RESUMEN

In this contribution, we describe the preparation, characterization, and electrochemical behavior of a series of four new mononuclear M(II) complexes featuring a symmetric substituted N2O2-tetradentate Schiff base ligand, bearing either trifluoromethyl and p-bromophenyl (M = Ni, 3; Cu, 4) or trifluoromethyl and the π-extended p-(2-thienyl)phenylene (M = Ni, 5; Cu, 6) substituents. Complexes 3 and 4 were readily synthesized by reacting the diprotic fluorinated Schiff base proligand 2 with the appropriate hydrated metal(II) acetates, whereas 5 and 6 were obtained upon Stille cross-coupling reaction of 3 and 4 with 2-(tributylstannyl)-thiophene, respectively. Compounds 3-6 were isolated as neutral, air, and thermally stable-coloured solids, with yields ranging from 60 to 80%. The four complexes, the diimine precursor 1 and its trifluoroacetylated derivative 2, were identified using analytical (EA, ESI-MS), spectroscopic (IR, 1H, 13C, and 19F NMR), and X-ray crystallographic methods. X-ray crystal structure determination of complexes 3-5 revealed that both four-coordinate Ni(II) and Cu(II) metal ions adopt a square planar geometry. The magnetic properties of powdered samples of the Cu(II) derivatives 4 and 6 have been investigated (2-300 K) and found consistent in both cases with a single isolated copper(II) ion (s = 1/2). DFT calculations were used to examine the optimal geometries of complexes 5 and 6, allowing for a consistent perspective of their structure and characteristics. The primary aspects of the UV-vis spectra were interpreted using TD-DFT computations. Finally, electrochemical data indicate that complexes 5 and 6 polymerize at high anodic potentials in acetonitrile (greater than 2.0 V vs. Ag/AgCl). Cyclic voltammetry, scanning electron microscopy, and energy-dispersive X-ray spectroscopy (SEM-EDS) analyses were used to characterize the obtained films poly-5 and poly-6.

RESUMEN

We have recently reported a series of neutral square planar tridentate Schiff base (L) complexes of the general formula [(L)M(py)], showing relatively high first-order hyperpolarizabilities and NLO redox switching behavior. In the present study, new members of this family of compounds have been prepared with the objective to investigate their potential as building blocks in the on-demand construction of D-π-A push-pull systems. Namely, ternary nickel(II) building blocks of general formula [(LA/D)Ni(4-pyX)] (4-7), where LA/D stands for an electron accepting or donating dianionic O,N,O-tridentate Schiff base ligand resulting from the monocondensation of 2-aminophenol or its 4-substituted nitro derivative and ß-diketones R-C(=O)CH2C(=O)CH3 (R = methyl, anisyl, ferrocenyl), and 4-pyX is 4-iodopyridine or 4-ethynylpyridine, were synthesized and isolated in 60-78% yields. Unexpectedly, the Sonogashira cross-coupling reaction between the 4-iodopyridine derivative 6 and 4-ethynylpyridine led to the formation of the bis(4-pyridyl) acetylene bridged centrosymmetric dimer [{(LD)Ni}2(µ2-py-C≡C-py)] (8). Complexes 4-8 were characterized by elemental analysis, FT-IR and NMR spectroscopy, single crystal X-ray diffraction and computational methods. In each compound, the four-coordinate Ni(II) metal ion adopts a square planar geometry with two nitrogen and two oxygen atoms as donors occupying trans positions. In 8, the Ni…Ni separation is of 13.62(14) Å. Experimental results were proved and explained theoretically exploiting Density Functional Theory calculations.

RESUMEN

INTRODUCTION: Bronchiectasis is a very heterogeneous disease but some homogeneous groups with similar clinical characteristics and prognosis have been identified. Exacerbations have been shown to have a negative impact on the natural history of bronchiectasis. The objective of this study was to identify the definition and characteristics of the "frequent exacerbator patient" with the best prognostic value and its relationship with the severity of bronchiectasis. METHODS: A historical cohort of 651 patients diagnosed with bronchiectasis was included. They had all received 5 years of follow-up since their radiological diagnosis. Exacerbation was defined as a worsening of the symptoms derived from bronchiectasis that required antibiotic treatment. The main outcome was all-cause mortality at the end of follow-up. RESULTS: The mean age was 48.2 (16) years (32.9% males). 39.8% had chronic infection by Pseudomonas aeruginosa. Mean BSI, FACED, and E-FACED were 7 (4.12), 2.36 (1.68), and 2.89 (2.03), respectively. There were 95 deaths during follow-up. The definition of the "frequent exacerbator patient" that presented the greatest predictive power for mortality was based on at least two exacerbations/year or one hospitalization/year (23.3% of patients; AUC-ROC: 0.75 [95% CI: 0.69-0.81]). Its predictive power was independent of the patient's initial severity. The clinical characteristics of the frequent exacerbator patient according to this definition varied according to the initial severity of bronchiectasis, presence of systemic inflammation, and treatment. CONCLUSIONS: The combination of two exacerbations or one hospitalization per year is the definition of frequent exacerbator patient that has the best predictive value of mortality independent of the initial severity of bronchiectasis.

