Volatile iridium(I) complexes with β-diketones and cyclooctadiene: syntheses, structures and thermal properties

<p>A series of volatile mixed-ligand iridium(I) complexes [Ir(cod)(L)] (cod = cyclooctadiene-1,5, L = R¹C(O)CHC(O)R², R¹ = CF₃, R² = CF₃ – hfac <b>1</b>, Me – tfac <b>2</b>; ^<i>t</i>Bu – ptac <b>3</b>, Ph – btfac <b>4</b>, R¹ = R² = Me – acac <b>5</b>; ^<i>t</i>Bu – thd <b>6</b>) was synthesized and investigated in terms of usage in metal-organic chemical vapor deposition processes. Compounds <b>3</b> and <b>4</b> were obtained for the first time. All compounds were investigated by elemental analysis, NMR spectroscopy, thermogravimetry, and mass spectrometry. Crystal structures of <b>2</b>–<b>4</b> and <b>6</b> were determined by single-crystal XRD. The influence of β-diketonate ligand on the thermal properties of complexes in condensed and gas phase was revealed. The following volatility order was arranged: L = hfac <b>1</b> > tfac <b>2</b> ≈ ptac <b>3</b> > acac <b>5</b> > thd <b>6</b> > btfac <b>4</b>. Complexes <b>1</b> and <b>6</b> vapors demonstrated the lowest and the highest thermostability, respectively.</p