A direct observation on the surface assembling and ordering of coumarin derivatives on the graphite surface

Mechanistic Origins of Hierarchical Order in Organic Monolayers Deposited From Liquid Crystal Solvents

“…At the molecular scale, BOC films deposited from all three solvents were indistinguishable, with molecules crystallizing into parallel rows composed of unit cells containing four molecules (Figure a, unit cell dimensions a = 1.8 ± 0.2 nm, b = 5.1 ± 0.2 nm, α = 70 ± 2°). This differed from the arrangement of BOC molecules on graphite deposited from toluene reported by Pan et al, where the angle between the lamellar rows and the alkyl tails was either 81 ± 2° or 36 ± 2° depending on film preparation conditions, versus 61 ± 4° found in this work, and the area per molecule was significantly smaller than in films deposited from toluene. In addition to the polymorph shown in Figure a, a second, much less common molecular arrangement was also sometimes observed (not shown).…”

Alkyl Chain Length Dependence of the Self-Organized Structure of Alkyl-Substituted Phthalocyanines

“…Even when the quasi-3-fold symmetrical structure shown in Figure b,d was formed, the decrement of the area of the unit cells was not so large. STM results regarding unsubstituted and substituted alkane molecules adsorbed on graphite surfaces have shown that they form a well-ordered array with a characteristic lamellar structure of 2-fold symmetry. − These results led us to conclude that to reduce the size of the cavities and to gain the intermolecular interaction energy of the alkane molecules as much as possible the molecules tend to form densely packed structures by reducing the symmetry.…”

“…Octaalkoxyl-substituted phthalocyanines (C n OPc; n is the number of carbon atoms) have 4-fold symmetrical structures as shown Figure . According to previous results, octyloxy-substituted phthalocyanine (C 8 OPc) formed 3-fold and 4-fold symmetrical structures on graphite surfaces 25a. Therefore, we considered that the C n OPc molecules would have the possibility to form various two-dimensional ordered structures on graphite surfaces by changing the length of the substituted alkyl chain.…”

“…The other approach to form well-ordered stable monolayers of functionalized molecules is the utilization of alkyl chain-assisted SAMs represented by alkyl chain-substituted compounds on a graphite surface. − Unsubstituted and substituted alkanes have been used as a model system to study the interactions that control molecular adsorption and self-assembly on graphite. − It is well-known that the alkyl-substituted porphyrins and phthalocyanines rearranges in lines or discrete states with regular spacing on highly oriented pyrolytic graphite (HOPG) surfaces under ambient conditions. 25a,25b, Metalloporphyrins and metallophthalocyanines have the ability to immobilize the desired organic molecules through axial coordination to the central metal atom. We succeeded in synthesizing porphyrin-stoppered rotaxane through the coordinate linkage of rhodium(III) (Rh(III)) porphyrin derivative .…”