Boosting chiral nanoparticle responses Optical nanomaterials that combine chirality and magnetism are useful for magneto-optics and as chiral catalysts. Although chiral inorganic nanostructures can exhibit high circular dichroism, modulating this optical activity has usually required irreversible chemical changes. Yeom et al. synthesized paramagnetic cobalt oxide (Co3O4) nanoparticles with l- and d-cysteine surface ligands. These ligands created chiral distortions of the crystal lattices, and this anisotropy led to much stronger chiroptical activity. The circular dichroism in the ultraviolet of nanoparticle gels could be modulated with magnetic fields of ∼1.5 tesla. Science, this issue p. 309 Chiral amino acid ligands create lattice distortions that boost the chiroptical activity of cobalt oxide nanoparticles. Chiral inorganic nanostructures have high circular dichroism, but real-time control of their optical activity has so far been achieved only by irreversible chemical changes. Field modulation is a far more desirable path to chiroptical devices. We hypothesized that magnetic field modulation can be attained for chiral nanostructures with large contributions of the magnetic transition dipole moments to polarization rotation. We found that dispersions and gels of paramagnetic Co3O4 nanoparticles with chiral distortions of the crystal lattices exhibited chiroptical activity in the visible range that was 10 times as strong as that of nonparamagnetic nanoparticles of comparable size. Transparency of the nanoparticle gels to circularly polarized light beams in the ultraviolet range was reversibly modulated by magnetic fields. These phenomena were also observed for other nanoscale metal oxides with lattice distortions from imprinted amino acids and other chiral ligands. The large family of chiral ceramic nanostructures and gels can be pivotal for new technologies and knowledge at the nexus of chirality and magnetism.

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手磁性纳米粒子和凝胶

增强手性纳米粒子响应 结合手性和磁性的光学纳米材料可用于磁光和手性催化剂。虽然手性无机纳米结构可以表现出高圆二色性，但调节这种光学活性通常需要不可逆的化学变化。Yeom 等人。合成了具有 l-和 d-半胱氨酸表面配体的顺磁性氧化钴 (Co3O4) 纳米粒子。这些配体造成晶格的手性扭曲，而这种各向异性导致更强的手性活性。纳米粒子凝胶在紫外光中的圆二色性可以用~1.5 特斯拉的磁场进行调制。科学，这个问题 p。309 手性氨基酸配体产生晶格畸变，提高氧化钴纳米粒子的手性活性。手性无机纳米结构具有较高的圆二色性，但目前对其光学活性的实时控制只能通过不可逆的化学变化来实现。场调制是通向手性光学设备的更理想的路径。我们假设，对于磁跃迁偶极矩对极化旋转有很大贡献的手性纳米结构，可以获得磁场调制。我们发现，具有晶格手性畸变的顺磁性 Co3O4 纳米颗粒的分散体和凝胶在可见光范围内表现出手性光学活性，其强度是同等尺寸的非顺磁性纳米颗粒的 10 倍。纳米颗粒凝胶对紫外范围内圆偏振光束的透明度通过磁场可逆地调制。对于其他纳米级金属氧化物也观察到了这些现象，这些金属氧化物由于印迹氨基酸和其他手性配体而导致晶格畸变。手性陶瓷纳米结构和凝胶的大家族对于手性和磁性关系的新技术和知识至关重要。