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1.
Front Psychol ; 15: 1325600, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38638523

RESUMO

Controlling the spread of COVID-19 requires individuals to adopt preventive behaviours, but conspiracy beliefs about its origin are spreading. The aim of this paper is to better comprehend the strength of conspiracy beliefs versus objective COVID-19 information to predict people's adherence to protective behaviours (getting vaccinated, being tracked through APPs, and keeping social distance from infected people). Study 1 shows that COVID-19 implicit theories detected in the Pre-study were activated as independent factors that constitute people's interpretations of the virus origin. These beliefs were related to a lesser intention to engage in preventive behaviours and a higher level of mistrust in institutional information, although some beliefs generate positive expectations about COVID-19 consequences. In Study 2, conducted with a different sample, official COVID-19 information was included as an independent variable, but this new variable did not further explain results. Lastly, Study 3 consisting of both previous samples confirmed that conspiracy beliefs had a direct effect on a lesser willingness to engage in preventive actions, a higher mistrust, and positive expectations about COVID-19 consequences. We conclude that objective COVID-19 information did not buffer the effect of conspiracy beliefs; they interfere with actions to prevent it by taking institutions as scapegoats or complicit with secret powers.

2.
Eur J Phys Rehabil Med ; 60(2): 373-381, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38502558

RESUMO

BACKGROUND: A high rate of hospitalized patients for COVID-19 had dysphagia, frequently underdiagnosed, and not treated, inducing a prolonged dysphagia with protracted recovery. Specific treatments and protocols have not been well described yet. AIM: Given the potential benefits of respiratory muscle training (IEMT) and neuromuscular stimulation (NMES) in dysphagia treatment, this study aimed to assess the feasibility of the protocol used for treating dysphagia in patients who experienced prolonged hospitalization for COVID-19. DESIGN: Observational, descriptive, prospective study. SETTING: Department of Physical Medicine and Rehabilitation of a tertiary University hospital. POPULATION: Fifty-eight COVID-19 patients were admitted for intensive rehabilitation (March 2020 to October 2021) were prospectively studied. METHODS: Dysphagia was diagnosed using videofluoroscopy and treated with a 3-week protocol adapted from neuromuscular stimulation (NMES) in a motor threshold and inspiratory/expiratory muscle strength training (IEMST), five sets of five repetitions three times daily for 3 weeks. Feasibility was assessed with adherence, outcomes achieved, and occurrence of adverse/unexpected events. Respiratory function (peak cough flow, maximal inspiratory/expiratory pressures) and swallow function (Penetration-Aspiration Scale and Bolus Residue Scale measured by videofluoroscopy) were recorded descriptive statistics, Student's t test for numerical data, and Wilcoxon Test for ordinal variables were applied. SPPSS vs28 and STATA version 15.1 (StataCorp, College Station, TX, USA) were used for statistical analysis. P values 0.05 were considered significant. RESULTS: Dysphagia was highly prevalent in severe COVID-19 patients (86.6%); all respiratory and swallow parameters improved after a 3-week intervention and 12 of 18 patients dependent on tube feeding resumed a normal diet (66.7%; McNemar P=0.03), and 84.09% attended a no restriction diet at discharge. Adherence to treatment was 85%. No significant adverse events were detected. CONCLUSIONS: We conclude that a structured swallowing-exercise training intervention based on IEMT and NMES is feasible and safe in prolonged hospitalization post-COVID patients. CLINICAL REHABILITATION IMPACT: To describe rehabilitation protocols used to treat dysphagia in post-COVID patients will help us to optimize the available techniques in each center and to induce a faster recovery avoiding potential complications.


