Synthesis and structural characterization of phenylalanine-based Co(II) and Cd(II) 1D coordination polymers and their use as efficient catalysts for aerobic oxidation of cycloalkenes

FEDERICO MOVILLA; JUAN M. REY; LUIS SANTIBÁÑEZ; EVGENIA SPODINE; PATRICIO CANCINO; FLORENCIA DI SALVO

Congreso; ACS - SPRING MEETING; 2021

In recent years, the research of Coordination Polymers (CPs) is undergoing an enormous growth since they exhibit diverse structural architectures, known spatial configurations and high specificity regarding the adsorption and interaction with guest molecules. Among a wide variety of applications, catalysis is one of the most frequently explored. Amino acids are widely recognized as a versatile ligand class in organometallic and coordination chemistry catalysis. As an N,O-bidentate donor, amino acid-based ligands have considerable effects on the stereoelectronic nature of the resultant metal complex, providing the framework for the development of highly selective processes. Besides, due to the different coordination modes, amino acid-based ligands are also useful building blocks for the obtaining of biocompatible and chiral CPs. Herein, we present the synthesis and structural characterization of two new Co(II) (1) and Cd(II) (2) 1D CPs, derived from the biologically relevant aldehyde piperonal and the amino acid L-Phenylalanine (Figure). In addition, their use as catalyst for the heterogenous aerobic oxidation of cycloalkenes is also explored. Their structures were determined by single crystal X-ray diffraction experiments in the solid state and different spectroscopies in solution. Thermal studies show great responses, demonstrated their stability. The catalytic results show that both catalysts are active in the oxidation of cyclohexene achieving a conversion of 75% at 75°C, being cycloxenone the main product, indicating a 68% of selectivity. A remarkable result is that, the polymer based on Co(II) demonstrated to be also effective at room temperature (50% of conversion and 70% of selectivity).