Asunto(s)

Bronquiectasia/mortalidad , Progresión de la Enfermedad , Índice de Severidad de la Enfermedad , Área Bajo la Curva , Argentina , Brasil , Bronquiectasia/clasificación , Bronquiectasia/microbiología , Chile , Estudios de Cohortes , Femenino , Hospitalización , Humanos , Estimación de Kaplan-Meier , Masculino , Persona de Mediana Edad , Fenotipo , Pronóstico , Pseudomonas aeruginosa , Curva ROC

RESUMEN

INTRODUCTION: In recent years, there has been an increasing number of clinical trials investigating the effect of pharmacological treatments on patients with bronchiectasis. Areas covered: This review provides an overview of current drugs used in bronchiectasis patients as well as those that could make a future contribution to the management of this disease. Expert commentary: Bronchiectasis is a very heterogeneous disease, so it can be studied from a phenotypic standpoint and its pathophysiological mechanisms (endotypes) can be defined. This provides an interesting field of research as it enables the identification of patients suitable for inclusion in specific clinical trials on new drugs.

Asunto(s)

Bronquiectasia/tratamiento farmacológico , Antibacterianos/uso terapéutico , Antiinflamatorios/uso terapéutico , Broncodilatadores/uso terapéutico , Expectorantes/uso terapéutico , Glucocorticoides/uso terapéutico , Humanos , Índice de Severidad de la Enfermedad

RESUMEN

Introducción: la oclusión traumática se define como una alteración en las relaciones oclusales del sistema masticatorio, lo cual podría ser un factor conducente a un proceso inflamatorio en el ligamento periodontal, en la pulpa dental, y en tejidos blandos sensitivos. Objetivo: identificar las afecciones pulpares de origen no infeccioso en órganos dentarios con oclusión traumática en pacientes de un hospital del sector público de Mérida, Yucatán, México. Métodos: se realizó un estudio observacional y analítico, en un hospital del sector público de Mérida, Yucatán, México (2014). La muestra estuvo constituida con un total de 156 órganos dentarios de 82 pacientes, de 20 y más años de edad, que presentaron oclusión traumática en dientes permanentes y que mostraron alguna afección en tejido pulpar de origen no infeccioso, de acuerdo con la clasificación de la Academia Americana de Endodoncia. También se incluyó a los pacientes que presentaban caries, fracturas, fisuras, obturaciones, endodoncia, ortodoncia o trauma dentoalveolar. Se empleó un muestreo No probabilístico, por conveniencia. Se obtuvo el consentimiento informado y voluntario, historia médica y dental, y se realizó la evaluación de los signos y síntomas de dolor, pruebas pulpares (térmicas y eléctricas), palpación y percusión y abordaje diagnóstico con tinción/transiluminación, así como pruebas oclusales con papel de articular y examinación e interpretación de radiografías periapicales. Se utilizó estadística descriptiva. Resultado: hubo ausencia de dolor en 53 por ciento de los 156 órganos dentarios estudiados. Las alteraciones radiográficas se presentaron en 63 por ciento: entre ellas los nódulos pulpares tuvieron el mayor porcentaje (25 por ciento). La pulpitis fue reversible en 37 por ciento (n= 58); la oclusión traumática más frecuente fue la maloclusión (n= 49). En los 156 órganos dentarios estudiados, el signo clínico que mostró mayor frecuencia fue el desgaste en esmalte (n= 56). Conclusiones: las afecciones pulpares de origen no infeccioso se presentaron en alto porcentaje de dientes permanentes de pacientes con oclusión traumática(AU)

