Charge Transfer Surface-Enhanced Raman and Absorption Spectra of the Zwitterionic Form of Cysteine Adsorbed on M@Au₁₂ (M = Au, Ag, Pt, and Pd) Nanoclusters

Abstract

The effect of the core atom type of the M@Au 12 nanocluster (M = Au, Ag, Pt, and Pd) on the normal (NR) and charge-transfer surface-enhanced Raman spectroscopy (CT-SERS) of the zwitterion form of L-cysteine (ZWCYS) adsorbed on two different sites (D1 and D2) of the nanocluster is investigated separately in the gas phase and water. Because SERS requires the calculation of the absorption spectrum, the effect of the core atom type on the absorption spectrum of M@Au 12 and its complex with the ZWCYS has also been investigated. The vibrational bands that show the intensity enhancement in the CT-SERS of the ZWCYS interacting with the D1 site of M@Au 12 nanocluster in water are O�C�O asymmetric stretching (M = Au and Ag), NH 2 bending (M = Ag), S−H stretching (M = Ag, Pt, and Pd), CH 2 bending (M = Pt), and CH 2 symmetric stretching (M = Pt and Pd). The ZWCYS at the D 2 site of the M@Au 12 nanocluster in water exhibits intensity enhancement for O�C�O asymmetric stretching (M = Pt), NH 3 wagging (M = Au), and S−H stretching (M = Pd). The intensity of the vibrational bands of ZWCYS does not increase for M = Ag but decreases for O�C�O asymmetric stretching, S−H stretching, CH 2 symmetric stretching, CH 2 asymmetric stretching, and especially NH 2 symmetric stretching.

Theoretical Spectroscopic Study of Normal Raman and Charge Transfer Surface-Enhanced Raman Scattering (SERS) Spectra of the Adsorbed l- and d-Cysteine on the Chiral Au34 and Ag4@Au30 Nanoclusters: Chirality Discrimination

“…Notably, the dispersion-corrected version of the PBE functional (PBE-D3) with the same basis set was also used for the optimization of the complexes. There are different investigations in the literature related to the reliability of using the M06-L functional for the study of the interaction of biomolecules, such as amino acids and nucleotides with metal surfaces. ,− The interaction energy ( E int ) and adsorption energy ( E ad ) of the l - and d -CYS with the Au 34 and Ag 4 @Au 30 clusters in the complexes were calculated considering the basis set superposition error (BSSE) using different DFT functionals (PBE, PBE-D3 (Grimme’s dispersion corrected version of PBE), and M06-L functional) with the same basis set. Also, E int was calculated for the complexes of l - and d -CYS with the Au 34 cluster employing the M06-L functional and def2-TZVPP basis set instead of LANL2DZ for Au atoms to confirm the appropriacy of the LANL2DZ basis set for Au atoms.…”

“…The adsorption of CYS on gold nanoparticles, clusters, and, surfaces has been studied to provide insight into chiral molecular recognition phenomena that are fundamental for the design of enantioseparation methods and asymmetric catalysis. ,− From the theoretical point of view, most of these studies are related to the adsorption energies and adsorption modes of CYS on the gold structures. ,,,− Our research group have investigated the interaction of the four forms of cysteine (uncharged, cationic, anionic, and zwitterion) with the M @Au 12 ( M = Au, Ag, Pd, and Pt) cluster to model the type of the core metal on the interaction of different forms of cysteine with core–shell Au nanoparticles . In the other study, Farrokhpour et al calculated the charge transfer surface-enhanced Raman and absorption spectra of cysteine (zwitterionic form) adsorbed on M@Au 12 ( M = Au, Ag, Pd, and Pt) cluster to distinguish the change in the adsorption mode due to the change of core atom using the SERS technique …”

Synthesis of Os@ZIF-8 nanocomposites with enhanced peroxidase-like activity for detection of Hg2+

“…Pt and Au). 19 This enabled Os-based NPs to be peroxidase-like specific nanozymes with high enzymatic activity. However, for practical applications, an issue still needs to be addressed.…”