The Effects of Noncovalent Interactions on Surface Structures Formed by Diketopyrrolopyrrole Pigment and Its Alkyl-Derivatives on HOPG Substrate
作者:Akinori Honda、Yoshinori Tamaki、Kazuo Miyamura
DOI:10.1246/bcsj.20150049
日期:2015.7.15
Two-dimensional self-assembled structures formed by diketopyrrolopyrrole Pigment Red 254 (3,6-bis(4-chlorophenyl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione) and its alkyl-derivatives at the liquid-HOPG interface were investigated by scanning tunneling microscope (STM). Pigment Red 254 is found to form two different surface structures (crystal-like structure and solvated crystal-like structure). Furthermore, in order to investigate the effect of hydrogen bonding, alkyl-derivatized Pigment Red 254 (PR-2Cn, n: alkyl chain length) were synthesized, and their self-assembled structures were analyzed. We found that surface structures of PR-2Cn varied depending on the intermolecular and molecule–substrate van der Waals interactions arising from the n-alkyl chains introduced instead of hydrogen bonding. Shorter alkyl chains of PR-2C10 resulted in the formation of multi domains. On the other hand, PR-2C12, PR-2C14, and PR-2C16 molecules that have longer alkyl chains formed stable single domain structures.
通过扫描隧道显微镜(STM)研究了二酮吡咯颜料红 254(3,6-双(4-氯苯基)-2,5-二氢吡咯并[3,4-c]吡咯-1,4-二酮)及其烷基衍生物在液体-HOPG 界面形成的二维自组装结构。结果发现,颜料红 254 形成了两种不同的表面结构(类晶体结构和溶解类晶体结构)。此外,为了研究氢键的影响,还合成了烷基衍生化颜料红 254(PR-2Cn,n:烷基链长度),并分析了它们的自组装结构。我们发现,PR-2Cn 的表面结构因引入的 n-烷基链代替氢键而产生的分子间和分子与基底之间的范德华相互作用而不同。PR-2C10 较短的烷基链会形成多结构域。另一方面,烷基链较长的 PR-2C12、PR-2C14 和 PR-2C16 分子则形成了稳定的单结构域。