Synthesis and Supramolecular Self-Assembly Study of a Novel Porphyrin Molecule in Langmuir and Langmuir-Blodgett Films

The self-assembly and supramolecular engineering of porphyrins into ordered arrays have recently attracted much interest because of their promising application potential in molecular and electronic devices, spintronics, energy harvestingandstorage, catalysis,andsensor development.Weherein report the synthesis and supramolecular self-assembly study of a novel porphyrin molecule, 2Por-TAZ, in Langmuir and Langmuir-Blodgett films. The 2Por-TAZ molecule contains two porphyrin macrocycles attached to a triaminotriazine headgroup. Triaminotriazines are known to form a highly ordered linear supramolecular self-assembly through complementary hydrogen bonding with barbituric acid molecules at the air-water interface. Surface pressure-area isotherm measurements and polarized UV-vis absorption spectroscopic studies indicate that the 2Por-TAZ molecules adopted an edge-on orientation at the air-water interface. Polarized UV-vis absorption study also revealed that the 2Por-TAZ molecules formed linear supramolecular networks on pure water and barbituric acid subphase with porphyrin flat planes facing toward the compression direction. The binding of barbituric acid with 2Por-TAZ molecules was observed from the expansion of the Langmuir monolayer film. Compared to the transferredLBfilm from pure water subphase, both theUV-vis absorbance and fluorescence emission intensity of theLBfilm transferred from barbituric acid subphase increased significantly.