Assuntos
COVID-19 , Transtornos de Deglutição , Acidente Vascular Cerebral , Humanos , Transtornos de Deglutição/etiologia , Transtornos de Deglutição/terapia , Resultado do Tratamento , Estudos Longitudinais , Estudos Prospectivos , Acidente Vascular Cerebral/complicações , COVID-19/complicações , Deglutição
3.
Artigo em Inglês | MEDLINE | ID: mdl-36981605

RESUMO

The main objective was to assess the feasibility of an intensive rehabilitation program (IRP) for stroke patients; and secondly, to detect eventual age-related differences in content, duration, tolerability, and safety in a prospective observational cohort of patients diagnosed with subacute stroke, admitted to inpatient rehabilitation (BRAIN-CONNECTS project). Activities during physical, occupational and speech therapy, and time dedicated to each one were recorded. Forty-five subjects (63.0 years, 77.8% men) were included. The mean time of therapy was 173.8 (SD 31.5) minutes per day. The only age-related differences when comparing patients ≥65 and <65 years were a shorter time allocated for occupational therapy (-7.5 min (95% CI -12.5 to -2.6), p = 0.004) and a greater need of speech therapy (90% vs. 44%) in the older adults. Gait training, movement patterns of upper limbs, and lingual praxis were the most commonly performed activities. Regarding tolerability and safety, there were no losses to follow-up, and the attendance ratio was above 95%. No adverse events occurred during any session in all patients. Conclusion: IRP is a feasible intervention in patients with subacute stroke, regardless of age, and there are no relevant differences on content or duration of therapy.


Assuntos
Terapia Ocupacional , Reabilitação do Acidente Vascular Cerebral , Acidente Vascular Cerebral , Masculino , Humanos , Idoso , Feminino , Reabilitação do Acidente Vascular Cerebral/métodos , Estudos de Viabilidade , Acidente Vascular Cerebral/terapia , Terapia Ocupacional/métodos , Extremidade Superior
4.
Foods ; 12(4)2023 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-36832924

RESUMO

Modified atmosphere packaging (MAP) has become a good potential strategy to retain quality throughout the shelf life of perishable foods. The aim of this work was to evaluate different packaging atmospheres on semi-hard protected designation of origin Idiazabal cheese wedges. Six different packaging treatments (air, vacuum, and CO2/N2 gas mixtures in the ratio of 20/80, 50/50, 80/20, and 100/0% v/v, respectively) were studied. Changes in gas headspace composition, cheese gross composition, weight loss, pH, acidity, colour, and textural and sensory properties were investigated during 56 days of refrigerated storage at 5 ± 1 °C. MAP was the most effective preserving technique compared to air- and vacuum-packaging treatments. The cheese characteristics with the greatest discriminating weight in the preservation techniques were paste appearance, holes, flavour, a* (redness) and b* (yellowness) colour parameters, and slope to hardness. Air-packaged cheeses, on 35 day, presented a mouldy flavour. Vacuum packaging affected paste appearance (greasy, plastic marks, and non-homogeneous colour) and holes (occluded and unnatural appearance) starting after 14 packaging days. MAP mixtures with CO2 concentration between 50/50 and 80/20% CO2/N2 (v/v) are recommended to ensure sensory quality and stability in the distribution of these raw sheep-milk cheese wedges.

5.
Eur Geriatr Med ; 13(6): 1365-1375, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36251169

RESUMO

PURPOSE: To analyse whether an intergenerational programme in which students interacted with institutionalised older persons had any impact on the older persons' functional status. METHODS: Each academic year, a group of older adults living in nursing homes were divided into two arms. For the next four months, the first group received daily visits from a group of students during which they followed a pre-established activity plan, whilst the other arm proceeded with their normal activity. After 4 months, the groups crossed over, and the second arm received the student visits, whilst the first group returned to their normal activity. A battery of tests was performed at inception, crossover and the end of the second period. The tests explored mobility (Timed Up-and-Go), cognition (Mini-Mental Examination), executive function (Frontal Assessment Battery) and mood (Geriatric Depression Scale). A dichotomous aggregate "significant impairment" variable was deemed to be present when there was at least a 20% loss of function (compared to the value at the beginning of the period) in any of the aforementioned tests. RESULTS: The study included 289 older adults who visited with 91 students. Subjects in the active phase had a lower incidence of significant impairment than those in the control phase (O.R. 0.90, p < 0.01). There were no significant differences in the individual variables. CONCLUSION: An intergenerational project with students visiting older adults in nursing homes had a protective effect, delaying functional decay in older adults.


