title: Chirality Inversion of CdSe and CdS Quantum Dots without Changing the Stereochemistry of the Capping Ligand.
abstract: L-cysteine derivatives induce and modulate the optical activity of achiral cadmium selenide (CdSe) and cadmium sulfide (CdS) quantum dots (QDs). Remarkably, N-acetyl-L-cysteine-CdSe and L-homocysteine-CdSe as well as N-acetyl-L-cysteine-CdS and L-cysteine-CdS showed "mirror-image" circular dichroism (CD) spectra regardless of the diameter of the QDs. This is an example of the inversion of the CD signal of QDs by alteration of the ligand's structure, rather than inversion of the ligand's absolute configuration. Non-empirical quantum chemical simulations of the CD spectra were able to reproduce the experimentally observed sign patterns and demonstrate that the inversion of chirality originated from different binding arrangements of N-acetyl-L-cysteine and L-homocysteine-CdSe to the QD surface. These efforts may allow the prediction of the ligand-induced chiroptical activity of QDs by calculating the specific binding modes of the chiral capping ligands. Combined with the large pool of available chiral ligands, our work opens a robust approach to the rational design of chiral semiconducting nanomaterials.
authors.affiliation: Department of Chemistry, University of Wyoming , Laramie, Wyoming 82071, United States.
authors.forename: Jung Kyu
authors.initials: JK
authors.lastname: Choi
authors.affiliation: Department of Chemistry, University of Wyoming , Laramie, Wyoming 82071, United States.
authors.forename: Benjamin E
authors.initials: BE
authors.lastname: Haynie
authors.affiliation: Department of Chemistry, University of Wyoming , Laramie, Wyoming 82071, United States.
authors.forename: Urice
authors.initials: U
authors.lastname: Tohgha
authors.affiliation: Department of Chemistry, University of Wyoming , Laramie, Wyoming 82071, United States.
authors.forename: Levente
authors.initials: L
authors.lastname: Pap
authors.affiliation: Department of Chemistry, University of Wyoming , Laramie, Wyoming 82071, United States.
authors.forename: K Wade
authors.initials: KW
authors.lastname: Elliott
authors.affiliation: Department of Chemistry, University of Wyoming , Laramie, Wyoming 82071, United States.
authors.forename: Brian M
authors.initials: BM
authors.lastname: Leonard
authors.affiliation: Department of Chemistry and Biochemistry, Texas Christian University , Fort Worth, Texas 76129, United States.
authors.forename: Sergei V
authors.initials: SV
authors.lastname: Dzyuba
authors.affiliation: Department of Chemistry, University of Wyoming , Laramie, Wyoming 82071, United States.
authors.forename: Krisztina
authors.initials: K
authors.lastname: Varga
authors.affiliation: Department of Chemistry, University of Wyoming , Laramie, Wyoming 82071, United States.
authors.forename: Jan
authors.initials: J
authors.lastname: Kubelka
authors.affiliation: Underwood International College, Integrated Science & Engineering Division, Yonsei University , Seoul 03722, Republic of Korea.
authors.forename: Milan
authors.initials: M
authors.lastname: Balaz
keywords: chiral semiconductor nanocrystals; circular dichroism; density functional theory; ligand-induced optical activity; nanoparticles; quantum chemical simulations; quantum dots