The direct reaction of 6-(3,5-dimethyl-1H-pyrazol-1-yl)pyridazine-3-carboxylic acid (Me2LCOOH) with [(C4H8O)(CO)(3)Re(mu-Br)(2)Re(CO)(3)(OC4H8)] in dimethylformamide using a modified method produced a mixture of the known yellow [(N,N-Me2LCOOH)Re(CO)(3)Br] complex and a new red [(N,O-Me2LCOOH)Re(CO)(3)Br] isomer in a similar to 3:1 ratio. Structural analysis of the latter (Triclinic, P1, a = 7.418(3) & Aring;; b = 11.525(5) & Aring;; c = 12.241(5) & Aring;; alpha = 103.188(15)degrees, beta = 94.282(15)degrees, gamma = 97.647(15)degrees) indicates a twisted pyrazolyl group defining a 17.8(4)degrees dihedral angle with pyridazine. DFT modeling shows the N,O-coordination lowers the HOMO-LUMO gap from 2.65 to 2.28 eV compared to N,N-mode, consistent with the observed redshift of the MLCT absorption band. This effect arises from the pi-donating carboxylate oxygen destabilizing HOMO, while LUMO energies remain similar. MLCT emission bands appear at comparable energies, but N,O-coordination quenches radiative decay, reducing emission quantum yield by nearly two orders of magnitude versus the N,N-complex. Both complexes photosensitize singlet oxygen, confirming (MLCT)-M-3 emission character. Specific interactions with dimethylformamide likely enhance emission and singlet oxygen generation, especially for the N,N-complex.

This work reports the thermometric properties of a heterodinuclear Yb-Er complex, [{Yb(tta)3}(& micro;2-bpm){Er(tta)3}] (1) (tta- = thenoyltrifluoroacetonate and bpm = 2,2'-bipyrimidine), together with the corresponding homodinuclear analogues [{Ln(tta)3}2(& micro;2-bpm)] (Ln = Yb(2), Er(3)). Under 394 nm excitation, complex 1 enables temperature sensing over the 12-310 K range using three luminescence intensity ratio (LIR) readouts based on Yb3+ and Er3+ emissions, while complexes 2 and 3 provide single-ion-based thermometric responses. Among these, the Yb3+ (2F5/2 -> 2F7/2)/Er3+(4I13/2 -> 4I15/2) LIR yields the highest relative thermal sensitivity for 1, with a maximum value (Sm) of 2.5% K-1 at 12 K, and 1.0% K-1 at 310 K. Importantly, 1 represents the first heterodinuclear Yb-Er complex exhibiting thermometric properties and, more remarkably, enabling temperature sensing through three distinct LIR-based readouts. The Yb-only complex 2 exhibits Sm = 3.6% K-1 at 110 K, among the highest reported for Yb3+ molecular thermometers, while Er-based readouts in 1 and 3 provide moderate sensitivities at higher temperatures. Comparative analysis highlights the role of Yb3+ -> Er3+ energy transfer in modulating the thermometric behaviour of the heterodinuclear complex. Theoretical calculations support the presence of metal-metal and ligand-mediated energy-transfer pathways, which contribute to the observed temperature-dependent luminescence response.

The crystal structure of the title rhenium(I) complex [ReCl(C 7 H 5 BrN 4 )(CO) 3 ]·C 3 H 7 NO or fac -[(pypyrBr-κ 2 N , N )Re(CO) 3 Cl]·DMF [pypyrBr = 3-bromo-6-(1 H -pyrazol-1-yl)pyridazine] is reported. The compound was synthesized by reacting Re(CO) 5 Cl with pypyrBr [3-bromo-6-(1 H -pyrazol-1-yl)pyridazine] in toluene under reflux, yielding orange crystals upon purification and crystallization. Structural analysis reveals a distorted octahedral coordination environment around the Re I center, comprising three facial carbonyl ligands, one chloride, and the bidentate pypyrBr ligand. The ligand exhibits near planarity with minimal torsional deviation, and the N—Re—N bite angle is 73.50 (12)°. The complex crystallizes as a 1:1 dimethylformamide solvate, consolidated by hydrogen bonding between DMF and the ligand. A Cambridge Structural Database search confirmed the novelty of this structure, as no prior reports exist for pypyrBr or its metal complexes. Spectroscopic characterization ( 1 H NMR, 13 C NMR, IR) and elemental analysis support the proposed structure. This work expands the family of rhenium(I) tricarbonyl complexes with pyrazolyl-pyridazine ligands, relevant for photophysical and coordination chemistry applications.

