Browsing by Author "D'Vries, Richard Fernando"
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Item Chain-like uranyl-coordination polymer as a bright green light emitter for sensing and sunlight driven photocatalysis(Royal Society of Chemistry, 2020-07-02) Gomez, Germán E.; Onna, Diego; D'Vries, Richard Fernando; Barja, Beatriz C.; Alcides Ellena, Javier; Narda, Griselda Edith; Soler-Illia, G. J.A.A.A new uranyl-coordination polymer (UCP) has been solvothermally synthesized employing succinic acid and 1,10-phenanthroline (phen) as ligands. The obtained compound with the formula [(UO2)2(phen)(succ)0.5(OH)(O)4(μ3-O)(H2O)]·H2O (UNSL-1) is classified as 1D chains showing I0O1 connectivity. Also, the asymmetric unit is composed of two hepta-coordinated uranyl centers: U1 is surrounded by five oxygen atoms from succinate, while U2 is surrounded by two nitrogen atoms from phen and three oxygen atoms from succinate ([U1O7] and [U2N2O5]). The secondary-building unit (SBU) is composed of a sharing edge tetrameric cluster linked with a succinate ligand in the [−1 0 1] direction. Besides, the chains are reinforced by π–π stacking interactions between the aromatic rings of the phen molecules to conform a 2D supramolecular arrangement. Moreover, photoluminescence experiments show strong green emission consistent with uranyl crystalline materials. Photophysical characterization was completed via low-temperature measurements (77 K) and recording the decay emission for calculating the lifetime (τobs) value. Regarding its multifunctional properties, a cation-sensing performance was achieved showing selective quenching toward iron ions in aqueous media. Finally, UNSL-1 was tested as an efficient water photocatalyst for dye degradation under simulated sunlight irradiation, exhibiting promising results for organic-pollutant water remediation.Item Multiple Reversible Dynamics of Pyrimidine Based Acylhydrazones(Wiley-VCH Verlag, 2020-05-08) Arango, Alejandra M.; Wist, Julien; Ellena, Javier Alcides; D'Vries, Richard Fernando; Chaur, Manuel N.We employed (Z)‐N'‐[phenyl(pyrimidin‐2‐yl)methylene]nicotinohydrazide (2) and (Z)‐4‐(dimethylamino)‐N'‐[phenyl(pyrimidin‐2‐yl)methylene]benzohydrazide (3) as cores of dynamic chemical systems whose different states are modulated, in a reversible fashion, through specific physical and chemical stimuli. The structure of the compounds was determined by Nuclear Magnetic Resonance (NMR) techniques (1D and 2D) and confirmed by single‐crystal X‐ray diffraction. By Variable temperature (VT) 1H NMR experiments and DFT calculations, the conformational isomerism of 2 was studied and added as an additional input for the dynamic system. Additionally, 2 exhibits configurational E/Z isomerization mediated by pH variations and UV light. On the other hand, configurational isomerism locks an unlocks a tridentate pocket for metal cation coordination in both 2 and 3. All the different dynamic states configurational/conformational isomerism and locked and unlocked coordination constitute a development in the field of systems of multiple dynamics suitable for molecular machines.Item Synthesis, characterization, and redox potential properties of a new double-stranded Ni-bis(hydrazone)-based helicate(Academic Press Inc., 2020-08-25) Villada, Juan D.; Carmona Vargas, Christian C.; Alcides Ellena, Javier; Ayala, Alejandro P.; Ramírez Pradilla, Juan S.; Combariza, M. Y.; Galarza, Esperanza; D'Vries, Richard Fernando; Chaur, Manuel N.Herein we report the synthesis and structural characterization of a new Ni-bis(hydrazone) complex with the chemical formula [Ni2(L)2(Cl)2](Cl)2·2H2O (L = 2-(heptylthio)-4,6-bis(2-((E)-pyridin-2-ylmethylene)hydrazineyl)pyrimidine). Suitable crystals for X-ray diffraction showed the supramolecular interactions of this complex to exhibit a helical structure coordinating two Ni2+ metal ions bounded by two 2-(heptylthio)-4,6-bis(2-((E)-pyridin-2-ylmethylene)hydrazineyl)pyrimidine ligands. In addition, exploitation of the electrochemical properties by cyclic voltammetry, for this helicate, showed catalyzing ability for the reduction of H+ to H2.