Self-Assembled Mono- and Multilayers on Gold from 1,4-Diisocyanobenzene and Ruthenium Phthalocyanine

Self-assembled monolayers of 1,4-diisocyanobenzene on gold were used to bind ruthenium phthalocyanines to the surface by axial ligation of the macrocycle with isocyanide groups pointing out from the SAM. The 1,4-diisocyanobenzene SAM and the RuPc-1,4-diisocyanobenzene bilayer were characterized by ellipsometry, IRRAS, XPS, and SPM. The grafting of RuPc to the SAM is stable. The thickness of the film increases from 10 to 15 A upon RuPc ligation. IRRAS reveals that both ends of the 1,4-diisocyanobenzene are affected by the N⋮C to metal interaction occurring at the other end. XPS indicates that each RuPc macrocycle covers ∼12 1,4-diisocyanobenzene molecules in the bilayer.