Infraspecific Chemical Variability and Metabolomic Profiling by Paper Spray Ionization (PSI-MS) of Averrhoa carambola from Different Brazilian Biomes.

This research focused on the molecular diversity of A. carambola collected from three Brazilian biomes (Cerrado, Amazônia, and Mata Atlântica), whose results revealed significant differences in metabolite profiles among these biomes through PSI-MS analysis. Chemometric analysis provided valuable insights into the clustering patterns and metabolic distinctions. Cerrado and Mata Atlântica biomes exhibited a 70 % similarity, indicating a notable degree of resemblance. In Cerrado, carambolaside A was notably abundant, while carambolaside M was low in Amazônia and moderate in Cerrado samples. Carambolaside B was abundant in Amazônia but relatively low in the Cerrado and Mata Atlântica. In contrast, the Amazônia biome samples appeared to be more dissimilar. In Cerrado, epicatechin, kaempferol, and procyanidin B showed lower abundance, while apigenin, quercetin, myricetin, and rutin displayed moderate levels. Mata Atlântica showed relatively higher levels of kaempferol, quercetin, and rutin. This study indicated the environmental influence on secondary metabolites production in A. carambola fruits.

A giant hybrid organic-inorganic octahedron from a narrow rim carboxylate calixarene.

Here we discovered an unprecedented giant octahedral coordination compound bearing 16 Zn2+, 12 Na+, 8 O2-, 4 OH-, 13 H2O and 6 L4- ligands [L4- = fully deprotonated tetra(carboxymethoxy)calix[4]arene]. Its structure was elucidated by single-crystal X-ray diffraction, wavelength-dispersive X-ray spectroscopy and MALDI-TOF mass spectrometry. This compound, Zn8Na6L6⊃Zn8Na6O8(OH)4(H2O)13 (external⊃internal), has eight tetrahedral zinc ions forming the coordination vertices of an outermost cube where carboxylate groups from the sodium calixarenes are anchored. Its core consists of eight Zn2+, six Na+, eight O2-, and four OH- distributed over three layers, besides thirteen coordinated H2O molecules.

Palladium-catalyzed tandem Heck-lactonization from o-iodophenols and enoates: synthesis of coumarins and the study of the mechanism by electrospray ionization mass spectrometry.

The tandem Heck-lactonization reaction between enoates Z-1a,b, E-1a, E-2a-d, Z-2e, 2f, and o-iodophenols (4a-f) was studied in the presence of substoichiometric amounts of Pd(OAc)(2) or PdCl(2), under experimental conditions favoring the cationic mechanism (conditions A, B, and C), leading to coumarins 5a-f and 6a-e. Moderate to excellent yields were obtained under aqueous conditions (conditions A and B). Using electrospray ionization for transferring ions directly from solution to the gas phase, and mass spectrometry for structural assignments, key cationic palladium intermediates have been successfully intercepted and structurally characterized for the first time for this type of reaction.