Rafael Moreno-Esparza

A combined experimental and theoretical study of the biphenyl (BP) crystal is presented. The X‐ray diffraction data collected at 100 K were subjected to Hirshfeld atom and multipole refinements of the electron density, ρ(r). A theoretical exploration of the potential energy surface (PES) of the crystal was also carried out. This investigation challenges the common assumption that the planar structure of BP in the phase I crystal is an average of two twisted configurations in a double‐well potential. The theoretical computations provide compelling evidence that this structure corresponds to a minimum on the PES hence to a stable molecular arrangement. Consistently, the experiment showed no evidence of positional or dynamic disorder. The intramolecular hydrogen‐hydrogen bonds detected are not repulsive. The topological analysis of the experimental and theoretical ρ(r) reveals that both the intra‐ and intermolecular H⋅⋅⋅H and the C−H⋅⋅⋅π contacts stabilize the BP crystal.

Background: Neuroblastoma is the main solid extracranial tumor of childhood. The amplification of N-myc oncogene (MYCN) and 1p deletion are the main molecular alterations. These features are what make treatment impossible, especially in high-risk patients with metastases. Materials and Methods: Our study investigated the processes undergone by CHP-212 neuroblastoma cells, after being treated with Casiopeínas® (Cas) IIgly, IIIEa, and IIIia for 2, 10, and 24 h. Results: At 2 h, all the treatments Ied to apoptosis [defined by the presence of B-cell lymphoma 2 (BCL2), BCL2-associated X protein, cytochrome c, and caspase-3]. In addition, autophagy with specific molecules beclin-1 and microtubule-associated protein 1A/1B-light chain 3 (LC3)-II/LC3-I (ratio >1). Later at 10 h, autophagy-associated proteins were observed, and at 24 h, only survival proteins nuclear factor kappa-light-chain-enhancer of activated B-cells (NF-κB), and extracellular signal-regulated kinases (ERK)2/ERK1>1 were found. Another relevant finding was the presence of caspase-10 throughout the study, especially in cells treated with CasIIgly and CasIIIEa. Conclusion: These relationships indicate a possible mechanism of action of Casiopeínas on neuroblastoma.

Compounds from the 2,2′-bipyridine molecular family were investigated for use as redox-active materials in organic flow batteries. For 156 2,2′-bipyridine derivatives reported in the academic literature, we calculated the redox potential, the pK_a for the second deprotonation reaction, and the solubility in aqueous solutions. Using experimental data on a small subset of derivatives, we were able to calibrate our calculations. We find that functionalization with electron-withdrawing groups leads to an increase of the redox potential and to an increase of the molecular acidity (as expressed in a reduction of the pK_a value for the second deprotonation step). Furthermore, calculations of solubility in water indicate that some of the studied derivatives have adequate solubility for flow battery applications. Based on an analysis of the phyisco-chemical properties of the 156 studied compounds, we down-select five molecules with carbonyl- and nitro-based functional groups, whose parameters are especially promising for potential applications as negative redox-active materials in organic flow batteries.

The aim of this study is to identify the influence of the ligand aminoacidato on the antiproliferative activity against human tumor cell lines HeLa, HCT-15 and SKL-U through the analysis of a set of Cu(II) coordination compounds with general formula [Cu(4,7-dimethyl-1,10-phenanthroline)(N-O)]NO3where N-O represents several essential aminoacids. Results show that the hydrophobicity of the amino acid ligands increases the cellular uptake of copper (II) in HeLa tumor cell line, however, the increase of copper concentration inside the cell is not enough to produce significant changes in antiproliferative activity in this tumor cell line. Thus, the substituents on diimine ligand apparently play the stronger role to control the activity of these complexes. Also molecular structures of compounds 2 (Cas IIala) and 4 (Cas IInva) are presented.

Calculations of structure, redox potential and spin transition energies were performed using DFT approximations for a series of [Fe(bztpen)OR] ^2+/+ type Fe ^III /Fe ^II systems (R=Me, Et, n Pr, n Bu), which have a temperature dependent spin crossover behavior. These compounds exhibit changes in redox and magnetic properties, related to structural variations quite important for their possible applications among which signal generator materials stand out. Functionals B3LYP, ωB97X−D and TPSS along with PCM solvation model were evaluated for redox potential, whereas for spin crossover the TPSSh functional was also included. The multireference character of these compounds was tested as well. Calculations were compared to experimental measurements, and ωB97X−D proved able to accurately describe the geometries observed in solid state for the low spin (LS) and high spin (HS) states; moreover, it had the best correlation between calculated and experimental redox potential values. However, in the description of the spin transition energies the TPSS functional is needed to correctly describe the LS state as the observed ground state in the complexes at low temperature, which allows to calculate proper spin transition curves as a function of temperature. From these results, we obtained suitable approximations for an accurate description of redox potential and magnetic properties for the Fe ^III coordination compounds, which can be extended to model similar systems.

The intermolecular interactions in C₆X₆–arene crystals (X = F, Cl) and the halogen substitution effect can be quantified by the electron density.

The highly stable nitrosyl iron(II) mononuclear complex [Fe(bztpen)(NO)](PF₆)₂ (bztpen=N‐benzyl‐N,N′,N′‐tris(2‐pyridylmethyl)ethylenediamine) displays an S=1/2↔S=3/2 spin crossover (SCO) behavior (T_1/2=370 K, ΔH=12.48 kJ mol⁻¹, ΔS=33 J K⁻¹ mol⁻¹) stemming from strong magnetic coupling between the NO radical (S=1/2) and thermally interconverted (S=0↔S=2) ferrous spin states. The crystal structure of this robust complex has been investigated in the temperature range 120–420 K affording a detailed picture of how the electronic distribution of the t_2g–e_g orbitals modulates the structure of the {FeNO}⁷ bond, providing valuable magneto–structural and spectroscopic correlations and DFT analysis.