Resonance Raman spectroscopic study of N-acetylamino saccharides in UV region

Monday, October 6, 2025

11:10 AM - 11:30 AM EDT

Location: Meeting Room #6

Presenting Author(s)

KH

Kosuke Hashimoto

University of Toyama
Toyama, Toyama, Japan

Non-Presenting Author(s)

FM

Fatima Matroodi

Elettra Synchrotron
Trieste, Friuli-Venezia Giulia, Italy
SM

Soh Morimatsu

Kindai University
Higashiosaka, Osaka, Japan

Project Lead(s)

BR

Barbara Rossi, PhD

Beamline scientist
Elettra Synchrotron
Trieste, Friuli-Venezia Giulia, Italy

Non-Presenting Author(s)

Yusuke Morisawa

Associate Professor
Kindai University
Higashi Osaka, Osaka, Japan
YO

Yukihiro OZAKI

Professor emeritus
Kwansei Gakuin University
Nishinomiya, Hyogo, Japan

Project Lead(s)

HS

Hidetoshi Sato

Professor
Kwansei Gakuin University
Sanda, Hyogo, Japan

In fifteen words or less, explain the significance of this contribution (Novel Aspect).: Combination of UVRR and ATR-FUV spectroscopies has a potential to reveal orbital geometry in biomolecules.

Abstract Text: The far- and deep-ultraviolet (FUV/DUV) regions (120–250 nm) include electronic transitions not only of π orbitals but also of σ orbitals. This study presents an analytical approach that integrates synchrotron-based ultraviolet resonance Raman (UVRR) spectroscopy with attenuated total reflection far-ultraviolet (ATR-FUV) spectroscopy to investigate N-acetylamino saccharides in aqueous solutions. We examined glucose, galactose, N-acetylglucosamine (GlcNAc), and N-acetylgalactosamine (GalNAc), focusing on their amide and pyranose structures. ATR-FUV spectra revealed a broad absorption band around 190 nm for GlcNAc and GalNAc due to π→π*, n→π*, and Rydberg transitions of the amide group. UVRR spectra obtained with excitation at 213, 226, and 250 nm showed selective enhancement of amide bands, suggesting resonance effects governed by orbital symmetry and spatial orientation, rather than by absorption intensity alone. Quantum chemical calculations indicated that the 190 nm absorption band includes multiple electronic transitions with distinct orbital geometries. Excitation at 213 nm enhanced a unique band at 1488 cm⁻¹ (cis-amide), indicative of resonance through a symmetric n→π* transition. In contrast, glucose and galactose exhibited only weak pre-resonance responses. These findings demonstrate that UVRR and ATR-FUV spectroscopy can elucidate the geometric features of localized σ and π orbitals of molecules in solution.