Fluorescent phenoxy benzoxazole complexes of zirconium and hafnium: synthesis, structure and photo-physical behaviour

• Published in: Dalton transactions : an international journal of inorganic chemistry Vol. 47; no. 32; pp. 11245 - 11252
• Main Authors: Kuhlmann, Lisa, Methling, Rafael, Simon, Jasmin, Neumann, Beate, Stammler, Hans-Georg, Strassert, Cristian A, Mitzel, Norbert W
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 2018
• Subjects: Coordination compounds; Fluorescence; Hafnium; Ligands; NMR spectroscopy; X-ray diffraction; Zirconium
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/c8dt01757c

A series of ten heteroleptic and homoleptic mononuclear Zr(iv) and Hf(iv) complexes bearing differently substituted phenoxy-benzoxazole ligands was synthesised. The complexes were characterised by 1H and 13C{1H} NMR spectroscopy as well as by elemental analyses and X-ray diffraction experiments. The molecular structures show octahedral or tetragonal-antiprismatic coordination motifs at the metal atom. The crystal packing patterns depend on the substitution of the ligands. The intermolecular interactions in the solid state are governed by weak π-π interactions, and are also dependent on the ligand structure. Photo-physical investigations reveal that all ten complexes show a ligand-centered fluorescence with emission maxima in the blue region of the electromagnetic spectrum.