Kinetic studies of the reactions of the carbene complex W(CO)5[C(SCH3)2] with phosphines to form phosphorane complexes W(CO)5[(CH3S)2C-PR3] and the synthesis of some cyclic phosphorane complexes

摘要: Abstract The dithiocarbene complex W(CO)5[C(SCH3)2 reacts with tertiary phosphines, PPh2CH3, PPh(CH3)2, P(C2H5)3 and P(OCH3)3 to form the phosphorane complexes W(CO)5[CH3S)2C-PR3] HPPh2 phosphine W(CO)5[PPh2[CH(SCH3)2]. Kinetic studies of both types reactions show that their rates are first order each in W(CO)5[C(SCH3)2] phosphorus ligand. A mechanism involving rate determining attack at carbene carbon followed by rapid rearrangement product is consistent this law. Rate constants for increase increasing nucleophilicities phosphines: PPh2H > PPh2(CH3) PPh(CH3)2 P(C2H5)3) as phosphines increase. ΔS values (≈-30 e.u.) remain essentially constant all reactions. cyclic dithiorcarbenes W(CO)5[CS(CH2)nS], wheren- 3 or 4, react complexes, W(CO)5[S(CH2)nSC-PPh2(CH3)]. 6- 7- membered dithiocarbenes also W(CO)5 {PPh2- [CS(CH2)nS(H)]}.