Protonation and Sulfidation of [(Me ₃ tacn)MO ₃ ] (M=Mo, W)

Abstract Protonation of [(Me 3 tacn)MoO 3 ] with one or two equivalents of strong proton acid afforded mono‐protonated complex [(Me 3 tacn)Mo VI O 2 (OH)](CF 3 SO 3 ) and bi‐protonated complex [(Me 3 tacn)Mo VI O(OH) 2 ](PF 6 ) 2 , respectively. Sulfidation with i Pr 2 NCS 2 Na or CS 2 in acetonitrile, followed by in situ protonation of [(Me 3 tacn)MO 3 ] (M=Mo, W), produced two monomeric complexes [(Me 3 tacn)Mo VI O 2 S] ⋅ ( i Pr 2 NH 2 ) ⋅ (PF 6 ) ⋅ CH 2 Cl 2 and [(Me 3 tacn)W VI O 2 S], and two dimeric complexes [(Me 3 tacn)Mo V O( μ ‐S) 2 Mo V O( κ 2 ‐S 2 C=O)] ⋅ CH 3 CN and [(Me 3 tacn)Mo IV O] 2 ( μ ‐O)( μ ‐S 2 ) ⋅ 2DMF. The crystal structures of the two protonated molybdenum(VI) complexes and the four oxo‐sulfido molybdenum/tungsten complexes have been determined. Moreover, the complexes have been characterized by infrared, Raman, fluorescence and UV‐vis spectroscopies. (Me 3 tacn=1,4,7‐trimethyl‐1,4,7‐triazacyclonane).