This work reports the synthesis, characterization, and systematic study of fac-[Re(CO)3(Ip)Br] with imidazo-phenanthroline (Ip) ligand derivatives (2a-2d), whose optical properties can be tuned by changes in pH. UV-Vis and photoluminescence studies revealed pronounced pH-dependent spectral shifts and intensity changes. Ground-state acid-base titrations showed Ip deprotonation across the series, yielding pKa2 in the range of 9.77-10.89, while the complex 2b displays an additional pKa1 of 3.75 (-NH2 → NH3+). Complexes 2a/2c possess photoluminescence quantum yields of less than 1%. The photoluminescence response for amine complex 2b/2d is weaker than that of 2a/2c and depends on the excitation wavelength and pH, indicating mixed MLCT/ILCT contributions. TD-DFT, including spin-orbit coupling (SOC-TDDFT), shows that acid-base perturbations change the frontier orbital composition and SOC, where the protonation of -NH2 increases the SOC and stabilizes the 3MLCT emission for [2b]+ and [2d]+. In contrast, Ip deprotonation results in the triplet being localized on the ligand (3ILCT) (low ZFS), promoting emission deactivation by a PET process in basic media ([2a]-, [2b]-, [2c]-, and [2d]-). These results provide experimental and computational support for the photochemical tuning of MLCT/IL/ILCT transitions with pH, contributing to the design of new molecular tools for colorimetric and photoluminescent pH sensing based on Re(I)-Ip complexes.

The crystal structure of the title rhenium(I) complex [ReCl(C7H5BrN4)(CO)(3)]center dot C3H7NO or fac-[(pypyrBr-kappa N-2,N)Re(CO)(3)Cl]center dot DMF [pypyrBr = 3-bromo-6-(1H-pyrazol-1-yl)pyridazine] is reported. The compound was synthesized by reacting Re(CO)(5)Cl with pypyrBr [3-bromo-6-(1H-pyrazol-1-yl)pyridazine] in toluene under reflux, yielding orange crystals upon purification and crystallization. Structural analysis reveals a distorted octahedral coordination environment around the Re-I center, comprising three facial carbonyl ligands, one chloride, and the bidentate pypyrBr ligand. The ligand exhibits near planarity with minimal torsional deviation, and the N-Re-N bite angle is 73.50 (12)degrees. The complex crystallizes as a 1:1 dimethylformamide solvate, consolidated by hydrogen bonding between DMF and the ligand. A Cambridge Structural Database search confirmed the novelty of this structure, as no prior reports exist for pypyrBr or its metal complexes. Spectroscopic characterization (H-1 NMR, C-13 NMR, IR) and elemental analysis support the proposed structure. This work expands the family of rhenium(I) tricarbonyl complexes with pyrazolyl-pyridazine ligands, relevant for photophysical and coordination chemistry applications.

The crystal structure of the title rhenium(I) complex [ReCl(C7H5BrN4)(CO)3]·C3H7NO or fac-[(pypyrBr-κ2 N,N)Re(CO)3Cl]·DMF [pypyrBr = 3-bromo-6-(1H-pyrazol-1-yl)pyridazine] is reported. The compound was synthesized by reacting Re(CO)5Cl with pypyrBr [3-bromo-6-(1H-pyrazol-1-yl)pyridazine] in toluene under reflux, yielding orange crystals upon purification and crystallization. Structural analysis reveals a distorted octa-hedral coordination environment around the ReI center, comprising three facial carbonyl ligands, one chloride, and the bidentate pypyrBr ligand. The ligand exhibits near planarity with minimal torsional deviation, and the N-Re-N bite angle is 73.50 (12)°. The complex crystallizes as a 1:1 di-methyl-formamide solvate, consolidated by hydrogen bonding between DMF and the ligand. A Cambridge Structural Database search confirmed the novelty of this structure, as no prior reports exist for pypyrBr or its metal complexes. Spectroscopic characterization (1H NMR, 13C NMR, IR) and elemental analysis support the proposed structure. This work expands the family of rhenium(I) tricarbonyl complexes with pyrazolyl-pyridazine ligands, relevant for photophysical and coordination chemistry applications.

