Synthesis, Photophysics, and Optical Limiting of Platinum(II) 4'-Tolylterpyridyl Arylacetylide Complexes
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- 作者：Fengqi Guo ; Wenfang Sun ; Yao Liu ; and Kirk Schanze
- 刊名：Inorganic Chemistry
- 出版年：2005
- 出版时间：May 30, 2005
- 年：2005
- 卷：44
- 期：11
- 页码：4055 - 4065
- 全文大小：220K
- 年卷期：v.44,no.11(May 30, 2005)
- ISSN：1520-510X
文摘
A series of 4'-tolylterpyridyl platinum(II) complexes with different arylacetylide ligands, namely, phenylacetylide,4-bromophenylacetylide, 4-nitrophenylacetylide, 4-methoxyphenylacetylide, 4-dimethylaminophenylacetylide, 1-naphthylacetylide, and 3-quinolinylacetylide, were synthesized. Their photophysical properties, such as electronic absorptionspectra, emission characteristics at room temperature and 77 K, and transient difference absorption spectra, havebeen investigated. All of these complexes exhibit a metal-to-ligand charge-transfer (1MLCT) transition at ca. 420-430 nm in their electronic absorption spectra. For ttpy-Ph, ttpy-C6H4Br-4, ttpy-C6H4OCH3-4, ttpy-C6H4N(CH3)2-4,and ttpy-Np, an additional solvatochromic charge-transfer band appears at ca. 460-540 nm. This band is sensitiveto the para substituents on the phenylacetylide ligand and is tentatively assigned to a metal- or/and acetylide-to-terpyridyl charge-transfer transition (i.e., a 1MLCT or/and 1LLCT transition). All of the complexes exhibit room-temperature phosphorescence. The emission can be attributed to a 3MLCT state except for ttpy-C6H4NO2-4, forwhich the emission likely originates from an intraligand 3
,* state involving the nitrophenylacetylide ligand. Forttpy-C6H4OCH3-4, ttpy-C6H4N(CH3)2-4, and ttpy-Np, there probably is more than one low-energy state in closeenergy proximity, resulting in multiple exponential decays. In addition, the triplet transient absorption differencespectra of ttpy-Ph, ttpy-C6H4Br-4, ttpy-C6H4NO2-4, and ttpy-Quin exhibit moderately intense, broad absorption bandsin the visible region and extending into the near-IR region, which likely originate from the same excited state thatemits or from a state that is in equilibrium with the emitting state. It appears that the electron-rich arylacetylideligands, especially 4-methoxyphenylacetylide and 4-dimethylaminophenylacetylide, cause a decrease of the emissionefficiency and disappearance of the transient absorption. In contrast, the complexes that exhibit positive absorptionbands in the visible spectral region of the triplet transient difference absorption spectra show substantial opticallimiting for nanosecond laser pulses at 532 nm.
,* state involving the nitrophenylacetylide ligand. Forttpy-C6H4OCH3-4, ttpy-C6H4N(CH3)2-4, and ttpy-Np, there probably is more than one low-energy state in closeenergy proximity, resulting in multiple exponential decays. In addition, the triplet transient absorption differencespectra of ttpy-Ph, ttpy-C6H4Br-4, ttpy-C6H4NO2-4, and ttpy-Quin exhibit moderately intense, broad absorption bandsin the visible region and extending into the near-IR region, which likely originate from the same excited state thatemits or from a state that is in equilibrium with the emitting state. It appears that the electron-rich arylacetylideligands, especially 4-methoxyphenylacetylide and 4-dimethylaminophenylacetylide, cause a decrease of the emissionefficiency and disappearance of the transient absorption. In contrast, the complexes that exhibit positive absorptionbands in the visible spectral region of the triplet transient difference absorption spectra show substantial opticallimiting for nanosecond laser pulses at 532 nm.