The metal-organic frameworks of the formula Ln(bta)ÁnH 2 O where n = 3, 4, 5 or 6; bta = benzene-1,3,5triacetate ion: [C 9 H 9 (COO) 3 ] 3-; Ln = La(III), Nd(III), Eu(III), Tb(III), Ho(III), Tm(III), Lu(III) were synthesized by the reaction of LnCl 3 ÁxH 2 O with ammonium salt of H 3 bta acid in water solution. Insoluble water compounds crystallize in the monoclinic or triclinic crystal system, and they are stable up to 30°C. When heated, they decompose up to 160-200°C in two stages to stable anhydrous compounds. The dehydrated compounds Ln(bta) are still crystalline and stable up to about 350°C. When heated above 350°C, they undergo decomposition where the intermediate products are Ln 2 O 2 CO 3 or Tb 4 O 6 CO 3 and the residues are: Ln 2 O 3 or Tb 4 O 7. The interpretation of IR spectra of title compounds was made taking into consideration the experimental and theoretical wavenumbers obtained for H 3 bta specie. The XPS spectra of H 3 bta and its complexes were recorded. The way of metal-carboxylate group of ligand coordination was discussed. This work presents the results of the XPS analyses, which allowed to determine the binding energies (E b) for the main lines of Ln3d, Ln4d, Ln5p, C1s, O1s spectra, spin-orbital splitting and full width at half maximum complexes.
This manuscript describes a simple yet meaningful demonstration that can be easily adopted by highschool teachers to emphasize some potential dangers associated with gas inhalation. The demonstration aims to illustrate the undesirable effects of some gases on living organisms by employing freshly cut, colored flowers and ammonia gas. When in direct contact, the ammonia gas causes abrupt, easily observable changes in the appearances of the flowers, leading to their wilting, discoloration, or color fading. The experiment can be carried out at any time within an academic course because flowers with colorful petals can be easily obtained from any local store throughout the year. The proposed demonstration may also be used, if necessary, to introduce students into important biological and chemical concepts, including simple chemical calculations, the cell structure of flowers, and the effects of harmful gas molecules on living cells.
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