Theoretical study of the structure, vibrational spectra, and electronic spectra of oxotitanium porphyrin, octamethylporphyrin, porphyrazine, and phthalocyanine complexes

Amplified Electrochemical Hydrogen Peroxide Sensing Based on Cu-Porphyrin Metal-Organic Framework Nanofilm and G-Quadruplex-Hemin DNAzyme

A novel electrochemical hydrogen peroxide (H₂O₂) sensor based on Cu-porphyrin(Cu-TCPP)/G-quadruplex-hemin nanocomposite was constructed by assembling two-dimensional Cu-TCPP metal-organic framework (MOF) nanofilm and G-quadruplex-hemin DNAzyme. The Cu-TCPP synthesized by the surfactant-assisted method has a wrinkled two-dimensional nanofilm morphology, which gives it a large surface area and accessible active sites. Cu-TCPP exhibits peroxidase activity and good stability and can catalyze the reduction of H₂O₂. In addition, Cu-TCPP can be used as a nanocarrier for G-quadruplex-hemin DNAzyme with strong peroxidase activity to achieve "biological barcode" amplification and improve stability. The cooperative interaction of Cu-TCPP and G-quadruplex-hemin DNAzyme effectively amplifies the electrochemical response signal. Electrochemical studies have shown that the constructed sensor exhibits good electrochemical sensing performance with three linear ranges: 0.08 μM to 0.11 mM, 0.11-0.91 mM, and 0.91-8.1 mM, with sensitivities of 2315.86, 301.00, and 65.71 μA/(mM cm²), respectively, and the detection limit was 0.03 μM. In addition, the sensor shows good selectivity. In summary, this study provides a simple and effective new strategy for electrochemical sensing based on two-dimensional MOFs and artificial enzymes.

Thermal stability and interlayer exchange processes in heterolayers of TiOPc and PTCDA on Ag(1 1 1)

Organic-organic interfaces, in particular donor-acceptor type heterointerfaces, represent central elements of organic electronic devices. Understanding and controlling their physical properties is key to improve and modify their performance. For this purpose we have investigated the structural properties and thermal evolution of molecular heterointerface model systems. Specifically, various stacked titanyl-phthalocyanine (TiOPc)-3,4,9,10-perylene-tetracarboxylic-dianhydride (PTCDA) heterolayers grown on Ag(1 1 1) have been examined using Fourier transform infrared absorption spectroscopy and spot-profile analysis low-energy electron diffraction. An accurate description of the thermal evolution and prevalence of the various phases of TiOPc and PTCDA is derived from the spectral signatures of the two molecular species explored in previous studies. Exceptionally high thermal stability is found for stacked heterolayers comprising TiOPc double layers with characteristic up-down arrangement of its axial Ti-O unit and single layers of PTCDA. Thereby, interlayer exchange is negligible in a wide temperature range ([Formula: see text] K). This is ascribed to attractive intermolecular interaction (dipole-dipole interaction, hydrogen bonding) among the TiOPc molecules oriented face-to-face within the TiOPc bilayer sheet. Stacked layers of comprising single layers of TiOPc and of PTCDA turn out to be thermally much less stable and more heterogeneous. In the course of their thermal evolution, a number of processes such as interlayer exchange, TiOPc double-layer formation and dewetting are encountered.

Oxotitanium-porphyrin for selective catalytic reduction of NO by NH3: a theoretical mechanism study

Nitric oxide reduction catalyzed by oxotitanium-porphyrin.

The discrete nature of inhomogeneity: the initial stages and local configurations of TiOPc during bilayer growth on Ag(111)

Microscopic model for the growth of TiOPc bilayers on Ag(111) and identification of local configurations thereof.