Synthesis and Characterization of V<sup>V</sup>(3,6-DBSQ)(3,6-DBCat)<sub>2</sub>, a d<sup>0</sup> Metal Complex with Dioxygenase Catalytic Activity Aimee M. Morris Cortlandt G. Pierpont Richard G. Finke 10.1021/ic802122q.s001 https://acs.figshare.com/articles/journal_contribution/Synthesis_and_Characterization_of_V_sup_V_sup_3_6_DBSQ_3_6_DBCat_sub_2_sub_a_d_sup_0_sup_Metal_Complex_with_Dioxygenase_Catalytic_Activity/2862706 Transition-metal complexes containing redox-active quinoid ligands are of interest because of their catalytic capabilities in multielectron, substrate-activation reactions such as dioxygenase catalysis using O<sub>2</sub>. The new catecholate complex V<sup>V</sup>(3,6-DBSQ)(3,6-DBCat)<sub>2</sub> (where 3,6-DBSQ = 3,6-di-<i>tert</i>-butylsemiquinone and 3,6-DBCat = 3,6-di-<i>tert</i>-butylcatecholate) was synthesized by combining VO(acac)<sub>2</sub> with 1 equiv of 3,6-DBBQ (where 3,6-DBBQ = 3,6-di-<i>tert</i>-butylbenzoquinone) and 2 equiv of H<sub>2</sub>(3,6-DBCat) in dry methanol under an inert atmosphere. The resultant complex was characterized by single-crystal X-ray diffraction, elemental analysis, near-IR, UV/vis, and electron paramagnetic resonance (EPR) spectroscopy. The crystallography as well as the near-IR and EPR studies suggest that the radical spin is localized on the 3,6-DBSQ ligand at room temperature, making V<sup>V</sup>(3,6-DBSQ)(3,6-DBCat)<sub>2</sub> a type 1 mixed-valence complex. Initial dioxygenase catalysis studies reveal that V<sup>V</sup>(3,6-DBSQ)(3,6-DBCat)<sub>2</sub> is a good dioxygenase precatalyst for the substrate H<sub>2</sub>(3,6-DBCat) with O<sub>2</sub> in ca. 600 total turnovers to >93% intra- and extradiol products with only 1−2% of the undesired benzoquinone autoxidation product. 2009-04-20 00:00:00 EPR studies ligand 0 Metal Complex UV extradiol products O 2. 2 equiv dioxygenase catalysis O 2 DBBQ Initial dioxygenase catalysis studies undesired benzoquinone autoxidation product dioxygenase precatalyst VO VV 1 equiv room temperature DBSQ