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Introduction: Occlusal trauma is defined as an alteration in the occlusal relationships of the masticatory system, which may lead to inflammation of the periodontal ligament, the dental pulp and sensitive soft tissues. Objective: Iidentify non-infectious pulpal disorders in dental organs with occlusal trauma of patients from a public hospital in Mérida, Yucatán. Methods: An observational analytical study was conducted at a public hospital in Mérida, Yucatán, Mexico (2014). The study universe was 156 dental organs of 82 patients aged 20 years and over with occlusal trauma in permanent teeth and some degree of non-infectious pulp tissue disorder, based on the classification of the American Academy of Endodontics. Patients were also included who presented caries, fractures, fissures, fillings, endodontic treatment, orthodontic treatment or dentoalveolar trauma. Convenience non-probability sampling was applied. Voluntary informed consent was obtained. Medical and dental records were examined. An evaluation was carried out of pain signs and symptoms. Thermal and electric pulp tests were performed, as well as palpation, percussion and diagnostic staining/transillumination. Occlusal testing was conducted using articulating paper. Periapical radiographs were examined and interpreted. Descriptive statistics were used. Result: There was no pain in 53 percent of the dental organs studied. Radiographic alterations were present in 63 percent; the most common were pulp nodes (25 percent). Pulpitis was reversible in 37 percent (n= 58), and the most frequent occlusal trauma was malocclusion (n= 49). In the 156 teeth studied, the most common clinical sign was enamel wear (n= 56). Conclusions: Non-infectious pulpal disorders were present in a large number of permanent teeth of patients with occlusal trauma(AU)

Asunto(s)

Humanos , Masculino , Femenino , Adulto , Oclusión Dental Traumática/diagnóstico , Maloclusión , Enfermedades Periapicales/diagnóstico , Pulpitis , México , Modelos Teóricos , Estudio Observacional

RESUMEN

We report the synthesis, characterization, crystal structures, nonlinear-optical (NLO) properties, and density functional theory (DFT) calculations of nickel(ii) and copper(ii) complex based ONO tridentate Schiff base ligands: two mononuclear compounds, [Ni(An-ONO)(NC5H5)] (5) and [Cu(An-ONO)(4-NC5H4C(CH3)3)] (6), and two heterobimetallic species, [M(Fc-ONO)(NC5H5)] (M = Ni, 7; Cu, 8), where An-ONOH2 (3) and Fc-ONOH2 (4) are the 1 : 1 condensation products of 2-aminophenol and p-anisoylacetone and ferrocenoylacetone, respectively. These compounds were characterised by microanalysis, FT-IR and X-ray crystallography in the solid state and in solution by UV-vis and (1)H and (13)C NMR spectroscopy. The crystal structures of 3-5, 7 and 8 have been determined and show for Schiff base complexes 5, 7 and 8 a four-coordinated square-planar environment for nickel and copper ions. The electrochemical behavior of all derivatives 3-8 was investigated by cyclic voltammetry in dichloromethane, and discussed on the basis of DFT-computed electronic structures of the neutral and oxidized forms of the compounds. The second-order NLO responses of 3-8 have been determined by harmonic light scattering measurements using a 10(-2) M solution of dichloromethane and working with a 1.91 µm incident wavelength, giving rather high ß1.91 values of 350 and 290 × 10(-30) esu for the mononuclear species 5 and 6, respectively. The assignment and the nature of the electronic transitions observed in the UV-vis spectra were analyzed using time-dependent (TD) DFT calculations. They are dominated by LMCT, MLCT and π-π* transitions.

RESUMEN

The synthesis, spectroscopic and structural characterization, linear and nonlinear optical properties, as well as the electrochemical behavior of a series of robust neutral binuclear M[Fc-C(O)CH=C(CH(3))N-X-N=CH-(2-O,5-R-C(6)H(3))] (M = Ni (4), Cu (5), X = o-C(6)H(4), R = H; M = Ni (9), X = CH(2)CH(2), R = OH), and their corresponding ionic trinuclear [M{Fc-C(O)CH=C(CH(3))N-X-N=CH-(eta(6)-2-O,5-R-C(6)H(3))RuCp*}][PF(6)] (6, 7, 10), M[ONNO]-type unsymmetrical Salophen and salen complexes featuring ferrocenyl (Fc) donor and the mixed sandwich acceptor [Cp*Ru(eta(6)- salicylidene)](+) as a push-pull moiety are reported in this paper (Fc = CpFe(eta(5)-C(5)H(4)); Cp = eta(5)-C(5)H(5); Cp* = eta(5)-C(5)Me(5)). The single-crystal X-ray structure of the bimetallic iron-nickel derivative 4 indicates a bowed structure of the unsymmetrical Schiff base skeleton. The Ni(II) ion is tetracoordinated in a square planar environment, with two nitrogen atoms and two oxygen atoms as donors. The new metalloligand [Fc-C(O)CH=C(CH(3))N(H)CH(2)CH(2)N=CH-(2,5-(OH)(2)C(6)H(3))] (8) obtained from the Schiff base condensation of 2,5-dihydroxobenzaldehyde with the half-unit precursor, Fc-C(O)CH=C(CH(3))N(H)CH(2)CH(2)NH(2) (2), is reported with its crystal structure showing partial delocalization of the heteroconjugated [O-C-C-C-N] frameworks with a dihedral angle between the respective planes of 60.76 degrees. Second order nonlinear optical (NLO) measurements were achieved using the Harmonic Light Scattering technique to probe the role of the M[ONNO] chromophores and of the pi-complexation of the salicylidene ring in the nonlinearity. All the complexes exhibit a second-order nonlinear response increasing with the nuclearity, the hyperpolarizability (beta) value of the trinuclear complex 10 being 1.5 time larger than that of the metalloligand 8 (beta = 155 x 10(-30) esu). A rationalization of the structural, electronic, and redox properties of the title compounds is provided, based on a theoretical investigation at the density functional theory (DFT) level. Their UV-visible spectra has been assigned with the help of time-dependent (TD) DFT calculations. They are dominated by LMCT, MLCT, and pi-pi* transitions.

