Metal-mediated layer-by-layer assembly of zinc 5,10,15,20-tetrapyridylporphine and pyridyl derivatives

Metal-mediated assembly for the hybrid multilayers of multiporphyrin arrays of zinc 5,10,15,20-tetrapyridylporphyrin (ZnTPyP) with three kinds of pyridyl derivatives, poly(4-vinylpyridine) (PVP), 4,4′-bipyridyl (Bpy) and 2,4,6-tri(4-pyridyl)-1,3,5-triazine (TPyTa), have been constructed directly on solid surfaces. The assembly process was characterized with the use of X-ray photoelectron spectroscopy (XPS) and absorption spectroscopy. The Soret absorption intensity of ZnTPyP was proportional to the layer numbers, indicating a similar amount of ZnTPyP was assembled for each layer. The average surface density of ZnTPyP molecules per layer was estimated to be in the range of 3.5–4.0 × 10− 10 mol/cm2. Orientation angle for the porphyrin macrocycles relative to the substrate surface was about 50–60° for the multilayers of Pd–ZnTPyP, Pd–ZnTPyP–Bpy, Pd–ZnTPyP–TPyTa, and about 80° for the Pd–ZnTPyP–PVP, respectively. Atomic force microscopic images showed that the domain sizes and shapes of the hybrid multilayer arrays closely related to the inserted layers (PVP, BPy or TPyTa).