Coordination Chemistry Reviews
208 (2000) 115–137
Platinum diimine complexes: towards a
molecular photochemical device
Muriel Hissler, James E. McGarrah, William B. Connick,
David K. Geiger, Scott D. Cummings, Richard Eisenberg *
Department of Chemistry, Uniersity of Rochester, Rochester, NY 14627 -0216, USA
Received 3 September 1999; accepted 15 December 1999
Contents
Abstract .................................................... 115
1. Introduction ............................................... 116
2. The platinum diimine chromophore .................................. 117
3. Platinum diimine bis(acetylide) complexes .............................. 119
4. Self-quenching of Pt(diimine) complexes ............................... 124
5. A molecular photochemical device based on the platinum diimine chromophore ........ 126
6. Dyads and triads ............................................ 128
7. Conclusions................................................ 133
Acknowledgements ............................................. 134
References .................................................. 134
Abstract
Complexes having the general formula PtX
2
(diimine) where X
2
=dithiolate, bis(acetylide)
and diimine =bipyridine, phenanthroline and derivatives have been investigated for potential
use as chromophores in the conversion of light-to-chemical energy. These complexes, like the
analogous X =CN systems, are luminescent in fluid solution. Previous studies of the
dithiolate derivatives reveal that they possess a charge transfer excited state involving a
mixed metal – dithiolate donor orbital and a *(diimine) acceptor function with excited state
properties including emission energies, lifetimes and redox potentials that are tunable by
ligand variation. The bis(acetylide) complexes are brightly luminescent in fluid solution, and
their excited state is shown to be MLCT in character, consistent with an earlier proposal.
Both sets of diimine complexes show evidence of self-quenching, and for Pt(phen)(CCPh)
2
,
weak excimer emission is observed. The mechanism of quenching has been probed through
www.elsevier.com/locate/ccr
* Corresponding author. Tel.: +1-716-2755573; fax: +1-716-4736889.
E-mail address: rse7@chem.rochester.edu (R. Eisenberg).
0010-8545/00/$ - see front matter © 2000 Elsevier Science S.A. All rights reserved.
PII:S0010-8545(00)00254-X