A new type of oxidative addition of an iodoarene to a Pd(ii) complex

Abstract

Oxidative addition of N-(2-iodophenyl)formamide to Pd(dba)₂ (dba = dibenzylideneacetone) in the presence of 4,4′-ditertbutyl-2,2′-bipyridine (^tBubpy) produces [Pd(C₆H₄NHCHO-2)I(^tBubpy)] (1) which inserts 2-iodophenyl isocyanide to give [Pd{C(NC₆H₄I-2)C₆H₄NHCHO-2}I(^tBubpy)] (2). Dehydroiodination of 2 with Tl(acac) (acacH = acetylacetone) gives the stable Pd(IV) complex OC-6-35-[Pd{C,N,N–C(NC₆H₄-2)C₆H₄NCHO-2}I(^tBubpy)] (4) likely resulting from the spontaneous oxidative addition of the I–Ar moiety present in the unstable intermediate Pd(II) complex [Pd{C,N–C(NC₆H₄I-2)C₆H₄NCHO-2}(^tBubpy)] (3). The crystal structure of 4 shows various C–H⋯O hydrogen bonds resulting in chains of dimers stacked along the a axis.