title: Self-assembly and imprinting of macrocyclic molecules in layer-by-layered TiO2 ultrathin films.
abstract: Alternate TiO2 gel ultrathin films assembled with a macrocyclic carboxylic acids of tetrakis-4-carboxyphenyl porphine (TCPP) or tetra-4-carboxylphthalocyanine cobalt (II) (Co-TCPc) were prepared by the surface sol-gel process. To confirm the film growth and imprinting effect, quartz crystal microbalance (QCM) and UV-vis spectroscopy measurements were employed. The binding of TCPP was 1.2-14.3 times more selective compared to structurally related macrocyclic guest molecules. Among other findings, tetrakis-4-carboxymethyloxyphenyl porphine (TCMOPP) that has a spacer (-O-CH2-) between the phenyl rings and carboxylic acid moieties of TCPP showed a significantly lower binding efficiency equal to 0.07, regardless of its similar molecular structure to the template molecule. Structural difference of porphyrin and phthalocyanine analogs could be also selectively discriminated: the TCPP imprinted film showed ca. 13 times higher selectivity for recognition of TCPP itself from the mixture of TCPP and Co-TCPc. Characterization by AFM demonstrated that the TiO2/TCPP film has highly uniform surface and ultrathin thickness, while both TEM and SEM studies confirmed the immobilized structures of TCPP inside the film.
authors.affiliation: Graduate School of Environmental Engineering, The University of Kitakyushu, Wakamatsu-ku, Kitakyushu, Japan.
authors.forename: Kazuma
authors.initials: K
authors.lastname: Araki
authors.forename: Do-Hyeon
authors.initials: DH
authors.lastname: Yang
authors.forename: Tao
authors.initials: T
authors.lastname: Wang
authors.forename: Roman
authors.initials: R
authors.lastname: Selyanchyn
authors.forename: Seung-Woo
authors.initials: SW
authors.lastname: Lee
authors.forename: Toyoki
authors.initials: T
authors.lastname: Kunitake
mesh_terms: D047028:Macrocyclic Compounds / Q000737:chemistry*; D008567:Membranes, Artificial; D054802:Molecular Imprinting / Q000379:methods*; D015394:Molecular Structure; D014025:Titanium / Q000737:chemistry*
chemical_list: D047028:Macrocyclic Compounds; D008567:Membranes, Artificial; C009495:titanium dioxide; D014025:Titanium