Abstract
A strongly absorbing and significantly luminescing diimine ligand, N, N′-diphenyl-p-(benzyl-1,3,4-oxadiazole)-2,2′-bipyridine (DPO-bpy), incorporating π-conjugated oxadiazole linkage units and remote triphenylamine groups has been synthesized and characterized, as have the corresponding mononuclear metal complexes, fac-(DPO-bpy)Re(CO)3Cl and fac-(DPO-bpy)Mn(CO)3Br. The rhenium complex was structurally characterized via X-ray crystallography. The nature of the emitting state of each of the complexes was elucidated via transient DC photoconductivity (TDCP), a technique that reports on the sign and magnitude of the difference in dipole moments between the emissive state and ground state. The TDCP signal is negative for the Re complex and is consistent with emission from a metal-to-ligand charge-transfer state. On the other hand, the TDCP signals for the Mn complex and for the free ligand are positive, with the complex yielding the larger value. The TDCP results, as well as extended Hückel calculations, support an intraligand charge-transfer assignment for the emissive states of both the Mn complex and the free ligand, with the former displaying a significantly higher emission quantum yield.
Original language | English (US) |
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Pages (from-to) | 53-60 |
Number of pages | 8 |
Journal | Inorganica Chimica Acta |
Volume | 318 |
Issue number | 1-2 |
DOIs | |
State | Published - Jun 18 2001 |
Funding
We thank Professor F. Lewis for the use of the lifetime setup and Dr. Rajdeep Kalgutkar for help with these measurements. Financial support from Swiss National Science Foundation (postdoctoral fellowship for F.W.M.V.) and the Chemical Sciences, Geosciences and Biosciences Division, Office of Basic Energy Sciences, Office of Science US Department of Energy (Grant No. DE-FG02-87ER13808) is gratefully acknowledged.
Keywords
- Luminescence
- Photoconductivity
- Polypyridine complexes
- Rhenium complexes
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry
- Materials Chemistry