Assuntos
Cognição , Casas de Saúde , Humanos , Idoso , Idoso de 80 Anos ou mais , Modalidades de Fisioterapia
6.
Artigo em Inglês | MEDLINE | ID: mdl-34574712

RESUMO

Cheese is a dairy product with potential health benefits. Cheese consumption has increased due to the significant diversity of varieties, versatility of product presentation, and changes in consumers' lifestyles. Spoilage of hard and semi-hard cheeses can be promoted by their maturation period and/or by their long shelf-life. Therefore, preservation studies play a fundamental role in maintaining and/or increasing their shelf-life, and are of significant importance for the dairy sector. The aim of this review is to discuss the most effective methods to ensure the safety and sensory quality of ripened cheeses. We review traditional methods, such as freezing, and modern and innovative technologies, such as high hydrostatic pressures, chemical and natural vegetable origin preservatives, vacuum and modified atmosphere packaging, edible coatings and films, and other technologies applied at the end of storage and marketing stages, including light pulses and irradiation. For each technology, the main advantages and limitations for industrial application in the dairy sector are discussed. Each type of cheese requires a specific preservation treatment and optimal application conditions to ensure cheese quality and safety during storage. The environmental impact of the preservation technologies and their contribution to the sustainability of the food chain are discussed.


Assuntos
Queijo , Atmosfera , Queijo/análise
8.
Inorg Chem ; 50(17): 8524-31, 2011 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-21834508

RESUMO

Rhenium(I) compounds [Re(CO)(3)(Hdmpz)(2)(ampy)]BAr'(4) and [Re(CO)(3)(N-MeIm)(2)(ampy)]BAr'(4) (Hdmpz = 3,5-dimethylpyrazole, N-MeIm = N-methylimidazole, ampy = 2-aminopyridine or 3-aminopyridine) have been prepared stepwise as the sole reaction products in good yields. The cationic complexes feature two different types of hydrogen bond donor ligands, and their anion binding behavior has been studied both in solution and in the solid state. Compounds with 2-ampy ligands are labile in the presence of nearly all of the anions tested. The X-ray structure of the complex [Re(CO)(3)(Hdmpz)(2)(ampy)](+) (2) shows that the 2-ampy ligand is metal-coordinated through the amino group, a fact that can be responsible for its labile character. The 3-ampy derivatives (coordinated through the pyridinic nitrogen atom) are stable toward the addition of several anions and are more selective anion hosts than their tris(pyrazole) or tris(imidazole) counterparts. This selectivity is higher for compound [Re(CO)(3)(N-MeIm)(2)(MeNA)]BAr'(4) (5·BAr'(4), MeNA = N-methylnicotinamide) that features an amido moiety, which is a better hydrogen bond donor than the amino group. Some of the receptor-anion adducts have been characterized in the solid state by X-ray diffraction, showing that both types of hydrogen bond donor ligands of the cationic receptor participate in the interaction with the anion hosts. DFT calculations suggest that coordination of the ampy ligands is more favorable through the amino group only for the cationic complex 2, as a consequence of the existence of a strong intramolecular hydrogen bond. In all other cases, the pyridinic coordination is clearly favored.


Assuntos
Monóxido de Carbono/química , Compostos Organometálicos/química , Rênio/química , Ânions/química , Cristalografia por Raios X , Ligação de Hidrogênio , Ligantes , Modelos Moleculares , Estrutura Molecular , Compostos Organometálicos/síntese química , Teoria Quântica , Estereoisomerismo
9.
Rev. latinoam. psicol ; 43(2): 279-288, mayo 2011. tab
Artigo em Espanhol | LILACS | ID: lil-637098

RESUMO

El objetivo de este trabajo es, por una parte, la adaptación al español de la Medida de la presencia social de las mentes en red (Networked Minds Social Presence Measure) de Harms & Biocca (2004) de 36 ítems, y en particular a entornos virtuales del aprendizaje, y por otra, la obtención de una versión reducida de la misma. Para ello se analizó la fiabilidad de la escala, se llevaron a cabo análisis factoriales de carácter exploratorio y confirmatorio y se estudió, además, la relación entre la presencia social y el aprendizaje percibido, a través de dos muestras transversales de estudiantes universitarios (n = 270 y 315, respectivamente). Los resultados muestran una buena fiabilidad del instrumento, replican la estructura factorial de la escala original y confirman una relación positiva de la presencia social con el aprendizaje percibido. La escala adaptada arroja una reducción a 17 ítems. Esto permite disponer de un instrumento más breve y adaptado a la medición de la presencia social en entornos virtuales de aprendizaje.


