Oxidation Reactions of the Phosphinidene Oxide Ligand

The (H-DBU)+ salt of the anionic phosphinidene oxide complex [MoCp(CO)2{P(O)R*}]- (1) (DBU = 1,8-diazabicyclo[5.4.0]undec-7-ene; R* = 2,4,6-C6H2tBu3) 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 1 with [FeCp2]BF4 gives the dimer [Mo2Cp2(CO)4{P(O)R*}2], and reaction with bromine gives the phosphinous acid complex [MoBrCp{P(OH)(CH2CMe2C6H2tBu2}(CO)2], the latter arising from an unprecedented C−H bond addition to the oxide PO moiety. In contrast, reaction of 1 with p-benzoquinone occurs at the P site to give the P,O-bound phosphonite complex [MoCp{κ2-OP(OC6H4OH)R*}(CO)2]. Finally, oxygen or sulfur atoms are added to the MoP bond by reaction of 1 with Me2CO2 and S8 to give the novel dioxophosphorane or thiooxophosphorane complexes [MoCp(CO)2{κ2-EP(O)R*}]- (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 (Me3O)BF4) to give the isomers [MoCp{κ2-(MeS)P(O)R*}(CO)2] and [MoCp{κ2-SP(OMe)R*}(CO)2], both having novel organophosphorus ligands.

（H-DBU）+ 盐的阴离子磷氮氧化物复合物 [MoCp(CO)2{P(O)R*}]-(1)（DBU=1,8-二氮杂双环[5.4.0]十一碳-7-烯；R*=2,4,6-C6H2tBu3）与不同的氧化剂反应，表现出位于 Mo 和 P 原子或 Mo-P 键的多位点活性。因此，1 与 [FeCp2]BF4 反应生成二聚体 [Mo2Cp2(CO)4{P(O)R*}2]，与溴反应生成磷酸复合物 [MoBrCp{P(OH)(CH2CMe2C6H2tBu2}(CO)2]，后者源于对氧化物 P-O 结构单元前所未有的 C-H 键加成。相反，1 与对苯醌的反应发生在 P 位点，生成 P-O 键合的磷酸盐复合物 [MoCp{κ2-OP(OC6H4OH)R*}(CO)2]。最后，通过 1 与 Me2CO2 和 S8 的反应，在 Mo-P 键上添加氧或硫原子，生成新的二氧磷杂烷或硫氧磷杂烷复合物 [MoCp(CO)2{κ2-EP(O)R*}]-(E=O, S)。硫氧磷杂烷阴离子是一种良好的亲核试剂，并且根据使用的亲电试剂（MeI 或 (Me3O)BF4）在 S 或 O 位置进行甲基化，生成异构体 [MoCp{κ2-(MeS)P(O)R*}(CO)2] 和 [MoCp{κ2-SP(OMe)R*}(CO)2]，两者均具有新颖的有机磷配体。