Modification of Excited State Behavior with Ligand Substitution in Ru(II),Rh(III) Bimetallic Supramolecular Complexes

The terminal ligand in [(Ph₂phen)₂Ru(dpp)RhCl₂(TL)](PF₆)₃ (Ph2phen = 4,7-diphenyl1,10-phenanthroline; dpp = 2,3-bis(2-pyridyl)pyrazine; TL = terminal ligand – a 4,4′-disubstituted-2,2′-bipyridine where the substituent was carbomethoxy (dcmbpy), hydrogen (bpy) or methyl (Me₂bpy)). The electron-withdrawing ability of the substituent was shown to increase the rate of chloride loss upon electrochemical reduction, facilitating catalytic water reduction. The electronic properties of the terminal ligand also impact the photophysical properties of the molecule. The excited state lifetime of the complex with a dcmbpy terminal ligand was 93 ns while the excited state lifetimes of the complexes with a bpy or Me₂bpy terminal ligand were 44 ns and 47 ns, respectively. Ligand substitution was shown to influence the photocatalytic water reduction activity of these complexes with the dcmbpy complex producing approximately twice the amount of hydrogen (62 ± 7 turnovers in 20 h) as the other two complexes.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Chemistry

Department dc:contributor.department

Chemistry

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2015

Author dc:creator

• Sayre, Hannah Joy

Chairs dc:contributor.committeechair

• Tanko, James M.
• Brewer, Karen J.

Committee members dc:contributor.committeemember

• Deck, Paul A.
• Morris, Amanda J.

• supramolecule
• photochemistry
• electron-withdrawing
• excited state lifetime
• water reduction

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Dc Identifier Other

vt_gsexam:5604

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/75150