10.1021/ja054941t.s003 María Alonso María Alonso M. Angeles Alvarez M. Angeles Alvarez M. Esther García M. Esther García Miguel A. Ruiz Miguel A. Ruiz Hayrullo Hamidov Hayrullo Hamidov John C. Jeffery John C. Jeffery Oxidation Reactions of the Phosphinidene Oxide Ligand American Chemical Society 2005 Mo 2 Cp 2 thiooxophosphorane complexes S 8 Bu Phosphinidene Oxide Ligand BF 4 multisite activity phosphinous acid OH Oxidation Reactions DBU P atoms OP SP oxidizing agents thiooxophosphorane anion 2 CO 2 EP novel organophosphorus ligands bond phosphinidene oxide MoCp O positions novel dioxophosphorane sulfur atoms FeCp 2 P site 2005-11-02 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Oxidation_Reactions_of_the_Phosphinidene_Oxide_Ligand/3259564 The (H-DBU)<sup>+</sup> salt of the anionic phosphinidene oxide complex [MoCp(CO)<sub>2</sub>{P(O)R*}]<sup>-</sup> (<b>1</b>) (DBU = 1,8-diazabicyclo[5.4.0]undec-7-ene; R* = 2,4,6-C<sub>6</sub>H<sub>2</sub><i><sup>t</sup></i><sup></sup>Bu<sub>3</sub>) reacts with different oxidizing agents, displaying a multisite activity located at the Mo and P atoms or at the MoP bond. Thus, reaction of <b>1</b> with [FeCp<sub>2</sub>]BF<sub>4</sub> gives the dimer [Mo<sub>2</sub>Cp<sub>2</sub>(CO)<sub>4</sub>{P(O)R*}<sub>2</sub>], and reaction with bromine gives the phosphinous acid complex [MoBrCp{P(OH)(CH<sub>2</sub>CMe<sub>2</sub>C<sub>6</sub>H<sub>2</sub><i><sup>t</sup></i><sup></sup>Bu<sub>2</sub>}(CO)<sub>2</sub>], the latter arising from an unprecedented C−H bond addition to the oxide PO moiety. In contrast, reaction of <b>1</b> with <i>p</i>-benzoquinone occurs at the P site to give the <i>P</i>,<i>O</i>-bound phosphonite complex [MoCp{κ<sup>2</sup>-OP(OC<sub>6</sub>H<sub>4</sub>OH)R*}(CO)<sub>2</sub>]. Finally, oxygen or sulfur atoms are added to the MoP bond by reaction of <b>1</b> with Me<sub>2</sub>CO<sub>2</sub> and S<sub>8</sub> to give the novel dioxophosphorane or thiooxophosphorane complexes [MoCp(CO)<sub>2</sub>{κ<sup>2</sup>-EP(O)R*}]<sup>-</sup> (E = O, S). The thiooxophosphorane anion is a good nucleophile and is methylated at either the S or O positions depending on the electrophile used (MeI or (Me<sub>3</sub>O)BF<sub>4</sub>) to give the isomers [MoCp{κ<sup>2</sup>-(MeS)P(O)R*}(CO)<sub>2</sub>] and [MoCp{κ<sup>2</sup>-SP(OMe)R*}(CO)<sub>2</sub>], both having novel organophosphorus ligands.