Hafnium(IV) chloride complexes with chelating β-ketiminate ligands: Synthesis, spectroscopic characterization and volatility study

• Four new hafnium complexes were prepared.
• All compounds were characterized by spectroanalytical methods.
• Structure of compound 4c was established by single-crystal XRD technique.
• Volatile trends of the complexes have been established.

The synthesis and characterization of four new β-ketiminate hafnium(IV) chloride complexes dichloro-bis[4-(phenylamido)pent-3-en-2-one]-hafnium (4a), dichloro-bis[4-(4-methylphenylamido)pent-3-en-2-one]-hafnium (4b), dichloro-bis[4-(4-methoxyphenylamido)pent-3-en-2-one]-hafnium (4c), and dichloro-bis[4-(4-chlorophenylamido)pent-3-en-2-one]-hafnium (4d) are reported. All the complexes (4a–d) were characterized by spectroscopic methods (1H NMR, 13C NMR, IR), and elemental analysis while the compound 4c was further examined by single-crystal X-ray diffraction, revealing that the complex is monomer with the hafnium center in octahedral coordination environment and oxygens of the chelating N–O ligands are trans to each other and the chloride ligands are in a cis arrangement. Volatile trends are established for four new β-ketiminate hafnium(IV) chloride complexes (4a–d). Sublimation enthalpies (ΔHsub) were calculated from thermogravimetric analysis (TGA) data, which show that, the dependence of ΔHsub on the molecular weight (4a–c) and inductive effects from chlorine (4d).

Four new β-ketiminate hafnium(IV) chloride complexes were synthesized and characterized. Volatile trends are established for four new β-ketiminate hafnium(IV) chloride complexes. Based on the low heats of enthalpy, high volatility is expected.Figure optionsDownload as PowerPoint slide