[cheesewithwhine]

For late metals such as Ir, Pt, Pd, is tert-butyl or trimethylsilyl a better ligand? I think it's tert-butyl because carbon is a better sigma donor than silicon, but I suspect it's more complicated than that. Thanks. 

[spirochete]

A mod should move this to inorganic chemistry. You'd get a better response there. I would assume silicon could also accept back bonding from the metal into various orbitals but I'm not an expert on inorganic chemistry.