Activation of SO₂F₂ at a Rhodium PNP Pincer Complex: Ligand Supported S−F Bond Cleavage to Generate NSO₂F Derivatives

The κ 2 ‐(P,N)−phosphine ligand precursor NH(CH 2 CH 2 PCy 2 ) 2 can be used for the synthesis of the rhodium(I) complex [Rh(CO){ ĸ 3 ‐(P,N,P)−Cy 2 PC 2 H 4 NHC 2 H 4 PCy 2 }][Cl] ( 1 ). The deprotonated complex [Rh(CO){ ĸ 3 ‐(P,N,P)−Cy 2 PC 2 H 4 NC 2 H 4 PCy 2 }] ( 2 ) shows a cooperative reactivity of the PNP ligand in the activation reaction of SO 2 F 2 to yield the rhodium fluorido complex trans ‐[Rh(F)(CO){ ĸ 2 ‐(P,P)−Cy 2 PC 2 H 4 N(SO 2 F)C 2 H 4 PCy 2 }] 2 ( 3 ) by S−F bond cleavage. It is remarkable that no reaction was observed when 3 was treated with hydrogen sources e. g. dihydrogen, organosilicon compounds such as triethylsilane or TMS−CF 3 and different fluorine sources such as SF 4 or Selectfluor®. However, the treatment of complex 3 with XeF 2 in the presence of CsF resulted in the formation of the unique fluorido rhodium(III) complex cis , trans ‐[Rh(F) 3 (CO){ ĸ 2 ‐(P,P)−Cy 2 PC 2 H 4 N(SO 2 F)C 2 H 4 PCy 2 }] 2 ( 4 ). In the presence of pyridine(HF) X or BF 3 the fluorido complex 3 converted into the dicationic complexes [Rh(CO){ ĸ 2 ‐(P,P)−Cy 2 PC 2 H 4 N(SO 2 F)C 2 H 4 PCy 2 }] 2 [XF] 2 , X=HF ( 5 ) or BF 3 ( 6 ), respectively.