Duroux Gautier, Robin Lucas, Liu Peizhao, Dols Emilie, Mendes Matheus De Souza Lima, Buffière Sonia, Pardieu Elodie, Scalabre Antoine, Buffeteau Thierry, Nlate Sylvain, Oda Reiko, Raju Maria Sara, Atzori Matteo, Train Cyrille, Rikken Geert L J A, Rosa Patrick, Hillard Elizabeth A, Pouget Emilie
Institut de Chimie et Biologie des Membranes et des Nanoobjets (CBMN), CNRS - Université Bordeaux - Bordeaux INP, UMR 5248, Allée St Hilaire, Bat B14, 33607, Pessac, France.
Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), CNRS UMR 5026, 87 avenue du Dr. A. Schweitzer, 33608, Pessac, France.
Nanoscale. 2023 Jul 20;15(28):12095-12104. doi: 10.1039/d3nr02670a.
Because the combination of chiral and magnetic properties is becoming more and more attractive for magneto-chiral phenomena, we here aim at exploring the induction of chirality to achiral magnetic molecules as a strategy for the preparation of magneto-chiral objects. To this end, we have associated free base- and metallo-porphyrins with silica nano helices, using a variety of elaboration methods, and have studied them mainly by electronic natural circular dichroism (NCD) and magnetic circular dichroism (MCD) spectroscopies. While electrostatic or covalent surface grafting uniformly yielded very low induced CD (ICD) for the four assayed porphyrins, a moderate response was observed when the porphyrins were incorporated into the interior of the double-walled helices, likely due to the association of the molecules with the chirally-organized gemini surfactant. A generally stronger, but more variable, ICD was observed when the molecules were drop casted onto the helices immobilised on a quartz plate, likely due to the different capacities of the porphyrins to aggregate into chiral assemblies. Electronic spectroscopy, electron microscopy and IR spectroscopy were used to interpret the patterns of aggregation and their influence on ICD and MCD. No enhancement of MCD was observed as a result of association with the nanohelices except in the case of the free base, 5,10,15,20-tetra-(4-sulfonatophenyl)porphyrin (TPPS). This nanocomposite demonstrated a large ICD in the Soret region and a large MCD in the Q-region due to J-aggregation. However, no induced MChD was observed, possibly due to the spectral mismatch between the ICD and MCD peaks.
由于手性和磁性的组合对于磁手性现象越来越具有吸引力，我们在此旨在探索将手性诱导到非手性磁性分子上，作为制备磁手性物体的一种策略。为此，我们使用多种制备方法将游离碱卟啉和金属卟啉与二氧化硅纳米螺旋相结合，并主要通过电子自然圆二色性（NCD）和磁圆二色性（MCD）光谱对它们进行了研究。虽然静电或共价表面接枝对四种被测卟啉均产生了非常低的诱导圆二色性（ICD），但当卟啉被掺入双壁螺旋内部时，观察到了适度的响应，这可能是由于分子与手性组织的双子表面活性剂缔合所致。当将分子滴铸到固定在石英板上的螺旋上时，观察到通常更强但更具变化性的ICD，这可能是由于卟啉聚集成手性组装体的能力不同。电子光谱、电子显微镜和红外光谱被用于解释聚集模式及其对ICD和MCD的影响。除了游离碱5,10,15,20-四-（4-磺基苯基）卟啉（TPPS）的情况外，未观察到与纳米螺旋缔合导致的MCD增强。由于J-聚集，这种纳米复合材料在Soret区域表现出大的ICD，在Q区域表现出大的MCD。然而，未观察到诱导磁圆二色性（MChD），这可能是由于ICD和MCD峰之间的光谱不匹配所致。
