Surface-reaction Induced Supramolecular Structure

The copper induced 5,15-diphenylporphyrin metalation on Au(111) surface is studied by ultra high vacuum scanning tunneling microscopy(STM) operated at room temperature. By controlling the depositing sequences of the guest copper atoms and5,15-diphenylporphyrin molecules on Au(111) surface, we investigated the how the copper atoms enter the macrocycles of the 5,15-diphenylporphyrin molecules at atomic level and found that the copper atoms prefer to form islands underneath the5,15-diphenylporphyrin molecular layer regardless of whether they are deposited before the deposition of 5,15-diphenylporphyrin molecules or after the deposition of5,15-diphenylporphyrin molecules at room temperature. As a consequence, when such copper atoms acquire enough energy, they will enter the macrocycles of the5,15-diphenylporphyrin molecules from the bottom of the molecules and metalate with the molecules.The self-assembled structure of 5,15-diphenylporphyrin molecules on Ag(110)surface are investigated by STM operated at room temperature and the design and investigation of fabricating the conjugate molecular chains with 5,15-diphenylporphy rin molecules by dehydrogenative homocoupling are studied by room temperature STM and liquid Nitrogen temperature STM. The growth directions of both self-assembled structures of 5,15-diphenylporphyrin molecules and the dehydrogenate d molecular chains are meditated by the lattice structure of Ag(110)surface. The low temperature STM investigations ambiguously demonstrated that the silver adatoms may participate in catalyzing the dehydrogenative homocoupling between 5,15-diphenylporphyrin molecules and the decreased electronic gap of the reacted 5,15-diphenylporphyrin molecular chains.Surface-assisted cyclotrimerization induced conformational changes of4-ethynyltriphenylamine(ETPA) molecular self-assembly on Au(111) surface are unraveled by scanning tunneling microscopy at room temperature in ultrahigh vacuum conditions. The observations illustrate that the cyclotrimerization of the ETPA molecules occurs at 50℃ and the ETPA molecules only react to one type of achiral trimers caused by the steric hindrance between the ETPA molecules. Suchproducts finally form chiral hexagonal packed supramolecular structures which are able to self-heal on the Au(111) surface.