Sensory Parameters and Chemical Affinity to N-Bases of Molybdenum(V) Porphyrin Complexes Depending on the Structure of Ligands

Abstract

In order to improve the sensor properties of molybdenum(V) porphyrin complexes, namely, their sensitivity to volatile organic bases, and taking into account the influence of the macrocyclic ligand periphery composition on the electron distribution in the π-system and on the interactions along the axial axis, (ethoxy)oxo[5,10,15,20-tetra(4-trifluoromethylphenyl)porphinato]molybdenum(V) was synthesized, its molecular structure and its spectral and optical sensory parameters were determined, and the thermodynamics of the reaction with pyridine was studied. The chemical structure of the compound and its donor–acceptor complexes with pyridine was established using electron absorption and infrared spectroscopy, nuclear magnetic resonance spectroscopy and mass spectrometry. Using the literature data on the topic of study, the relationship between the sensor properties of molybdenum(V) porphyrin complexes and the structure of their molecules was revealed. The obtained sensor characteristics—relative optical response, minimum detection limit for base concentration, and instantaneous circulation and response times—confirm the high potential of the synthesized complex for the creation of optical sensor devices for the detection of volatile organic compounds. The pyridine fragment was used as a bridge to obtain donor–acceptor dyads of the complex with N-methyl-2-(pyridin-4-yl)-3,4-fullero[60]pyrrolidine, which are expected to exhibit photoinduced electron transfer in a toluene medium.