Addition and Metathesis Reactions of Zirconium and Hafnium Imido Complexes

Abstract

<p>The zirconium and hafnium imido metalloporphyrin complexes (TTP)MNAr<em>i</em>Pr (TTP = <em>meso</em>-5,10,15,20-tetra-<em>p</em>-tolylporphyrinato dianion; M = Zr (<strong>1</strong>), Hf; Ar<em>i</em>Pr = 2,6-diisopropylphenyl) were used to mediate addition reactions of carbonyl species and metathesis of nitroso compounds. The imido complexes react in a stepwise manner in the presence of 2 equiv of pinacolone to form the enediolate products (TTP)M[OC(<em>t</em>Bu)CHC(<em>t</em>Bu)(Me)O] (M = Zr (<strong>2</strong>), Hf (<strong>3</strong>)), with elimination of H2NAr<em>i</em>Pr. The bis(μ-oxo) complex [(TTP)ZrO]2 (<strong>4</strong>) is formed upon reaction of (TTP)ZrNAr<em>i</em>Pr with PhNO. Treatment of compound <strong>4</strong> with water or treatment of compound <strong>2</strong> with acetone produced the (μ-oxo)bis(μ-hydroxo)-bridged dimer [(TTP)Zr]2(μ-O)(μ-OH)2 (<strong>5</strong>). Compounds <strong>2</strong>, <strong>4</strong>, and <strong>5</strong> were structurally characterized by single-crystal X-ray diffraction.</p>