RESUMO
Titanium phosphorus oxides (TiPOs) are promising energy-conversion materials, but most are of tetravalent titanium (TiIV), with the trivalent TiIIIPOs less explored because of instability and obstacles in synthesis. In this study, we used a simple synthetic strategy and prepared three new TiIIIPOs with different phosphorus oxoanions: the phosphate Ca2Ti(HPO4)2(PO4)·H2O (1), the phosphite CaTi2(H2O)(HPO3)4·H2O (2), and the hypophosphite Ti(H2PO2)3 (3). Each possesses different structures in one, two, and three dimensions, yet they are related to one another because of their infinite chains. Compound 1 exhibits proton-coupled electron transfer (PCET) reactivity in a solid state, losing one proton from its own HPO4 in oxidation to yield Ca2Ti(HPO4)(PO4)2·H2O (designated as 1O), while compound 2 also exhibits PCET reactivity in which the octahedral core [TiIII(H2O)]3+ gives off two protons to become a titanyl unit [TiIVâO]2+ under oxidation, yielding CaTi2O(HPO3)4·H2O (2O). Both 1O and 2O retain their original frameworks from before oxidation, but there are some changes in the hydrogen and Ti-O bonds that affect the IR absorption and powder X-ray diffraction patterns. Compound 3 represents the first titanium hypophosphite, and two polymorphs were discovered that show structures related to 1 and 2. This work demonstrates a simple strategy that is effective for preparing titanium(III) compounds in a pure phase; further, new findings in the pathways of solid-state PCET reactions promote a greater understanding of the self-sustaining oxidation behavior for TiIIIPO solid materials.
RESUMO
A novel titanium(iii) phosphite with intriguing polymorphism and solid-state proton-coupled electron transfer (PCET) oxidation is presented. The polymorphs show structure-dependent PCET reactivity, interpretable by proton distribution in channels. Combined with subsequent photoreduction, the redox cycle initiated with TiIII can produce H2 and transform organics.
RESUMO
Research has shown that permethrin, a Type-I pyrethroid, increases triglyceride (fat) accumulation in adipocytes. Little is known, however, about any similar effect of deltamethrin, a Type-II pyrethroid, which produces a distinct syndrome of poisoning in mammals compared with permethrin. This study was therefore aimed to explore the role of deltamethrin on fat accumulation in 3T3-L1 adipocytes and Caenorhabditis elegans. Deltamethrin (10 µM) significantly increased the fat accumulation in 3T3-L1 adipocytes and wild type C. elegans compared to respective controls. Deltamethrin decreased the ratio of phosphorylated AMP-activated kinase (pAMPKα) over AMPKα and phosphorylated acetyl-CoA carboxylase (ACC) over ACC, while it increased expression of CCAAT/enhancer-binding protein (C/EBPα) and peroxisome proliferator-activated receptor-γ (PPARγ) in 3T3-L1 adipocytes. Similarly, deltamethrin potentiated fat accumulation in C. elegans without affecting growth or pharyngeal pumping rate. Moreover, deltamethrin significantly reduced the total progeny number and locomotive activities in C. elegans in a dose-dependent manner. Deltamethrin increased fat accumulation via aak-2 (an ortholog of AMPKα) and nhr-49 (a homolog of peroxisome proliferator-activated receptor-α and also downstream target of aak-2) mediated mechanisms. The current work is the first report of the effects of deltamethrin on increased fat storage by 3T3- L1 adipocytes and C. elegans via aak-2 (AMPKα ortholog)-mediated mechanism.
