| Autor: |
López-López JC; University of Houston, Department of Chemistry, Lamar Fleming Jr. Building, 3585 Cullen Blvd. Room 112, Houston, Texas 77204-5003, United States.; Departamento de Química Inorgánica, Facultad de Química, Universidad de Murcia, Campus de Espinardo, Edificio 19, 30100 Murcia, Spain., Nguyen YH; University of Houston, Department of Chemistry, Lamar Fleming Jr. Building, 3585 Cullen Blvd. Room 112, Houston, Texas 77204-5003, United States., Jiang C; University of Houston, Department of Chemistry, Lamar Fleming Jr. Building, 3585 Cullen Blvd. Room 112, Houston, Texas 77204-5003, United States., Teets TS; University of Houston, Department of Chemistry, Lamar Fleming Jr. Building, 3585 Cullen Blvd. Room 112, Houston, Texas 77204-5003, United States. |
| Abstrakt: |
In this work, we present a series of luminescent platinum acetylide complexes with acetylides that are electronically modified and/or π-extended. Six isocyanide-supported complexes with the general formula cis -[Pt(CNAr) 2 (C≡CR) 2 ] and six acyclic diaminocarbene (ADC) complexes of the form trans -[Pt(ADC) 2 (C≡CR) 2 ], all using the same five acetylide ligands, are described. The compounds are characterized by multinuclear NMR, FT-IR, and single-crystal X-ray diffraction. In most cases, the phosphorescence arises from an acetylide-centered 3 (π → π*) excited state, although in one of the isocyanide compounds there is evidence for a charge-transfer excited state. The photoluminescence wavelength depends strongly on the substitution pattern and extent of the π conjugation on the acetylide, with maxima spanning the range of ca. 460-540 nm. Most photoluminescence lifetimes are long, beyond 50 μs, and quantum yields are low to moderate, 0.043-0.27. The photoluminescence quantum yields and lifetimes in these compounds do not systematically improve in the ADC complexes compared to the isocyanide versions, suggesting the neutral ligand σ-donor character does not play a large role in the excited-state dynamics when the triplet excited state is delocalized over a large π system. |
