Computational and Spectroscopic Studies of New Rhenium(I) Complexes Containing Pyridylimidazo[1,5-a]pyridine Ligands: Charge Transfer and Dual Emission by Fine-Tuning of Excited States
Computational and Spectroscopic Studies of New Rhenium(I) Complexes Containing Pyridylimidazo[1,5-a]pyridine Ligands: Charge Transfer and Dual Emission by Fine-Tuning of Excited States
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DOI：
10.1021/om701175z
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发表时间：
2008-03
期刊：
影响因子：
2.8
通讯作者：
L. Salassa;C. Garino;Andrea Albertino;G. Volpi;C. Nervi;R. Gobetto;K. Hardcastle
中科院分区：
文献类型：
--
作者：
L. Salassa;C. Garino;Andrea Albertino;G. Volpi;C. Nervi;R. Gobetto;K. Hardcastle
合成了三个新的Re（CO）3Cl配合物（ReL 1 − ReL 3），分别含有N，N-双齿配体1-（2-吡啶基）-3-苯基咪唑并[1，5-a]吡啶（L1）、1-（2-吡啶基）-3-（4-叔丁基苯基）咪唑并[1，5-a]吡啶（L2）和1-（2-吡啶基）-3-（4-二甲氨基苯基）咪唑并[1，5-a]吡啶（L3）。利用吸收光谱和发射光谱研究了L1−L3和ReL 1 − ReL 3的光物理性质。测定了ReL 3的X射线结构。用含时密度泛函（TDDFT）方法研究了配体和配合物的电子结构和激发态。配体L1和L2显示具有有限电荷转移特性（CT）的1π−π* 发射，而L3由于二甲氨基的存在而从具有较高CT特性的激发态发射。没有发射金属配体电荷转移（MLCT）状态被发现的双金属配合物。ReL 1和ReL 2虽然与它们的配体相似，但显示出以配体为中心的1π−π*/3π−π* 双发射;单重发射下降。
Three new Re(CO)3Cl complexes (ReL1−ReL3) containing the N,N-bidentate ligands 1-(2-pyridyl)-3-phenylimidazo[1,5-a]pyridine (L1), 1-(2-pyridyl)-3-(4-tert-butylphenyl)imidazo[1,5-a]pyridine (L2), and 1-(2-pyridyl)-3-(4-dimethylaminophenyl)imidazo[1,5-a]pyridine (L3) were synthetized and fully characterized. Photophysical properties of L1−L3 and ReL1−ReL3 were studied with absorption and emission spectroscopy. The X-ray structure of ReL3 was determined. Time-dependent DFT (TDDFT) calculations were performed in order to elucidate the electronic structures and the excited states of ligands and complexes. Ligands L1 and L2 show 1π−π* emission with limited charge-transfer character (CT), while L3 emits from an excited state with higher CT character due to the presence of a dimethylamino group. No emissive metal-to-ligand charge-transfer (MLCT) states are found for the rhenium complexes. ReL1 and ReL2, although similar to their ligands, display a ligand-centered 1π−π*/3π−π* dual emission; singlet emissions fall ...