Three new rhenium phenanthroline tricarbonyl complexes were synthesized and fully characterized to examine changes in their photophysical properties and spectroscopic behavior in the presence of metal ions. To achieve this, the complexes were designed with modifications in both the phenanthroline and the axial ligand. The 4,7-dichloro-1,10-phenanthroline (Cl2phen) 2 phen) precursor was functionalized with two units of 1-aza-15-crown-5 (1A15C5) to obtain the complex [Re((A15C5)2phen)(CO)3Br] 2 phen)(CO) 3 Br] (1) 1 ) with the aim to study the spectroscopic perturbations induced by the binding of the metal ions by this receptor. Interestingly, the rhenium complex 1 shows a particular behavior towards Hg(II) and Pb(II), as a result of the halide abstraction assisted by these metal ions. Additionally, in the presence of Cu(II) the interaction and coordination/binding with the macrocycle cavities is also presumed. The chemical reaction assisted by Hg(II) was confirmed by changes in the absorption, emission and FT-IR spectra of [Re(Cl2phen)(CO)3Br] 2 phen)(CO) 3 Br] (2) 2 ) in presence of the heavy metal ion. These obtained profiles had similar patterns to the ones shown by the cationic complex [Re(Cl2phen)(CO)3(CH3CN)]PF6 2 phen)(CO) 3 (CH 3 CN)]PF 6 (3). 3 ). As final confirmation, this last complex was also studied in the presence of metal ions and its spectra remained unaltered.

We performed an extensive study on the most stable structures, the electronic properties, and the thermal stability of the 2D biphenylene sheet decorated with Li atoms. Our structural results show that the Li storage capacity of biphenylene is much higher than that recently reported, which increases the interest in this 2D material as a promising anode material for Li-ion batteries, although Li diffusion is not expected at room temperature. Moreover, we found striking phenomena that had not been detected yet, such as the formation of Li zigzag wires and metallic Li monolayers on the biphenylene sheet beyond a certain coverage threshold. In our calculations, we use high-level density-functional theory, quantum chemical topology analysis, and ab initio molecular dynamics simulations. In particular, the latter methodology allows for confirming the stability of the predicted Li-decorated biphenylene structures at room-temperature conditions.

In this work, we describe the synthesis, characterization, and spectroscopic properties of four new rhenium(I) tricarbonyl complexes bearing a pyridyl imidazole-naphthoquinone (Py-Im-Nq) ligand. The spectroscopic, X-ray, and electrochemical analyses confirm the formation of neutral complexes in all cases. Although the Py-Im-Nq ligand possesses two distinct chelating fragments, we observed a selective formation of the N,N-isomer rather than the N,O-coordination. EDA calculations revealed that the origin of the N,N-linkage isomerism results from more favorable electrostatic interactions present in the N,N-coordination. Furthermore, EDA-NOCV analysis indicated that the bonding situation in these complexes can be described by the Dewar-Chatt-Duncanson model, providing a quantitative characterization of the donation and back-donation interaction components in these complexes. Finally, we examined the spectroscopic behavior (UV-vis and photoluminescence) of these new rhenium(I) complexes in solution. The characterization of the excited states was performed using TD-DFT and density difference isosurfaces. It was found that, in contrast to typical fac-[Re(NN)(CO)3L]0/+ systems, the low-lying transitions exhibit intraligand (IL) character, with charge transfer predominantly occurring from the imidazole ring to the carbonyl group in the quinone moiety. In contrast, a mixed metal-to-ligand charge transfer (MLCT)/IL transition is assigned to the electronic excitation at shorter wavelengths.

