International Research Experience for Undergraduates

Kirsten Griffeths

2002 Participant

Griffeths

Synthesis of an Iridium (III) Bis-terpyridine Dyad

The ability to convert light into either chemical or electrical energy has been a major area of study, whether aimed at modeling natural systems (ie. photosynthesis) or creating synthetic devices. This conversion of energy has been achieved in the past using ruthenium containing dyads and triads. In these molecules, a chromophore absorbs a photon which and is promoted to its excited state. This allows the transfer of an electron from a donor to an acceptor site within the molecule, creating a photoinduced charge separated state.


Griffeths Diagram


However, when ruthenium is used in the central metal complex, a parasitic energy transfer occurs between the excited chromophore and central ruthenium complex. Therefore, a different metal must be used to prevent this undesired energy transfer. Due to its physical properties, including a highly energetic excited state the possible construction of unsymmetrical arrays and a relatively good ability to accept electron, iridium(III) was chosen as the metallic core of the dyads in this study. In addition, the macrocycle M30 was incorporated within the dyad since dimerization during the synthesis is sterically prohibited and interesting charge transfer properties may be observed.

In this synthesis, a one-pot Suzuki cross-coupling reaction will be used to join iridium portion of the molecule and the phenanthroline moiety.