Carbyne decorated porphyrins

The Pd0/AuI-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.