Examples of molecular complexes acting as thermometers operating at room temperature in near infrared region are scarce, therefore this work showcases the anti-thermal quenching effect on neodymium(III) molecular thermometers working in biological windows within the physiological temperature range. A mononuclear complex, [Nd(L)(NO3)3] (1Nd), where L is a macrocyclic ligand, was synthesized and used as a precursor to develop two novel species: a dinuclear, [(Nd(L)(NO3))2(µ-BDC)](NO3)2·H2O (2Nd), linked by 1,4-benzenedicarboxylate (BDC), and a hexameric, [(Nd(L))(µ-BTC)(H2O)]6·35H2O (6Nd), linked with 1,3,5-benzenetricarboxylate (BTC). Thermometric properties were studied in the physiological temperature range (292-332 K), utilizing 804 nm laser excitation (first biological window) and monitoring emissions in the second biological window (908, 1065, and 1340 nm) associated with the 4F3/2 → 4I9/2, 4I11/2, 4I13/2 transitions, respectively. Among the complexes, the hexamer 6Nd exhibited exceptional performance, with Sr of 2.4%K-1 at 293 K, when luminescence intensity ratio (LIR) of two Stark components of the 4F3/2 → 4I11/2 emission was used, positioning it as a high-performance NdIII-based thermometer. All complexes displayed anti-thermal quenching behavior, surpassing the current molecular-based thermometers in the near-infrared region. Theoretical calculations using complete active space self consistent field (CASSCF) and Boltzmann population models between Kramers doublets of the 4F3/2 level were performed to rationalize the anti-thermal behavior.

Introducción: el edema de Reinke es la acumulación de fluidos en la capa externa de la lámina propia de las cuerdas vocales. Produce disfonía y raras veces obstrucción respiratoria. Las etiologías más frecuentes son el tabaquismo, el reflujo gastroesofágico y el mal uso y abuso vocal. Objetivos: determinar, mediante tratamiento quirúrgico, la tasa de resolución de la disnea inspiratoria severa provocada por edema de Reinke bilateral de cuerdas vocales. Diseño: estudio descriptivo y retrospectivo. Material y métodos: revisión de las historias clínicas electrónicas de todos los pacientes que consultaron y fueron tratados por disnea inspiratoria severa provocada por edema de Reinke bilateral de las cuerdas vocales, en el servicio de Otorrinolaringología del Hospital Italiano de Buenos Aires, entre febrero de 2007 y abril de 2015. Resultados: fueron tratados 4 pacientes de sexo femenino que consultaron por disnea inspiratoria severa. Fumaban más de 30 cigarrillos por día. La técnica quirúrgica consistió en resecar todo el edema polipoideo en forma bilateral, preservando el borde libre de las cuerdas vocales. Conclusiones: el edema de Reinke obstructivo es una patología infrecuente. La tasa de resolución de la disnea inspiratoria severa en las cuatro enfermas tratadas fue del100%. La resección total del edema y de la mucosa excedente, preservando un pequeño sector para que recubra el borde libre de la cuerda vocal (cordectomía vs. cordotomía), fue la técnica quirúrgica preferida

Zileuton is the only FDA-approved 5-lipoxygenase (5-LOX) inhibitor for asthma treatment, but it produces hepatotoxicity associated with the benzothiophene fragment. Using the concept of organometallic derivatization pioneered by Jaouen and Brocard, we synthesized five new organometallic Zileuton derivatives, maintaining the urea fragment and incorporating ferrocenyl and ruthenocenyl moiety (3a-e). Their biological activity was evaluated against 5-LOX, 15-LOX, COX-1, and COX-2 enzymes. The ferrocenyl and ruthenocenyl N-hydroxyurea complexes coined Ferroleuton (3a) and Ruthenoleuton (3e) showed the highest selective inhibitory activity against 5-LOX, with IC50 values of 0.21 ± 0.12 and 3.49 ± 1.11 μM, respectively. Notably, 3a exhibited superior activity compared to Zileuton (IC50 0.67 ± 0.09 μM), demonstrating the key role of N-hydroxyurea and ferrocenyl fragments in the inhibitory process. Worthy of note, both compounds displayed low cytotoxicity in lung fibroblast healthy cells line (MRC-5) (CC50 of 116.40 and >200 μM, respectively). Enzyme kinetic studies indicated competitive and mixed types of inhibition for 3a and 3e, respectively. Additionally, they demonstrated superior antioxidant capacity compared to Zileuton (DPPH, ABTS, and FRAP assays). Electrochemical and molecular dynamics (MD) studies suggest a chelating-redox deactivation mechanism for 5-LOX. These findings position Ferroleuton (3a) and Ruthenoleuton (3e) as promising candidates for inflammatory disease treatment.

