Syntheses and Characterization of Molybdenum Complexes with the (1,3‐Dithioliumyl)diphenylphosphine Containing Ligands

Treatment of [Et 4 N][Mo(CO) 5 (PPh 2 CS 2 )], 1 with unsaturated organic halides afforded the neutral complexes Mo(CO) 5 (PPh 2 CS 2 R) (R = CH 2 CN, 2 ; R = CH 2 C≡CH, 3 ). Alkylation reactions take place at the sulfur atom. Protonation of complex 2 and 3 with HBF 4 produced the intramolecular cyclization products [Mo(CO) 5 (PPh 2 CS 2 C 2 H 3 N)][BF 4 ], 4 and [Mo(CO) 5 (PPh 2 CS 2 C 3 H 4 )][BF 4 ], 5 , respectively. In complex 4 and 5 , two five‐membered 1,3‐dithiolium rings formed. Protonation of 3 to 5 is not reversible, but deprotonation of 4 by n ‐BuLi or PPh 3 gave 2 quantitatively. Treatment of 4 with n ‐Bu 4 NF yielded complex Mo(CO) 5 PPh 2 F, 6 and 2 with 1:1 ratio, but in the reaction of 5 and n ‐Bu 4 NF only compound 6 was formed. All of these complexes are identified by spectroscopic methods.