Chiroptical Transitions of Enantiomeric Ligand‐Activated Nickel Oxides

Abstract

Ligand‐induced chirality in transition‐metal oxide (TMO) nanostructures have great potential for designing materials with tunable chiroptical effects. Herein, a facile strategy is reported to prepare chiroptical active nickel‐oxide hybrids combined with pH adjustment, and the redox treatment results in ligand transformation, which is attributable to multiple optical transitions in the TMO nanostructures. The theoretical calculation also explains the chiral origins based on their complex models based on empirical analysis. It is also shown that enantiomeric TMO nanoparticles can be used as chiral inducers for chiroptical sensitive polymerization. These results demonstrate that TMO nanostructures can provide rational control over photochemical synthesis and chiral transfer of inorganics nanoarchitecture chirality.

Histidine‐Mediated Synthesis of Chiral Cobalt Oxide Nanoparticles for Enantiomeric Discrimination and Quantification

“…This behavior can be explained considering the role of NaBH 4 as a basifying agent because pH above 8 is needed to deprotonate the amine groups of aminoacids and favour its coordination with cobalt. [12] In fact, the use of NaOH as an alternative to NaBH 4 as a basic agent gave rise to similar results (Figure S5, Supporting Information), while under neutral conditions, the reaction yield was very low (low absorbance). Nevertheless, the XPS analysis of Co 3 O 4 NPs revealed that the Co 2+ /Co 3+ ratio increased with the NaBH 4 concentration from 0.85 to 0.99 (Figure S6 and Table S2, Supporting Information).…”

“…[4][5][6][7][8][9][10] Alternatively, the chirality transfer from chiral surface ligands to the inorganic nanostructure has also been proposed as one main route for producing NPs with chiroptical properties. [11][12][13] In comparison to noble metal nanomaterials (e.g., Au and Ag), [14,15] chiral transition metal oxide nanoparticles (CTMOs), such as Cu x OS@ZIF-8, [16] ZnO, [17] MoO 3−x , [18] WO 3−x , [19] or TiO 2 , [20] could show intense optical transitions from UV to near-infrared (NIR) that can be ascribed to charge transfer, plasmonic, and polaronic electronic transitions. [2] Thus, the dominant electronic transitions are responsible for the chiroptical properties.…”

Tunable optical activities in chiral transition metal oxide nanoparticles

“…20 Very recently, we prepared pH sensitive chiral nickel oxide NPs, which can be employed as chiral inducers to fabricate chiral polymers in the visible range. 21…”

“…As a newly flourishing field, chiral TMO NPs are promising in various applications, such as sensing and detection, biological-tissue-based therapy and chiral inducers. [19][20][21] For example, Xu et al developed an ultrasensitive probe for the detection of H 2 S in living cells based on chiral Cu x OS@ZIF-8 NPs, revealing a detection limit of up to 0.8 nmol per 10 6 cells for circular dichroism (CD). 19 It was demonstrated that nonstoichiometric chiral MoO 3−x NPs can be used as dual-mode photothermal therapy agents for cancer treatments, as a result of chiral selectivity for incident light.…”

“…20 Very recently, we prepared pH sensitive chiral nickel oxide NPs, which can be employed as chiral inducers to fabricate chiral polymers in the visible range. 21 It is worth noting that some achiral TMOs exhibit effective second harmonic generation (SHG) signals. For example, as a result of the non-centrosymmetric crystal structure, ZnO with a hexagonal wurtzite phase exhibits an efficient SHG effect.…”