Abstract:
Helicenes represent a class of fascinating π compounds with fused yet folded backbones. Despite their broad structural diversity, harnessing helicenes to develop well-defined materials is still a formidable challenge. Here we report the synthesis of crystalline porous helicene materials by exploring helicenes to synthesize covalent 2D lattices and layered π frameworks. Topology-directed polymerization of [6]helicenes and porphyrin creates 2D covalent networks with alternate helicene-porphyrin alignment along the x and y directions at a 1.5-nm interval and develops [6]helicene frameworks through reversed anti-AA stack along the z direction to form segregated [6]helicene and porphyrin columnar π arrays. Notably, this π configuration enables the frameworks to be highly red luminescent with benchmark quantum yields. The [6]helicene frameworks trigger effieicnt intra-framework singlet-to-singlet state energy transfer from [6]helicene to porphyrin and facilitate intermolecular triplet-to-triplet state energy transfer from frameworks to molecular oxygen to produce reactive oxygen species, harvesting a wide range of photons from ultraviolet to near-infrared regions for light emitting and photo-to-chemical conversion. This study introduces a new family of extended frameworks, laying the groundwork for exploring well-defined helicene materials with unprecedented structures and functions.
摘要:
Helicenes代表一类令人着迷的π化合物,具有融合但折叠的主链。尽管它们的结构多样性广泛,利用螺旋来开发定义明确的材料仍然是一个巨大的挑战。在这里,我们通过探索螺旋合成共价2D晶格和层状π框架来报告结晶多孔螺旋材料的合成。[6]螺旋和卟啉的拓扑定向聚合产生2D共价网络,沿x和y方向以1.5nm的间隔交替排列螺旋-卟啉,并通过反向反AA堆叠沿z方向形成[6]螺旋骨架,形成分离的[6]螺旋和卟啉柱状π阵列。值得注意的是,这种π配置使框架能够以基准量子产率高度红光发光。[6]Helicene骨架触发了从[6]Helicene到卟啉的框架内单重态能量转移,并促进了分子间三重态到三重态的能量转移,从骨架到分子氧产生活性氧,收集从紫外线到近红外区域的各种光子,用于发光和光化学转换。这项研究引入了一个新的扩展框架家族,为探索具有前所未有的结构和功能的定义明确的螺旋材料奠定基础。