The aim of this paper is, on the one hand, to perform the Spanish adaptation of the Networked Minds Social Presence Measure (Harms & Biocca, 2004) with 36 items, and specifically, to virtual learning environments, and on the other hand, to obtain a shortened version of it. In doing so, the scale reliability was analyzed, exploratory and confirmatory factor analyzes were performed, and also the relationship between social presence and perceived learning was studied, by means of two cross-sectional samples of university students (n = 270 and 315, respectively). Results show good instrument reliability, reproduce the original scale factor structure, and confirm a positive relationship of social presence with perceived learning. The adapted scale was reduced to 17 items. This allows us to have a shorter instrument which is adapted to the measure of social presence in virtual learning environments.

10.
Chemistry ; 16(1): 227-32, 2010 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-19946914

RESUMO

A protocol for the rapid determination of the absolute configuration and enantiomeric excess (ee) of alpha-chiral primary amines with potential applications in asymmetric reaction discovery has been developed. The protocol requires derivatization of alpha-chiral primary amines through condensation with pyridine carboxaldehyde to quantitatively yield the corresponding imine. The Cu(I) complex with 2,2'-bis (diphenylphosphino)-1,1'-dinaphthyl (BINAP--Cu(I)) with the imine yields a metal-to-ligand charge-transfer (MLCT) band in the visible region of the circular dichroism (CD) spectrum upon binding. Diastereomeric host-guest complexes give CD signals of the same signs but different amplitudes, allowing for differentiation of enantiomers. Processing the primary optical data from the CD spectrum with linear discriminant analysis (LDA) allows for the determination of the absolute configuration and identification of the amines, and processing with a supervised multilayer perceptron artificial neural network (MLP-ANN) allows for the simultaneous determination of the ee and concentration. The primary optical data necessary to determine the ee of unknown samples is obtained in two minutes per sample. To demonstrate the utility of the protocol in asymmetric reaction discovery, the ee values and concentrations for an asymmetric metal-catalyzed reaction are determined. The potential of the application of this protocol in high-throughput screening (HTS) of ee is discussed.


Assuntos
Aminas/química , Metais/química , Catálise , Dicroísmo Circular , Ensaios de Triagem em Larga Escala , Ligantes , Estrutura Molecular , Estereoisomerismo
11.
Inorg Chem ; 48(24): 11963-75, 2009 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-19911828

RESUMO

The ortho functionalization of methyl R-phenylglycinate has been easily achieved using the known orthopalladated complex [Pd(mu-Cl){R-C(6)H(4)(CH(CO(2)Me)NH(2))-2}](2) (1) as synthetic tool. Different functional groups have been introduced at the ortho position of the aryl ring. The reaction of (R)-1 with X(2) or PhI(OAc)(2) gives XC(6)H(4)(CH(CO(2)Me)NH(2))-2 (X = I, Br, OMe, OEt) through oxidative coupling, while the reaction with CO gives an isoindolone. (R)-1 also reacts with one, two, or three alkyne molecules to give different metal-containing or metal-free heterocycles. The resulting functionalized amino esters or heterocycles retain the chirality of (R)-1, according with the values of the optical rotation and the obtained ee values ranging from 22%-87%. The X-ray structures of six representative compounds have also been determined.


Assuntos
Glicina/análogos & derivados , Compostos Organometálicos/química , Paládio/química , Carbono/química , Cristalografia por Raios X , Glicina/química , Halogênios/química , Modelos Moleculares , Conformação Molecular , Nitrogênio/química , Compostos Organometálicos/síntese química , Oxigênio/química , Estereoisomerismo
12.
Chem Commun (Camb) ; (22): 3279-81, 2009 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-19587939

RESUMO

The replacement of one pyrazole ligand by 2-aminopyridine in previously known rhenium tricarbonyl pyrazole complexes leads to more selective anion hosts.