The synthesis of four ferrocenylphosphine-amino acid ligands, (S)-(eta(5)-C5H4-PR2)Fe(eta(5)-C5H4-AA) [R= Ph, AA= l-Glu(OMe)(2): 5a'; R= Cy, AA= l-Glu(OMe)(2): 5b'; R= Ph, AA= l-Pro(OMe): 5a''; R= Cy, AA= l-Pro(OMe): 5b''] through a new synthetic method is presented along with two solid-state X-ray crystal structures of the corresponding phosphine selenides 5a''(Se) and 5b''(Se). Electronic and basicity properties of the ligands were evaluated through the synthesis of the corresponding phosphine selenides 5a'(Se) - 5b''(Se). Coordination capabilities of the ferrocenylphosphine-amino acid ligands with the p-cymene ruthenium dichloride dimer was evaluated, affording four neutral complexes, RuCl2(eta(6)-C10H14){PR2-[(eta(5)-C5H4)Fe(eta(5)-C5H4-AA)]} [R= Ph, AA= l-Glu(OMe)(2): 6a'; R= Cy, AA= l-Glu(OMe)(2): 6b'; R= Ph, AA= l-Pro(OMe): 6a''; R= Cy, AA= l-Pro(OMe): 6b''] and three cationic complexes < RuCl(NCMe)(eta(6)-C10H14){PR2-[(eta(5)-C5H4)Fe(eta(5)-C5H4-AA)]}> SbF6 [R= Ph, AA= l-Glu(OMe)(2): 7a'; R= Ph, AA= l-Pro(OMe): 7a''; R= Cy, AA= l-Pro(OMe): 7b'']. All new ligands and complexes were fully characterized by NMR spectroscopy, electrospray ionization mass spectrometry and their electrochemical properties were measured by cyclic voltammetry at a platinum disk electrode.

A protocol to correct ab initio calculated luminescence spectra of NdIII complexes is proposed. The emission spectrum of [NdIII(bipy)(tta)3] was measured to calibrate the optimal correction for the Racah parameters on top of a CASSCF calculation to attain the best energetic placement of the 4F3/2 → 4I13/2-9/2 emission lines. As interelectronic repulsion is the most important source of error in this calculation, this straightforward correction results in an accurate placement of transitions, allowing the assignment of a complex spectral shape in terms of its underlying transitions. Finally, the correction derived for [NdIII(bipy)(tta)3] was directly applied to a different NdIII complex, demonstrating the broad use of this approach.

This work reports the synthesis and characterization of ruthenium(II) complexes containing nitrogen -phosphorus -nitrogen (NPN) ligands, with L1 =N -(phenyl (pyridin-2-ylamino)phosphino)pyridin-2-amine and L2 = 4-methyl-N-((4-methylpyridin-2-ylamino)(phenyl)phosphino)pyridin-2-amine. The ruthenium complexes RuCl 2 PPh 3 (L1) ( 1 ) and RuCl 2 PPh 3 (L2) ( 2 ) show high activities in catalytic transfer hydrogenation of different substituted benzylideneanilines, with turnover frequencies up to 5882 h -1 and 5294 h -1 , respectively. The RuCl(CO)PPh 3 (L1) ( 3 ) and RuCl(CO)PPh 3 (L2) ( 4 ) complexes were non -active in the reaction studied. Theoretical calculations conducted for complex 4 showed that the carbonyl group promotes sigma-orbital interactions and backdonation phenomena from the metal centre to the pi* orbitals in the CO ligand, presenting a strong orbital contribution. This supports the hypothesis that complexes 3 and 4 are less reactive species and therefore present poor or null catalytic performance in the reaction studied.

Icosahedral Ni13@Ag42 is a stable nanoparticle formed by a magnetic nickel core surrounded by a silver coating that provides physical protection to the 3d metal cluster as well as antibacterial properties. In this work, we report density functional theoretical calculations to delve into a comprehensive analysis of how surface oxidation impacts the structural, electronic, magnetic, and reactivity properties of this interesting nanoparticle. To elucidate the role played by the silver coating, we compare the results with those found for the bare Ni13 cluster also subjected to surface oxidation. When Ni13 is covered by silver, we find a markedly robust behavior of the magnetic moment of the resulting nanoparticle, which remains nearly constant upon oxidation up to the rates explored, and the same holds for its overall reactivity. The obtained trends are rationalized in terms of the complex interplay between Ni-Ag and Ag-O interactions which impact the relative inter-atomic distances, charge transfer effects, spin polarization and magnetic couplings.

