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

The synthesis and characterization of four new beta-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-onel-hafnium (4b), dichloro-bis[4-(4-methoxyphenylamido)pent-3-en-2-onel-hafnium (4c), and dichloro-bis[4-(4-chlorophenylamido)pent-3-en-2-onel-hafnium (4d) are reported. All the complexes (4a-d) were characterized by spectroscopic methods (H-1 NMR, C-13 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 p-ketiminate hafnium(IV) chloride complexes (4a-d). Sublimation enthalpies (Delta H-sub) were calculated from thermogravimetric analysis (TGA) data, which show that, the dependence of Delta H-sub on the molecular weight (4a-c) and inductive effects from chlorine (4d). (C) 2015 Elsevier B.V. All rights reserved.