Activation of SO 2 F 2 at a Rhodium PNP Pincer Complex: Ligand Supported S-F Bond Cleavage to Generate NSO 2 F 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.