Carbyne decorated porphyrins

Abstract

The Pd⁰/Au^I-mediated coupling between stannylcarbyne [W(CSnⁿBu₃)(CO)₂(Tp*)] (1) and meso-5,10,15,20-tetrakis(3′ or 4′-bromophenyl)porphyrins gives tetrametallic derivatives where a central porphyrin unit is formally substituted at the four meso positions by tungsten benzylidyne moieties. These new ‘metallo-porphyrins’ undergo metallation at the porphyrin centres with Zn(OAc)₂·2H₂O to give a pentametallic W₄Zn complex or at the tungsten–carbon triple bonds with [AuCl(SMe₂)] to give an octametallic W₄Au₄ complex. The Zn(II)-metalloporphyrin derivatives are capable of reversibly coordinating further axial ligands such as 4-dimethylaminopyridine or meta-pyridylcarbynes, which themselves are prepared via a coupling between 1 and the appropriate (di)bromopyridine.