Luminescent platinum(II) complexes of quinoxaline-2,3-dithiolate
- Univ. of Rochester, NY (United States)
The synthesis, characterization, and photophysical properties of several Pt(II) complexes of quinoxaline-2,3-dithiolate (qdt) and 6,7-dimethylquinoxaline-2,3-dithiolate (dmqdt) are described. Specifically, (TBA){sub 2}[Pt(qdt){sub 2}], where TBA = tetra-n-butylammonium, Pt(COD)(qdt), where COD = 1,5-cyclooctadiene, and Pt(phen)(qdt), where phen = 1,10-phenanthroline, and their dmqdt analogs have been prepared and examined with respect to their photophysical properties. Highly structured emission from Pt(COD)(qdt) in frozen glass solution at 77 K has been detected, having a major vibrational progression of 1370 cm{sup {minus}1} corresponding to a C=C stretching frequency of the quinoxalinedithiolate backbone. Solution luminescence from (TBA){sub 2}[Pt(qdt){sub 2}] and Pt(phen)(qdt) has been detected with quantum yields, {Phi}{sub em}, of 10{sup {minus}5} and 10{sup {minus}3}, respectively, although the latter is highly sensitive to solvent effects. The complex Pt(phen)(qdt) possesses a low-energy ({lambda}{sub max} = 497 nm in CHCl{sub 3}) absorption band assigned to a charge-transfer-to-diimine transition which exhibits a high degree of negative solvatochromism. Cyclic voltammetry was conducted on each of the complexes in order to probe further the nature of the HOMO and LUMO. From a simple thermochemical analysis, an excited state reduction potential of 1.14 V (vs NHE) has been estimated for Pt(phen)(qdt).
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 75710
- Journal Information:
- Inorganic Chemistry, Vol. 34, Issue 8; Other Information: PBD: 12 Apr 1995
- Country of Publication:
- United States
- Language:
- English
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