1448366-44-6Relevant academic research and scientific papers
π Donation and its effects on the excited-state lifetimes of luminescent platinum(II) terpyridine complexes in solution
Hight, Lauren M.,McGuire, Meaghan C.,Zhang, Yu,Bork, Matthew A.,Fanwick, Phillip E.,Wasserman, Adam,McMillin, David R.
, p. 8476 - 8482 (2013)
Introducing electron-donating groups extends the excited-state lifetimes of platinum(II)-terpyridine complexes in fluid solution. Such systems are of interest for a variety of applications, viz., as DNA-binding agents or as components in luminescence-based devices, especially sensors. The complexes investigated here are of the form [Pt(4′-X-T)Y]+, where 4′-X-T denotes a 4′-substituted 2,2′:6′,2″- terpyridine ligand and Y denotes the coligand. The π-donating abilities of -X and -Y increase systematically in the orders -NHMe 2 a factor of 100, ranging from 24 μs for [Pt(4′-pyrr-T)CN] + to 0.24 μs for [Pt(4′-ma-T)Cl]+, where ma-T denotes 4′-(methylamino)-2,2′:6′,2″-terpyridine and pyrr-T denotes 4′-(pyrrolidin-1-yl)-2,2′:6′,2″- terpyridine. Analysis of experimental and computational results shows that introducing a simple amine group on the terpyridine and/or a π-donating coligand engenders the emitting state with intraligand charge-transfer (ILCT) and/or ligand-ligand charge-transfer (LLCT) character. The excited-state lifetime increases when the change in orbital parentage lowers the emission energy, suppresses quenching via d-d states, and encourages delocalization of the excitation onto the ligand(s). At some point, however, the energy is low enough that direct vibronic coupling to the ground-state surface becomes important, and the lifetime begins to decrease again.
