Colloidal dispersion of chiral layered hydroxide salt (LHS) nanocrystals exhibiting chiroptical response

• Published in: Journal of sol-gel science and technology 2022-12, Vol.104 (3), p.580-587
• Main Authors: Tokudome, Yasuaki, Koyama, Akihiro, Murata, Hidenobu, Okada, Kenji, Nakahira, Atsushi, Nishimura, Shigenori, Takahashi, Masahide
• Format: Article
• Language: English
• Subjects: Alkalizing; Amino acids; Ceramics; Chemical synthesis; Chemistry and Materials Science; Chirality; colloids; Composites; Crystal growth; Dichroism; etc.; fibers; Functional materials; Glass; Inorganic Chemistry; Inorganic materials; Interlayers; Invited Paper: Nano-structured materials (particles; Materials Science; Nanocrystals; Nanomaterials; Nanotechnology; Natural Materials; Nickel; Optical and Electronic Materials; Phenylalanine; Propylene oxide; Sol-Gel Research in Japan
• ISSN: 0928-0707; 1573-4846
• DOI: 10.1007/s10971-022-05766-4

Chiral inorganic materials have attracted increasing attention in the fields such as catalysis, electronics, photonics, and sensing. A new class of functional materials with chirality is extensively explored. Herein, we demonstrate the synthesis of nanometric nickel layered hydroxide salt (Ni-LHS) modified with chiral amino acids, (D- or L-) phenylalanine (PHE). An alkalization reaction in a starting mixture of nickel-phenylalanine aqua complexes was induced by using propylene oxide, leading to intercalate and adsorb phenylalanine on the surface and into the interlayers of Ni-LHS in an in-situ manner. The chiral molecules also act as surface modifier to inhibit the extensive crystal growth and aggregation, to form Ni-LHS with a diameter of 2–3 nm in a state of stablly-suspended in a solvent. It was also found that Ni-LHS exhibit induced circular dichroism (ICD) in the spectral range of d-d transitions of Ni(II) metal centres. The layered nanomaterials with chiroptical response demonstrated here is a promising option as an advanced adsorbent for detection of molecules. Graphical abstract Highlights Synthesis of nanometric nickel layered hydroxide salt accommodating chiral amino acids is achieved. Epoxide-mediated alkalization reaction is adopted for the synthesis of the stable sol of the nano hydroxide. The material is found to exhibit induced circular dichroism (ICD) in visible light range.