Acid-catalysed additions of acetylenes to [XPd(µ-Ph2PCH2PPh2)2PdX](X = Cl, Br, or I) to give dimetallated olefin complexes of type [XPd(µ-Ph2PCH2PPh2)2(µ-HCCR)PdX](R = H, Ph, or C6H4Me-p)

Abstract

The addition of acetylenes to [XPd(µ-dppm)₂PdX](dppm = Ph₂PCH₂PPh₂; X = Cl, Br, or I) is catalysed by traces of acid and (in some cases) methanol, giving [XPd(µ-dppm)₂(µ-HCCR)PdX](R = H, Ph, or C₆H₄Me-p) containing the dipalladated olefin ligand HCCR. These reactions are readily reversed by heating or by photolysis. Hydrogen-1 and ³¹P-{¹H} n.m.r. and i.r. spectroscopic data are given and discussed.