This work describes the synthesis and evaluation as catalysts of two ruthenium(II) complexes, RuC1 and RuC2, containing NPN ligands=(N-(phenyl(pyridin-2-ylamino)phosphino)pyridin-2-amine and 2-((phenyl(pyridin-2-ylmethyl)phosphino)methyl)pyridine, respectively) for furfural and hydroxymethylfurfural hydrogenation. The catalysts displayed exceptional activity under mild conditions (180 °C, 40 bar H2) achieving over 98 % conversion and 98–99 % selectivity towards furfuryl alcohol (from furfural) and bis(hydroxymethyl)furan (from hydroxymethylfurfural) within 30 min, using a substrate-catalyst ratio of 3000:1. Remarkably, the catalysts maintained their efficacy even at a tenfold higher substrate loading (10,000:1), albeit with extended reaction times (3 and 4 h for furfural and hydroxymethylfurfural, respectively). Turnover frequencies (TOFs) were impressive, reaching 3920 h−1 and 3200 h−1 for furfural hydrogenation with the catalyst RuC1 and RuC2, respectively. Similarly, TOFs for hydroxymethylfurfural hydrogenation were 2450 h−1 and 2475 h−1 for RuC1 and RuC2, respectively. Notably, the catalysts exhibited excellent stability under reaction conditions. These findings demonstrate the promising potential of RuC1 and RuC2 for efficient hydrogenation of biomass-derived furans, offering a sustainable approach for the production of valuable bio-based chemicals.

By combining density-functional theory and a quantum-thermodynamic model, we compute the usable hydrogen storage capacities of slit pores formed by two Li-decorated layers of the strongly anisotropic Pmmn8 borophene sheet. Our results show the important role played by the rotational degree of freedom of the hydrogen molecule in determining the confining potential within the slit pores and their hydrogen storage capacities. A remarkable finding is that for small pore widths of around 6 & Aring;, the usable volumetric capacity of these borophene-based adsorbents at room temperature reaches the target stipulated by the U.S. Department of Energy for a quite low loading pressure of about 6 MPa when the depletion pressure is set to 0.1 MPa, which could be very useful for practical applications. Our results also show that a good usable gravimetric capacity can be reached only when the pore widths are of at least 30 & Aring;, and operating at very large loading pressures of at least 60 MPa and temperatures lower than 100 K.

The combined action of singlet oxygen (1O2) and photoinduced carbon monoxide (CO) released by tricarbonyl metal complexes is a promising synergic treatment against multi-resistant bacterial infections. In this work, we explore the use of a polydentate ligand (bpm = 2,2-bipyrimidine) that offers the opportunity to accommodate two metal centers exhibiting both, singlet oxygen generation and carbon monoxide releasing properties in a single molecule. A series of monometallic ([(bpm)M(CO)3Br]; M = Mn, Re) and homo or hetero bimetallic ([Br(CO)3M(bpm)M'(CO)3Br]; M = Mn, Re) compounds were synthesized in moderate to good yields by modulating the metal precursor or the stoichiometry, also the syn:anti isomers ratio for the bimetallic complexes was dependent on the experimental conditions used. DFT modelling shows the anti -isomer is more stable than the syn -isomer by less than 8 kJ mol-1, which is consistent with those experimentally observed in terms of majority product and the effect of experimental conditions over the anti-syn ratio. The HOMO-LUMO gap is lower for the mono and bimetallic rhenium(I) compounds compared to the values for the manganese(I) analogues, while the heterometallic complex shows intermediate values for the anti- isomer. The photophysical characterization shows typical absorption and emission bands with MLCT character. In addition, CO-release and 1O2 generation quantum yields were evaluated for the monometallic Mnbpm and Rebpm homologues and compared with values obtained for the homo- and hetero-bimetallic complexes. Interestingly the replacement of a Mn(CO)3Br moiety in MnbpmMn by a Re(CO)3Br one makes the heterometallic MnbpmRe molecule a molecular oxygen sensitizer and partially retaining its carbon monoxide releasing ability.