Multiple-state emission from platinum(II) diimine dithiolate complexes. Solvent and temperature effects

Journal Article · Wed Apr 15 04:00:00 EDT 1992 · Inorganic Chemistry; (United States)

DOI:https://doi.org/10.1021/ic00034a009· OSTI ID:6915929

Zuleta, J A; Bevilacqua, J M; Eisenberg, R ^[1]; Rehm, J M ^[2]

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1. Univ. of Rochester, NY (United States)
2. Eastman Kodak Co., Rochester, NY (United States)

The solvent and temperature dependence of the emission of Pt(diimine)(dithiolate) complexes is reported where diimine = 4,4[prime]-dimethyl-2,2[prime]-bipyridine (dmbpy) or 4,7-diphenyl-1,10-phenanthroline (dpphen) and dithiolate = 1-(ethoxycarbonyl)-1-cyanoethylene-2,2-dithiolate (ecda) or 1-(tert-butoxycarbonyl)-1-cyanoethylene-2,2-dithiolate (tbcda). In fluid solution at room temperature, a single emission band is observed at [approximately] 16,670 cm[sup [minus]1] (600 nm) for the complexes Pt(dmbpy)(ecda) (1), Pt-(dpphen)(ecda) (2), and Pt(dpphen)(tbcda) (3), which are studied in detail. The radiative quantum yields and lifetimes of the emission decrease with increasing solvent polarity for the three complexes. In DMF/CH[sub 2]Cl[sub 2]/MeOH the emission intensity for the complexes increases between 298 and 175 K with no change in the emission energy. Between 175 and 165 K the emission undergoes a red shift to [approximately] 15,625 cm[sup [minus]1] (640 nm), corresponding to a rigidochromic effect, and below 140 K two new bands appear at higher energies (17,000-18,500 and 18,600-19,900 cm[sup [minus]1]). The latter bands have a relative separation of 1,360 cm[sup [minus]1] and are assigned to a [pi]-[pi]* diimine transition on the basis of their observed lifetime and comparison with PtCl[sub 2](diimine) analogues. Between 80 and 6 K, the lifetime of the 15,625-cm[sup [minus]1] (640-nm) emission band increases, while, below 50 K, its emission intensity decreases with decreasing temperature, suggesting the presence of closely spaced excited states. From a kinetic analysis of the radiative quantum yield and lifetime data, the low-energy emission is assigned to a charge-transfer manifold of two emitting states separated by 50-60 cm[sup [minus]1].

• OSTI ID: 6915929
• Journal Information: Inorganic Chemistry; (United States), Journal Name: Inorganic Chemistry; (United States) Vol. 31:8; ISSN 0020-1669; ISSN INOCAJ
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ABSORPTION SPECTRA
CHARGE TRANSPORT
COMPLEXES
EMISSION
ENERGY-LEVEL TRANSITIONS
HALOGEN COMPOUNDS
HYDRIODIC ACID
HYDROGEN COMPOUNDS
IMINES
INFRARED SPECTRA
INORGANIC ACIDS
IODINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PLATINUM COMPLEXES
SOLVENT PROPERTIES
SPECTRA
TEMPERATURE EFFECTS
TEMPERATURE RANGE
TEMPERATURE RANGE 0013-0065 K
TEMPERATURE RANGE 0065-0273 K
THIOLS
TRANSITION ELEMENT COMPLEXES