title: Hafnium(IV) chloride complexes with chelating β-ketiminate ligands: Synthesis, spectroscopic characterization and volatility study.
abstract: 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 ((1)H NMR, (13)C 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).
authors.affiliation: Department of Chemistry, Central Michigan University, Mount Pleasant, MI 48859, USA; Centre for Nano and Material Sciences, Jain University, Jain Global Campus, Bangalore 562112, Karnataka, India. Electronic address: p.siddappa@jainuniversity.ac.in.
authors.forename: Siddappa A
authors.initials: SA
authors.lastname: Patil
authors.affiliation: Department of Chemistry, Central Michigan University, Mount Pleasant, MI 48859, USA.
authors.forename: Phillip A
authors.initials: PA
authors.lastname: Medina
authors.affiliation: Department of Chemistry, Central Michigan University, Mount Pleasant, MI 48859, USA.
authors.forename: Aleks
authors.initials: A
authors.lastname: Antic
authors.affiliation: Department of Chemistry, University of California, Irvine, CA 92697, USA.
authors.forename: Joseph W
authors.initials: JW
authors.lastname: Ziller
authors.affiliation: Department of Chemistry, Saint Vincent College, 300 Fraser Purchase Road, Latrobe, PA 15650, USA.
authors.forename: Jason K
authors.initials: JK
authors.lastname: Vohs
authors.affiliation: Department of Chemistry, Central Michigan University, Mount Pleasant, MI 48859, USA. Electronic address: fahlm1b@cmich.edu.
authors.forename: Bradley D
authors.initials: BD
authors.lastname: Fahlman
keywords: Hafnium compounds; High-κ; MOCVD; Sublimation enthalpy; Volatility; β-Ketiminate