Pd(4,4{prime}-{sup t}Bu{sub 2}-bipy)){sub 2}][PF{sub 6}]{sub 2} (10) the pendant (Pd(bipy)(catecholate)) fragments are known to be photocatalysts for production of {sup 1}O{sub 2} in their own right. Electrochemical and UV/vis studies were performed on all complexes and consistently indicate the presence of interactions between the components in 5-10. The EPR spectrum of 6 (which contains two semiquinone radicals) shows that the two spins are coupled by an exchange interaction.},
doi = {10.1021/ic00112a013},
url = {https://www.osti.gov/biblio/75711}, journal = {Inorganic Chemistry},
number = 8,
volume = 34,
place = {United States},
year = {1995},
month = {4}
}