13.
Rev. colomb. radiol ; 19(4): 2539-2541, dic. 2008.
Artigo em Espanhol | LILACS | ID: lil-529592

RESUMO

El artículo reporta el caso de un paciente de 57 años de edad, valorado en el servicio de imágenes diagnósticas del Hospital Militar Central (Bogotá, Colombia), quien presenta un cuadro inicial de pérdida de peso y masa en la clavícula derecha y cuyas radiografías muestran una lesión lítica en la porción esternal de la clavícula. La biopsia fue conclusiva para plasmocitoma, por lo que recibió radioterapia. Tres años después, el paciente presenta lesiones similares en la reja costal y afectación del testículo izquierdo. Se establece un diagnóstico de mieloma múltiple, por lo que se inicia quimioterapia y se le realiza una orquiectomía izquierda. Un año más tarde, el paciente presenta dolor abdominal difuso e inespecífico, por lo que se realizan diversos estudios, incluidos US y TC abdominal con contraste, los cuales detectan una masa heterogénea e irregular que afecta el retroperitoneo en sus tres espacios. La biopsia de la masa reportó proliferación de plasmocitos pleomórficos con núcleos hipercrómicos, compatible con mieloma múltiple.


Assuntos
Humanos , Mieloma Múltiplo , Espaço Retroperitoneal , Tomografia , Tomografia Computadorizada por Raios X
14.
Org Lett ; 10(22): 5167-70, 2008 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-18939802

RESUMO

Racemic-metal complexes were used to determine identity, enantiomeric excess, and concentration of chiral diamines using metal-to-ligand charge transfer bands in circular dichroism spectroscopy. It takes under just 2 min per sample to determine [G]t and %R with tolerable errors (19% and 4%, respectively). The simplicity of the achiral receptors employed confers to this technique great potential for high-throughput screening.


Assuntos
Compostos Organometálicos/química , Dicroísmo Circular , Diaminas/análise , Modelos Lineares , Estereoisomerismo , Fatores de Tempo
15.
J Am Chem Soc ; 130(29): 9232-3, 2008 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-18572934

RESUMO

This manuscript describes a protocol for the fast determination of identity, enantiomeric excess (ee) and concentration of chiral 1,2-diamines, the combination of which has not previously been achieved, using the changes in the circular dichroism (CD) spectra of the charge-transfer bands of the Cu(I)-Binap complex. The spectra were analyzed with a variety of pattern recognition (PR) protocols. PR techniques were used to analyze unknown samples in a robotically controlled 96-well plate interfaced CD instrument. In less than two minutes per sample, ee and concentration values can be read with 2% and 8% error, respectively. The speed and accuracy as well as ability to simultaneously measure ee concentration and identity represent clear advantages over traditional methods and makes this method adaptable to true high-throughput screening.


Assuntos
Dicroísmo Circular/métodos , Técnicas de Química Combinatória/métodos , Cobre/química , Compostos Organometálicos/química , Diaminas/química , Ligantes , Naftalenos/química , Redes Neurais de Computação , Estereoisomerismo
16.
Inorg Chem ; 46(8): 3407-18, 2007 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-17367132

