Publications by authors named "Leonardo F Serafim"

Flavor esters are organic compounds widely used in the food industry to enhance the aroma and taste of products. However, most chemical processes for the production of these flavoring compounds use toxic organic solvents. Some organic solvents derived from petroleum can leave behind residual traces in food products, which may raise concerns about potential health risks and contamination.

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The synthesis and structures of nitrile complexes of V(N[Bu]Ar), (Ar = 3,5-MeCH), are described. Thermochemical and kinetic data for their formation were determined by variable temperature Fourier transform infrared (FTIR), calorimetry, and stopped-flow techniques. The extent of back-bonding from metal to coordinated nitrile indicates that electron donation from the metal to the nitrile plays a less prominent role for than for the related complex Mo(N[Bu]Ar), .

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The selective hydrolysis of the extremely stable phosphoester, peptide and ester bonds of molecules by bio-inspired metal-based catalysts (metallohydrolases) is required in a wide range of biological, biotechnological and industrial applications. Despite the impressive advances made in the field, the ultimate goal of designing efficient enzyme mimics for these reactions is still elusive. Its realization will require a deeper understanding of the diverse chemical factors that influence the activities of both natural and synthetic catalysts.

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Article Synopsis
  • - Steady-state fluorescence spectroscopy is useful in biophysics and imaging but has limitations in the information it provides about complex systems like DNA and amyloid fibrils.
  • - This study utilizes time-resolved spectroscopy to uncover two distinct binding sites for ruthenium complexes on amyloid-β fibrils, revealing previously hidden interactions that steady-state methods missed.
  • - Understanding these binding interactions is crucial for developing drugs that target amyloid proteins and mitigate their harmful effects, with time-resolved spectroscopy serving as a valuable method for studying these dynamics.
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Due to the numerous failed clinical trials of anti-amyloid drugs, microtubule associated protein tau (MAPT) now stands out as one of the most promising targets for AD therapy. In this study, we report for the first time the structure-dependent MAPT aggregation inhibition of carbon nitride dots (CNDs). CNDs have exhibited great promise as a potential treatment of Alzheimer's disease (AD) by inhibiting the aggregation of MAPT.

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In this study, chemical promiscuity of a binuclear metallohydrolase aminopeptidase (AP) has been investigated using DFT calculations. AP catalyzes two diverse reactions, peptide and phosphoester hydrolyses, using its binuclear (Zn-Zn) core. On the basis of the experimental information, mechanisms of these reactions have been investigated utilizing leucine -nitro aniline (Leu-NA) and bis(4-nitrophenyl) phosphate (BNPP) as the substrates.

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  • Photocatalytic degradation of water pollutants is gaining importance to safeguard water resources and tackle diseases, yet many metal-based photocatalysts display low efficiency and create secondary pollution risks.
  • This study highlights the superior photocatalytic activity of gel-like carbon dots (G-CDs), which outperformed most known carbon dot species and demonstrated efficiency comparable to graphitic carbon nitride (g-CN).
  • The addition of g-CN to G-CDs (creating CD-CN) increased the photocatalytic rate constant and showcased its synergistic effects, while also proving to be non-toxic and environmentally friendly, making G-CDs a promising option for future water purification applications.
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Gram-negative bacteria are some of the biggest threats to public health due to a large prevalence of antibiotic resistance. The difficulty in treating bacterial infections, stemming from their double membrane structure combined with efflux pumps in the outer membrane, has resulted in a much greater need for antimicrobials with activity against these pathogens. Tunicate host defense peptide (HDP), Clavanin A, is capable of not only inhibiting Gram-negative growth but also potentiating activity in the presence of Zn(II).

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Reaction of [Pd(IPr)] (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) and O leads to the surprising discovery that at low temperature the initial reaction product is a highly labile peroxide complex cis-[Pd(IPr)(η-O)]. At temperatures ≳ -40 °C, cis-[Pd(IPr)(η-O)] adds a second O to form trans-[Pd(IPr)(η-O)]. Squid magnetometry and EPR studies yield data that are consistent with a singlet diradical ground state with a thermally accessible triplet state for this unique bis-superoxide complex.

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