Emissive Pd(II) thiosemicarbazones bearing anthracene: New complexes with unusual coordination mode

• Published in: Inorganic chemistry communications 2019-04, Vol.102, p.120-125
• Main Authors: Nguyen, Minh-Hai, Khuat, Thi-Thuy-Ha, Nguyen, Hung-Huy, Phung, Quan-Manh, Dinh, Thi-Hien
• Format: Article
• Language: English
• ISSN: 1387-7003; 1879-0259
• DOI: 10.1016/j.inoche.2019.02.028

New emissive Pd(II) complexes with anthracene-based thiosemicarbazones have been readily prepared in high yields. X-ray crystallographic analysis reveals that N(4)-substituted groups of thiosemicarbazone ligands exert marked effect on coordination mode of Pd(II) central ion. Rare asymmetric chelation based on monothiosemicarbazone is found with small N(4)-substituted groups such as methyl or ethyl. TD-DFT calculations partly support the preferential formation of this unusual arrangement. The complexes display ligand-centered fluorescence emission which is independent of the coordination modes of Pd(II). Four new Pd(II) complexes of anthracene-based thiosemicarbazones which are emissive were successfully prepared. X-ray crystallography reveals that size of N(4)-substituted groups has a remarkable effect on coordination mode of the central metal atom. [Display omitted] •Marked size effect of N(4)-substituted groups on coordination modes of anthracene-based complexes was analyzed by SC-XRD.•Solution behavior of asymmetric Pd(II) complexes based on monothiosemicarbazones was probed by 1H NMR spectroscopy•DFT calculations partly affirm the unusual coordination modes and clearly explain the emission nature of the complexes.