Raman spectral characterization of silver metal-based complexes of different benzimidazolium ligands

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Molecular and biomolecular spectroscopy, 2020-05, Vol.232, p.118162, Article 118162
• Main Authors: Ali, Saqib, Riaz, Ayesha, Nawaz, Haq, Majeed, Muhammad Irfan, Iqbal, Muhammad Adnan, Bhatti, Haq Nawaz, Rashid, Nosheen, Kashif, Muhammad, Tahir, Muhammad, Nasir, Saira, Ullah, Saif, Farooq, Sidra, Naseem, Ammara
• Format: Article
• Language: English
• Subjects: Mono-N-heterocyclic carbene ligands; Principal Component Analysis; Raman spectroscopy; Silver complexes
• ISSN: 1386-1425
• DOI: 10.1016/j.saa.2020.118162

In this study, Raman spectroscopy has been employed for the characterization of two structurally different monodentate N-heterocyclic carbene ligands (ligand-1 and ligand-2) and their respective complexes (complex-1 and complex-2). The Raman spectral features are found helpful for the confirmation of formation of complexes. The significant Raman spectral features are identified for benzimidazole ring with higher intensities in carbene complexes having more polarizability as compared to their ligands, providing the evidence for the formation of coordinate covalent bond. The successful complexation is further supported by using multivariate data analysis technique, Principal Component Analysis (PCA), which is found very helpful to highlight the variability of Raman spectral data of both ligands and their respective metal complexes from each other. Moreover, the coordination of carbene with Ag(I) is confirmed from the dominant spectral markers of higher intensities at 359 cm−1 in complex-1 and 338 cm−1 in complex-2. The effective and reliable characterization and confirmation of metal complexes indicates the potential of Raman spectroscopy for its use for the characterization of the organometallic complexes and other chemical products. [Display omitted] •Raman spectroscopy employed for the characterization of two different ligands and their respective co-ordinate complexes.•Raman spectral signatures observed for both Ag(I)-(NHCs) complexes were associated with their respective ligands.•Principal Component Analysis (PCA) is found very helpful to differentiate two ligands and complexes from each other.•Raman peaks with higher intensities in complexes are due to enhanced polarizability of benzimidazolium on complex formation.