Formation of multinuclear metal-terpyridyl complexes covalently bound to carbon substrates

Multinuclear complexes consisting of metal ions and a bis(terpyridyl) ligand were covalently bound to carbon substrates. The bonding of the complexes is initiated by the bonding of phenylterpyridine (PT) on the substrates using its in-situ-generated diazonium derivative, followed by stepwise coordination of the metal ions and the ligand on it. The bonding of the PT and the formation of the multinuclear complexes were confirmed by XPS, AFM, and CV measurements. The heterogeneous rate constant (k) at the Co complex-substrate interface was evaluated by chronoamperometry (CA). The estimated high k=(2.9-3.6) × 10³ s^-1) would be attributed to the C-C bond at the interface without interrupting the conjugation. These multinuclear complexes bound to the carbon substrates can facilitate electron transfer from redox species such as enzymes.