RESUMO

Compound cis,fac-[Mo(eta3-allyl)(CO)2(Hdmpz)3]BAr'4 (1) (Hdmpz = 3,5-dimethylpyrazole, Ar' = 3,5-bis(trifluoromethyl)phenyl) undergoes rapid substitution of one of the pyrazole ligands by anions, including the low nucleophilic ReO4-, a reaction that afforded [Mo(OReO3)(eta3-allyl)(CO)2(Hdmpz)2] (2), structurally characterized by X-ray diffraction. The new compounds fac-[Mn(CO)3(Hdmpz)3]BAr'4 (4a) and fac-[Mn(CO)3(HtBupz)3]BAr'4 (4b) (HtBupz = 3(5)-tert-butylpyrazole) also undergo pyrazole substitution with most anions, and the product from the reaction with nitrate was crystallographically characterized. Compounds 4a,b were found to be substitutionally stable toward perrhenate, and the adducts [Mn(CO)3(Hdmpz)3].[ReO4] (7a) and [Mn(CO)3(HtBupz)3].[ReO4].[Bu4N].[BAr'4] (7b), crystallographically characterized, display hydrogen bonds between one of the perrhenate oxygens and the N-H groups of two of the pyrazole ligands. The structurally similar adduct [Re(CO)3(Hdmpz)3].[ReO4] (8) was found to result from the interaction of [Re(CO)3(Hdmpz)3]BAr'4 with perrhenate. The reaction of [Re(OTf)(CO)5] with 3,5-dimethylpyrazole (Hdmpz) afforded [Re(CO)5(Hdmpz)]OTf (9). The reaction of 9 with Hdmpz and NaBAr'4 yielded [Re(CO)4(Hdmpz)2]BAr'4 (10), which was found to be unstable toward chloride anion. In contrast, the new compound fac,cis-[Re(CO)3(CNtBu)(Hdmpz)2]BAr'4 (11) is stable in solution in the presence of different anions. Binding constants for 11 with chloride, bromide, and nitrate are 1-2 orders of magnitude lower than those found for these anions and rhenium tris(pyrazole) hosts, indicating that the presence of the third pyrazole ligand is crucial. Compounds fac-[Re(CO)3(HPhpz)3]BAr'4 (14) (HPhpz = 3(5)-phenylpyrazole) and fac-[Re(CO)3(HIndz)3]BAr'4 (15) (HIndz = indazole) are, in terms of anion binding strength and selectivity, inferior to those with dimethylpyrazole or tert-butylpyrazole ligands.


Assuntos
Metais Pesados/química , Compostos Organometálicos/química , Pirazóis/química , Ânions/química , Cristalografia por Raios X , Ligantes , Modelos Moleculares , Estrutura Molecular , Compostos Organometálicos/síntese química , Estereoisomerismo
17.
Inorg Chem ; 46(7): 2846-53, 2007 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-17302409

RESUMO

Compounds [Mo(CO)4(N-N)] (N-N = 4,4'-bis((4-methylphenyl)carbamoyl)-2,2'-bipyridine, bipy', 1; or 2,2'-biimidazole, H2biim, 2), [MoCl(eta3-methallyl)(CO)2(N-N)] (N-N = bipy', 3; H2biim, 4), and [Mo(eta3-methallyl)(CNtBu)(CO2)(N-N)]BAr'4 (Ar' = 3,5-bis(trifluoromethyl)phenyl; N-N= bipy', 5; H2biim, 6) were synthesized and characterized, and their behavior toward anions was investigated in solution (IR and 1H NMR) and in solid state (X-ray diffraction).


Assuntos
Amidas/química , Imidazóis/química , Molibdênio/química , Piridinas/química , Ânions/química , Cristalografia por Raios X , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Estrutura Molecular
18.
Inorg Chem ; 45(17): 7018-26, 2006 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-16903762

RESUMO

The reaction of fac-[ReBr(CO)3(NCMe)2] (1) with either pyrazole (Hpz) or 3,5-dimethylpyrazole (Hdmpz) in a 1:2 Re/pyrazole ratio affords the known complexes fac-[ReBr(CO)3(Hpz)2] (2) and [ReBr(CO)3(Hdmpz)2] (3). Using a 1:1 ratio, MeCN as solvent, and longer reaction times led to a mixture in which the major components are the pyrazolylamidino complexes fac-[ReBr(CO)3(HN=C(CH3)pz-kappa2N,N)] (4) and fac-[ReBr(CO)3(HN=C(CH3)dmpz-kappa2N,N)] (5). The complexes fac-[ReBr(CO)3(Hpz)(NCMe)] (6) and fac-[ReBr(CO)3(Hdmpz)(NCMe)] (7) (along with 2 and 3) were found to be minor components of these reactions. Analogous reactions of fac-[Re(OClO3)(CO)3(NCMe)2] yielded fac-[Re(NCCH3)(CO)3(HN=C(CH3)pz-kappa2N,N)]ClO4 (8), fac-[Re(NCCH3)(CO)3(HN=C(CH3)dmpz-kappa2N,N)]ClO4 (9), fac-[Re(Hpz)(CO)3(HN=C(CH3)pz-kappa2N,N)]ClO4 (10), and fac-[Re(Hdmpz)(CO)3(HN=C(CH3)dmpz-kappa2N,N)]ClO4 (11). The X-ray structure of 11 showed the perchlorate anion to be hydrogen-bonded by the N-H groups of the pyrazole and pyrazolylamidino ligands. The behavior of the compound fac-[Re(Hdmpz)(CO)3(HN=C(CH3)dmpz-kappa2N,N)]BAr'4 (13) (synthesized by reaction of [ReBr(CO)3(Hdmpz)2] (3) with (i) AgOTf and (ii) NaBAr'(4)/MeCN) as an anion receptor has been studied in CD3CN solution. In addition, the structure of the supramolecular adduct fac-[Re(CO)3(Hdmpz)(HN=C(CH3)dmpz-kappa2N,N)].Cl (14), featuring chloride binding by the two N-H groups, was determined by X-ray diffraction.

