Self-assembly and layer-by-layer deposition of metallosupramolecular perylene bisimide polymers

2,2′:6′,2″-Terpyridine (tpy)-functionalized red and green perylene bisimide (PBI) building blocks were synthesized, and their metal-ion-directed self-assembly was studied in detail by 1H NMR, DOSY NMR, and UV-vis spectroscopy. These studies revealed that the newly synthesized ditopic bis(tpy)-PBI ligands, in which the tpy units are directly connected to PBI moieties at the imide positions, form supramolecular coordination polymers upon addition of one equivalent of Zn(II) ions. Atomic force microscopy (AFM) investigations confirmed the formation of extended, rigid polymers with average chain lengths of up to 30–35 repeat units. These coordination polymers create closely packed films with linear arrangement on mica and HOPG surfaces. The Zn(II) centers were mapped by applying current imaging tunnelling spectroscopy (CITS) to the red-coloured polymer deposited on graphite surfaces. An enhanced local density of unoccupied states close to the Fermi energy was observed in positions with metal ions. Alternate multilayer films of two different coordination polymers were prepared by the layer-by-layer deposition technique and surface densities Γ of perylene bisimide chromophores in these films were determined.

合成了2,2′:6′,2″ - 三联吡啶（tpy）功能化的红色和绿色苝酰亚胺（PBI）结构单元，并通过1H NMR、扩散排序谱（DOSY NMR）和紫外 - 可见光谱对它们的金属离子导向自组装进行了详细研究。这些研究表明，新合成的双位点双（tpy）- PBI配体（其中tpy单元在酰亚胺位置直接连接到PBI部分）在加入一当量的Zn(II)离子时形成超分子配位聚合物。原子力显微镜（AFM）研究证实形成了平均链长可达30 - 35个重复单元的伸展的刚性聚合物。这些配位聚合物在云母和高定向热解石墨（HOPG）表面形成紧密堆积的线性排列薄膜。通过对沉积在石墨表面的红色聚合物应用电流成像隧道谱（CITS）对Zn(II)中心进行了定位。在有金属离子的位置观察到接近费米能级的未占据态的局部密度增强。通过逐层沉积技术制备了两种不同配位聚合物的交替多层膜，并测定了这些膜中苝酰亚胺生色团的表面密度Γ。