State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
J Phys Chem A. 2010 Mar 18;114(10):3418-22. doi: 10.1021/jp911597z.
In this work, the photophysical properties of coordination-driven self-assembled metallosupramolecular rhomboids with the donor ligands 1,2-bis(3-pyridyl)ethyne (3a) and 1,4-bis(3-pyridyl)-1,3-butadiyne (3b) are investigated by use of both spectroscopic experiments and quantum chemistry calculations. All the geometric conformations of the chair and boat conformers of 3a and 3b are fully optimized using density functional theory. The time-dependent density functional theory method was also used to study the excited-state properties of these self-assembled metallosupramolecular rhomboids. At the same time, steady-state absorption and fluorescence as well as the time-correlated single photon counting techniques are used to measure their various spectral properties. The fluorescence spectra of these self-assembled metallosupramolecular rhomboids are very wide and show an evident two-peak feature, which can be tuned by different excitation wavelengths. It has been demonstrated that the chair conformers of both 3a and 3b are formed preferentially over their boat conformers due to the close proximity of the chelated bisphosphine platinum groups. Moreover, an additional shoulder observed at 416 nm in the fluorescence spectra of 3b indicates the presence of minor amounts of the boat conformer of 3b. In addition, we have also demonstrated that lengthening the acetylene chain of the donor ligand component of these rhomboids results in a red-shifted and broadened absorption band for these metallosupramolecular rhomboids. Furthermore, the nature of the excited states for these metallosupramolecular rhomboids varies with the acetylene chain length of the donor ligands and with the different conformers.
在这项工作中，通过光谱实验和量子化学计算研究了具有给体配体 1,2-双(3-吡啶基)乙炔(3a)和 1,4-双(3-吡啶基)-1,3-丁二炔(3b)的配位驱动自组装金属超分子菱形的光物理性质。使用密度泛函理论对 3a 和 3b 的椅式和船式构象的所有几何构象进行了全优化。还使用含时密度泛函理论方法研究了这些自组装金属超分子菱形的激发态性质。同时，使用稳态吸收和荧光以及时间相关单光子计数技术测量它们的各种光谱性质。这些自组装金属超分子菱形的荧光光谱非常宽，并显示出明显的双峰特征，可以通过不同的激发波长进行调谐。已经证明，由于螯合双膦铂基团的接近，3a 和 3b 的椅式构象优先于其船式构象形成。此外，在 3b 的荧光光谱中观察到 416nm 处的附加肩峰表明 3b 的船式构象存在少量。此外，我们还证明，这些菱形的给体配体部分的乙炔链的延长导致这些金属超分子菱形的吸收带红移和变宽。此外，这些金属超分子菱形的激发态的性质随给体配体的乙炔链长度和不同构象而变化。