19.
Chemistry ; 12(8): 2244-51, 2006 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-16370004

RESUMO

The behavior of the receptors [Re(CO)3(Hdmpz)3]BAr'4 (Hdmpz = 3,5-dimethylpyrazole) (1) and [Re(CO)3(HtBupz)3]BAr'4 (HtBupz = 3(5)-tert-butylpyrazole) (2; Ar' = 3,5-bis(trifluoromethyl)phenyl) toward the anions fluoride, chloride, bromide, iodide, hydrogensulfate, dihydrogenphosphate, nitrate, and perrhenate was studied in CD3CN solution. In most cases, the receptors were stable. Anion exchange was fast, and binding constants were calculated from the NMR titration profiles. The structure of the adduct [Re(CO)3(HtBupz)3] x NO3 (3) was determined by X-ray diffraction. Two pyrazole moieties are hydrogen-bonded to one nitrate oxygen atom, and the third pyrazole moiety is hydrogen-bonded to an oxygen atom of an adjacent nitrate, leading to infinite chains. The structure of the adduct [Re(CO)3(Hdmpz)3]BAr'4acetone (4), also determined by X-ray diffraction, showed a similar interaction of two pyrazole N-H groups with the acetone oxygen atom. F- and H2PO4(-) deprotonate the receptors, and HSO4(-) decomposed 1. The structure of one of the decomposition products (5), determined by X-ray diffraction, is consistent with pyrazole protonation and substitution by sulfate.

20.
Dalton Trans ; (5): 884-8, 2005 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-15726140

RESUMO

Cationic complexes [Mo(eta(3)-allyl)(CO)2L3]+ (L3 = either nitrogen-donor tridentate ligand or three monodentate ligands) were prepared in high yield and under mild conditions using as precursors either the triflato complex [Mo(eta(3)-allyl)(OTf)(CO)2(NCMe)2] or the combination of the chloro complex [Mo(eta(3)-allyl)Cl(CO)2(NCMe)2] and the salt NaBAr'(4)(Ar'= 3,5-bis(trifluoromethyl)phenyl). The tridentate ligands employed were 2,2':6',2'-terpyridine (terpy) and cis,cis-1,3,5-cyclohexanetriamine (CHTA), whereas the monodentate ligands imidazole (im) and 3,5-dimethylpyrazole (dmpz) were chosen. In order to stabilize the labile intermediates, an excess of acetonitrile was used in most of the syntheses. However, the pyrazole complex was prepared through a nitrile-free route to avoid reactions at the coordinated nitrile. The solid state structures of [Mo(eta(3)-methallyl)(CO)2(terpy)]OTf (2), [Mo(eta(3)-methallyl)(CO)2(CHTA)]BAr'4 (3), [Mo(eta(3)-methallyl)(CO)2(NCMe)3]BAr'4 (4), [Mo(eta(3)-allyl)(CO)2(im)3]OTf (5) and [Mo(eta(3)-allyl)(CO)2(dmpz)3]BAr'4 (6) were determined by means of single-crystal X-ray diffraction.


Assuntos
Molibdênio/química , Nitrogênio/química , Compostos Organometálicos/química , Cristalografia por Raios X , Ligantes , Molibdênio/metabolismo , Nitrogênio/metabolismo
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