Department of Chemistry , University of Utah , 315 South 1400 East, Room 2020 , Salt Lake City , Utah 84112 , United States.
Department of Chemistry , National Taiwan University , Taipei , 10617 Taiwan , R.O.C.
J Am Chem Soc. 2019 Apr 3;141(13):5535-5543. doi: 10.1021/jacs.9b01368. Epub 2019 Mar 14.
A series of platinum(II) metallacycles were prepared via the coordination-driven self-assembly of a phenazine-cored dipyridyl donor with a 90° Pt(II) acceptor and various dicarboxylate donors in a 1:1:2 ratio. While the metallacycles display similar absorption profiles, they exhibit a trend of blue-shifted fluorescence emission with the decrease in the bite angles between the carboxylate building blocks. Comprehensive spectroscopic and dynamic studies as well as a computational approach were conducted, revealing that the difference in the degree of constraint imposed on the excited-state planarization of the phenazine core within these metallacycles results in their distinct photophysical behaviors. As such, a small initial difference in the dicarboxylate building blocks is amplified into distinct photophysical properties of the metallacycles, which is reminiscent of the efficient functional tuning observed in natural systems. In addition to the pre-assembly approach, the photophysical properties of a metallacycle can also be modulated using a post-assembly modification to the dicarboxylate building block, suggesting another strategy for functional tuning. This research illustrated the potential of coordination-driven self-assembly for the preparation of materials with precisely tailored functionalities at the molecular level.
通过 phenazine 核双吡啶供体与 90° Pt(II)受体以及各种二羧酸供体以 1:1:2 的比例进行配位驱动的自组装，制备了一系列铂（II）金属环。虽然金属环显示出相似的吸收谱，但它们表现出荧光发射蓝移的趋势，这与羧酸根基块之间的咬合角度减小有关。进行了综合的光谱和动态研究以及计算方法，结果表明，在这些金属环中，对 phenazine 核心的激发态平面化施加的约束程度的差异导致了它们不同的光物理行为。因此，二羧酸根基块的微小初始差异被放大为金属环的不同光物理性质，这让人联想到在自然系统中观察到的高效功能调谐。除了预组装方法外，还可以通过对二羧酸根基块进行后组装修饰来调节金属环的光物理性质，这表明了另一种功能调谐策略。这项研究说明了配位驱动自组装在分子水平上制备具有精确功能的材料的潜力。
