lewcenko-simultaneouscontrol-2011.pdf (523.51 kB)
Simultaneous control of spectroscopic and electrochemical properties in functionalised electrochemiluminescent tris(2,2'-bipyridine)ruthenium(II) complexes
journal contribution
posted on 2011-01-01, 00:00 authored by Gregory Barbante, C Hogan, D Wilson, Naomi Anne Lewcenko, Fred PfefferFred Pfeffer, Neil BarnettNeil Barnett, Paul FrancisPaul FrancisUsing a combination of electrochemical, spectroscopic and computational techniques, we have explored the fundamental properties of a series of ruthenium diimine complexes designed for coupling with other molecules or surfaces for electrochemiluminescence (ECL) sensing applications. With appropriate choice of ligand functionality, it is possible to manipulate emission wavelengths while keeping the redox ability of the complex relatively constant. DFT calculations show that in the case of electron withdrawing substituents such as ester or amide, the excited state is located on the substituted bipyridine ligand whereas in the case of alkyl functionality it is localised on a bipyridine. The factors that dictate annihilation ECL efficiency are interrelated. For example, the same factors that determine ΔG for the annihilation reaction (i.e. the relative energies of the HOMO and LUMO) have a corresponding effect on the energy of the excited state product. As a result, most of the complexes populate the excited state with an efficiency (Φex) of close to 80% despite the relatively wide range of emission maxima. The quantum yield of emission (Φp) and the possibility of competing side reactions are found to be the main determinants of ECL intensity.
History
Journal
AnalystVolume
136Issue
7Pagination
1329 - 1338Publisher
Royal Society of ChemistryLocation
Cambridge, United KingdomPublisher DOI
ISSN
0003-2654eISSN
1364-5528Language
engPublication classification
C1 Refereed article in a scholarly journalCopyright notice
2011, Royal Society of ChemistryUsage metrics
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No categories selectedKeywords
Science & TechnologyPhysical SciencesChemistry, AnalyticalChemistryELECTRON-TRANSFER REACTIONSMOLECULAR-ORBITAL METHODSRUTHENIUM(II) POLYPYRIDYL COMPLEXESTRANSITION-METAL-COMPLEXESGAUSSIAN-BASIS SETSELECTROGENERATED CHEMILUMINESCENCEEXCITED-STATETEMPERATURE-DEPENDENCECHEMI-LUMINESCENCERU(II) COMPLEXES
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