Hafnium complexes with versatile β-diketiminate ligands: Synthesis, spectroscopic investigation and volatility study

• A series of β-diketiminate hafnium(IV) complexes prepared.
• All the complexes were characterized by spectroscopic methods.
• The solid state structure of 3c and 4a were examined by single crystal XRD.
• The thermal stability and volatility of the compounds were reported.

Synthesis and spectral investigation of four novel β-diketiminate hafnium(IV) chloride complexes cis-dichloro-bis(2,4-bis(phenylimino)pent-3-ene)-hafnium (4a), cis-dichloro-bis(2,4-bis(4-methylphenylimino)pent-3-ene)-hafnium (4b), cis-dichloro-bis(2,4-bis(4-methoxyphenylimino)pent-3-ene)-hafnium (4c) and cis-dichloro-bis(2,4-bis(4-chlorophenylimino)pent-3-ene)-hafnium (4d) are reported. All complexes (4a–d) were characterized by spectroscopic methods (1H NMR, 13C NMR and mass) and elemental analysis. The solid-state structure of compound 4a was further examined by single crystal X-ray diffraction. The X-ray structure of 4a reveals that the complex is monomeric with the hafnium center in a distorted octahedral geometry, and the chloride ligands are in a cis arrangement. The thermal stability and volatility of the compounds were probed by TGA/DSC tests demonstrating the potential utility of compounds (4a–d) as precursors for CVD/ALD thin film growth below 200 °C.

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