X-ray single crystal, DFT, IR and Raman study of 4,5-bis(N,N-di(2-hydroxyethyl)iminomethyl)acridine (BHIA)

• Intermolecular H-bonds in the BHIA crystal are the cause of the molecular symmetry distortion.
• BHIA IR spectra assignment indicates the bands of vibrations with the considerable participation of chelate fragment atoms.
• BHIA Raman spectrum is formed mainly from the aromatic fragment fundamental modes.

A new acridine derivative, 4,5-bis(N,N-di(2-hydroxyethyl)iminomethyl)acridine (BHIA), having high selective characteristics of the quantum fluorescence yield towards cadmium cations is studied in this work by X-ray single crystal and vibrational spectroscopy methods. X-ray single crystal analysis revealed that aliphatic substitutes joined to the acridine fragment in BHIA molecule are asymmetric. Non-equivalence of their hydroxyethyl groups occurs due to formation of intermolecular hydrogen bonds. To carry out the assignment of IR and Raman spectra of BHIA the calculations of optimized geometries and vibrational spectra are made on the basis of the density functional theory (DFT). The calculated geometrical parameters and vibrational spectra are in agreement with the experimental data. The assignment performed for 400–1800 cm−1 region shows that the vibrations from all fragments of BHIA molecule are presented in the IR spectrum while the vibrations with only main contribution of acridine fragment are observed in the Raman spectrum. Based on the analysis of the normal vibrations forms the most sensitive to complexation bands in the IR spectrum are predicted.