The mechanism of the C-H bond activation of hydrocarbons by a nonheme chromium(IV) oxo complex bearing an N-methylated tetraazamacrocyclic cyclam (TMC) ligand, [Cr(IV)(O)(TMC)(Cl)](+) (2), has been investigated experimentally and theoretically. In experimental studies, reaction rates of 2 with substrates having weak C-H bonds were found to depend on the concentration and bond dissociation energies of the substrates. A large kinetic isotope effect value of 60 was determined in the oxidation of dihydroanthracene (DHA) and deuterated DHA by 2. These results led us to propose that the C-H bond activation reaction occurs via a H-atom abstraction mechanism, in which H-atom abstraction of substrates by 2 is the rate-determining step. In addition, formation of a chromium(III) hydroxo complex, [Cr(III)(OH)(TMC)(Cl)](+) (3), was observed as a decomposed product of 2 in the C-H bond activation reaction. The Cr(III)OH product was characterized unambiguously with various spectroscopic methods and X-ray crystallography. Density functional theory (DFT) calculations support the experimental observations that the C-H bond activation by 2 does not occur via the conventional H-atom-abstraction/oxygen-rebound mechanism and that 3 is the product formed in this C-H bond activation reaction. DFT calculations also propose that 2 may have some Cr(III)O(•-) character. The oxidizing power of 2 was then compared with that of a chromium(III) superoxo complex bearing the identical TMC ligand, [Cr(III)(O2)(TMC)(Cl)](+) (1), in the C-H bond activation reaction. By performing reactions of 1 and 2 with substrates under identical conditions, we were able to demonstrate that the reactivity of 2 is slightly greater than that of 1. DFT calculations again support this experimental observation, showing that the rate-limiting barrier for the reaction with 2 is slightly lower than that of 1.

Mononuclear Mn(III) -peroxo and dinuclear bis(μ-oxo)Mn(III) 2 complexes that bear a common macrocyclic ligand were synthesized by controlling the concentration of the starting Mn(II) complex in the reaction of H2 O2 (i.e., a Mn(III) -peroxo complex at a low concentration (≤1 mM) and a bis(μ-oxo)Mn(III) 2 complex at a high concentration (≥30 mM)). These intermediates were successfully characterized by various physicochemical methods such as UV-visible spectroscopy, ESI-MS, resonance Raman, and X-ray analysis. The structural and spectroscopic characterization combined with density functional theory (DFT) calculations demonstrated unambiguously that the peroxo ligand is bound in a side-on fashion in the Mn(III) -peroxo complex and the Mn2 O2 diamond core is in the bis(μ-oxo)Mn(III) 2 complex. The reactivity of these intermediates was investigated in electrophilic and nucleophilic reactions, in which only the Mn(III) -peroxo complex showed a nucleophilic reactivity in the deformylation of aldehydes.

The purpose of this study was to evaluate printing of various food internal structures using the beeswax (BW) oleogels with varying concentrations and explore the possibility of the fat replacement. Therefore, this work descibed the rheological properties of BW oleogels and the lard, as well as the printing precision and texture characteristics of printed products. Rheological measurements such as flow curves, temperature tests, strain tests and frequency tests were performed to evaluate the proper printability of BW oleogels and the lard. Then, the print dimensional deviation was analyzed to evaluate the geometrical accuracy of the printed products and a compression test was performed to assess the texture properties. As a result of rheological studies, the values of the storage modulus (G'), loss modulus (G'') and complex modulus (G*) of the gel increased as the concentration of the BW increased, and the lard was similar to the BW‐15. Then, Most of the printed products have been successfully printed and can be used as the printable materials when the BW concentration is at least 11%. As a result of dimensional deviation measurement, the products printed with the infill level of less than 75% and the BW concentrations of more than 15% showed the lowest dimensional deviation for the designed models and the best printing precision. The texture measurement showed that the BW concentrations and infill level significantly affected the hardness, cohesiveness and adhesiveness of the printed product. Finally, for the optimization of multiple responses, the texture characteristics (hardness, cohesiveness and adhesiveness) of the lard printed at 75% infill level were applied to a fixed target value, and the preparation parameters were selected as 59% infill level and 16% BW concentrations. Printed BW oleogels with predictive preparation parameters achieved similar hardness, cohesiveness and adhesiveness as the lard. In conclusion, it has been proven that 3D printing based on the BW oleogel system can produce complex internal structures to adjust the texture properties of the printed samples, and BW oleogels ware suggested that it has excellent potential as a replacement of the fat.

In this study, we investigated the optimal conditions for 3D structure printing of alternative fats that have the textural properties of lard using beeswax (BW)-based oleogel by a statistical analysis. Products printed with over 15% BW oleogel at 50% and 75% infill level (IL) showed high printing accuracy with the lowest dimensional printing deviation for the designed model. The hardness, cohesion, and adhesion of printed samples were influenced by BW concentration and infill level. For multi-response optimization, fixed target values (hardness, adhesiveness, and cohesiveness) were applied with lard printed at 75% IL. The preparation parameters obtained as a result of multiple reaction prediction were 58.9% IL and 16.0% BW, and printing with this oleogel achieved fixed target values similar to those of lard. In conclusion, our study shows that 3D printing based on the BW oleogel system produces complex internal structures that allow adjustment of the textural properties of the printed samples, and BW oleogels could potentially serve as an excellent replacement for fat.