RESUMEN

The electronic communication between two redox centres through a Schiff base complex has been investigated in a series of ethylenediimine-bis(1-ferrocenyl-1,3-butanedionate) complexes of Zn(II) 1, Cu(II) 2, Ni(II) 3 and Co(II) 4. Cyclic voltammetry experiments of 1 and 2 exhibit a unique two-electron reversible oxidation wave, whereas in the case of 3 and 4 two and three one-electron oxidation processes are, respectively, observed. These results suggest some electronic interaction between the iron atoms of the ferrocenyl groups. DFT calculations carried out on model complexes show that for all the studied compounds the removal of the first two electrons corresponds to the oxidation processes of the iron centres in the weakly coupled ferrocenyl termini. The electronic communication between the two iron centres increases on going from 1 to 4. Finally, a re-indexation of the bands observed in the UV-Visible spectra has been carried out using TDDFT calculations.

RESUMEN

Representative members of a new family of covalently bonded charge-transfer molecular hybrids, of general formula [(eta5-C5H5)Fe(mu,eta6:eta1-p-RC6H4NN)Mo(eta2-S2CNEt2)3] +PF6- (R: H, 5+PF6-; Me, 6+PF6-; MeO, 7+PF6-) and [(eta5-C5Me5)Fe(mu,eta6:eta1-C6H5NN)Mo(eta2-S2CNEt2)3]+PF6-, 8+PF6-, have been synthesized by reaction of the corresponding mixed-sandwich organometallic hydrazines [(eta5-C5H5)Fe(eta6-p-RC6H4NHNH2)]+PF6- (R: H, 1+PF6-; Me, 2+PF6-; MeO, 3+PF6-) and [(eta5-C5Me5)Fe(eta6-C6H5NHNH2)]+PF6-, 4+PF6-, with cis-dioxomolybdenum(VI) bis(diethyldithiocarbamato) complex, [MoO2(S2CNEt2)2], in the presence of sodium diethyldithiocarbamato trihydrate, NaSC(=S)NEt2.3H2O, in refluxing methanol. These iron-molybdenum complexes consist of organometallic and inorganic fragments linked each other through a pi-conjugated aryldiazenido bridge coordinated in eta6 and eta1 modes, respectively. These complexes were fully characterized by FT-IR, UV-visible, and 1H NMR spectroscopies and, in the case of complex 7+PF6-, by single-crystal X-ray diffraction analysis. Likewise, the electrochemical and solvatochromic properties were studied by cyclic voltammetry and UV-visible spectroscopy, respectively. The electronic spectra of these hybrids show an absorption band in the 462-489 and 447-470 nm regions in CH2Cl2 and DMSO, respectively, indicating the existence of a charge-transfer transition from the inorganic donor to the organometallic acceptor fragments through the aryldiazenido spacer. A rationalization of the properties of 5+PF6--8+PF6- is provided through DFT calculations on a simplified model of 7+PF6-. Besides the heterodinuclear complexes 5+PF6--8+PF6-, the mononuclear molybdenum diazenido derivatives, [(eta1-p-RC6H4NN)Mo(eta2-S2CNEt2)3] (R: H, 9; Me, 10; MeO, 11), resulting from the decoordination of the [(eta5-C5H5)Fe]+ moiety of complexes 5+PF6--7+PF6-, were also isolated. For comparative studies, the crystalline and molecular structure of complex 10.Et2O was also determined by X-ray diffraction analysis and its electronic structure computed.