Reactions of [Re(NO)2(PR3)2][BAr F4] complexes with phenylacetylene

Article abstract of DOI:10.1023/B:RUCB.0000041309.19570.1d

The reaction of [Re(NO)₂(PR₃)₂][BAr ^F₄] (R = cyclo-C₆H₁₃ (1a), Pr ⁱ (1b); [BAr^F₄]^- = [B(3,5-(CF ₃)₂C₆H₃)₄]) with phenylacetylene in the presence of a non-nucleophilic base, like 2,6-bis(tert-butyl)pyridine (BTBP) or Bu^tOK, affords the phenylethynyl complexes [Re(C≡CPh)(NO)₂(PR₃) ₂] (R = cyclo-C₆H₁₃ (2a); Prⁱ (2b)) in moderate yields. In the absence of a base, complexes 1a and 1b are transformed into the compounds [Re(C≡CPh)(CH=C(Ph)ONH)(NO)(PR ₃)₂][BAr^F₄] (3a and 3b, respectively). The structure of complex 3a was confirmed by X-ray diffraction analysis. The latter reaction is proposed to be initiated by deprotonation of the terminal alkyne H atom by the bent nitrosyl ligand followed by the subsequent 1,3-dipolar addition of the ReN(H)O moiety to phenylacetylene.