Publications by authors named "Marcos A Ribeiro"

We report a synthetic strategy that allows for the preparation of sterically encumbered heteroleptic Ru(II)porphyrinates with the desired configuration of stable/inert and weak/labile axial ligands to direct reactions between substrates to exclusively occur at the sterically encumbered face. To demonstrate the method, we describe the synthesis of a strapped-Ru(II)porphyrinate bearing a stable/inert triphenylphosphine (PPh) bulky axial ligand coordinated to the central cavity and a weak/labile methanol molecule coordinated at the internal axial position. With this axial ligand configuration, the reported Ru(II)porphyrinate exclusively promotes carbene transfer reactions to olefins through the central cavity, which has been verified by the selective formation of cycloprane-linked [2]rotaxanes.

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To further explore the structural features and potential antibacterial and antitumor activities of polynuclear Cu coordination compounds with nalidixic acid (nx) derivatives, new complexes bearing nx hydrazones with N-pyridinyl moieties substituted at positions 2 and 3 (h2py and h3py) were synthesized. Complexes [Cu(CHNO)(CHNO)(HO)]4BF∙HO (1), and [Cu(CHNO)(CHNO)(HO)]4BF∙3HO (%) (2) were synthesized using h2py and h3py with Cu(BF)∙nHO as precursor, whereas the [Cu(CHNO)Cl]∙0.5HO complex (3) was synthesized with h2py and CuCl∙2HO.

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A simple and fast methodology under microwave irradiation for the synthesis of 2-aminopyrimidine and pyrazole derivatives using Atwal reaction is reported. After the optimization of the reaction conditions, eight 2-aminolpyrimidines containing ferrocene and heterocycles and three ferrocene pyrazoles were synthesized from the respective chalcones in good yields. Eight compounds had their structure determined by X-ray diffraction.

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Selectivity in N-H and S-H carbene insertion reactions promoted by Ru(II)porphyrinates currently requires slow addition of the diazo precursor and large excess of the primary amine and thiol substrates in the reaction medium. Such conditions are necessary to avoid the undesirable carbene coupling and/or multiple carbene insertions. Here, the authors demonstrate that the synergy between the steric shielding provided by a Ru(II)porphyrinate-based macrocycle with a relatively small central cavity and the kinetic stabilization of otherwise labile coordinative bonds, warranted by formation of the mechanical bond, enables single carbene insertions to occur with quantitative efficiency and perfect selectivity even in the presence of a large excess of the diazo precursor and stoichiometric amounts of the primary amine and thiol substrates.

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A 5,15-bis(1,1'-biphenyl)porphyrin-based molecular clip covalently connected to a ditopic aliphatic ester loop moiety yields a semi-rigid macrocycle with a well-defined cavity. The resulting macrocycle fits the structural requirements for the preparation of porphyrinates capable of promoting formation of C-C bonds. To demonstrate the usefulness of porphyrin-based macrocycles, an active-metal-template synthesis of rotaxanes through a redox non-innocent carbene transfer reaction is described.

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The paper reflected on the Brazilian Nursing education from the regulation of Unified Health System in a comparative historical perspective of the evolutionary processes of the Anglo-American and French schools, influencing Brazilian nursing education, as well as the guiding aspect of nursing education for the Unified Health System. Thus, nursing training initiatives guided by the National Curriculum Guidelines are developed to provide meaningful experiences in the Unified Health System's daily routine, as well as the transforming movement of Permanent Health Education in the context of the world of work. Therefore, overcoming training challenges must consider the social, political, and cultural path of the profession in order to allow changes that affect pedagogical projects, course offerings, teaching-learning methodologies, and daily work.

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A Co /porphyrinate-based macrocycle in the presence of a 3,5-diphenylpyridine axial ligand functions as an endotopic ligand to direct the assembly of [2]rotaxanes from diazo and styrene half-threads, by radical-carbene-transfer reactions, in excellent 95 % yield. The method reported herein applies the active-metal-template strategy to include radical-type activation of ligands by the metal-template ion during the organometallic process which ultimately yields the mechanical bond. A careful quantitative analysis of the product distribution afforded from the rotaxane self-assembly reaction shows that the Co /porphyrinate subunit is still active after formation of the mechanical bond and, upon coordination of an additional diazo half-thread derivative, promotes a novel intercomponent C-H insertion reaction to yield a new rotaxane-like species.

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3-nitropropionic acid (3-NPA) is a nitrogenated compound produced by plants and fungi and has been associated with poisoning episodes in humans, animals, and to induction of Huntington disease symptoms in rats. The production of 3-NPA by endophytes has been reported, but the function and biosynthesis are not well-defined. The specie of endophytic strain G-01 was confirmed as Diaporthe citri using a multilocus sequence analysis, and was verified different concentrations of 3-NPA produced at different initial pHs by these strain.

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Chemical investigation of the tubers of Sinningia allagophylla led to the isolation of two new chromenes, (2S)-12-hydroxylapachenole (1) and (3R)-3,4-dihydro-3-hydroxy-4-oxo-8-methoxylapachenole (2), and three new dimeric chromenes, allagophylldimers A-C (3-5). Thirteen known compounds, 6-methoxy-7,8-benzocoumarin (6), lapachenole, 8-methoxylapachenole, tectoquinone, 7-hydroxytectoquinone, dunniol, α-dunnione, dunnione, 8-hydroxydunnione, aggregatin E, cedrol, oleanolic acid, and halleridone, were also identified. 6-Methoxy-7,8-benzocoumarin (6) has been isolated for the first time from a natural source.

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A novel series of copper(II) coordination polymers [Cu2(O2CC8H9)4(pyz)]n (1), [Cu2(O2CC8H9)4(dps)]n (2), {[Cu(O2CC8H9)2(dps)(H2O)]·H2O}n (3), {[NaCu(O2CC8H9)2(bpm)(NO3)]·H2O}n (4), and [Cu4(O2CC8H9)6(OH)2(bpp)2]n (5) [O2CC8H9− = 3-phenylpropionate anion, pyz = pyrazine, dps = di(4-pyridyl)sulfide, bpm = 2,2′-bipyrimidine, and bpp = 1,3-bis(4-pyridyl)propane] have been synthesized and magneto-structurally investigated. Compounds 1 and 2 belong to a large group of copper(II) carboxylates where bis-monodentate pyz (1) and dps (2) ligands connect the paddle-wheel [CuII2(μ-O2CC8H9)4] units leading to alternating copper(II) chains. The structure of 3 consists of uniform chains of trans-[CuII(O2CC8H9)2] units linked by the bis-monodentate dps ligand.

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Synthetic strategies that comply with the principles of green chemistry represent a challenge: they will enable chemists to conduct reactions that maximize the yield of products with commercial interest while minimizing by-products formation. The search for catalysts that promote the selective oxidation of organic compounds under mild and environmentally friendly conditions constitutes one of the most important quests of organic chemistry. In this context, metalloporphyrins and analogues are excellent catalysts for oxidative transformations under mild conditions.

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Human adipose-derived stem cells (hASCs) are an attractive cell source for therapeutic applicability in diverse fields for the repair and regeneration of damaged or malfunctioning tissues and organs. There is a growing number of cell therapies using stem cells due to their characteristics of modulation of immune system and reduction of acute rejection. So a challenge in stem cells therapy is the delivery of cells to the organ of interest, a specific site.

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Purpose: A four-group randomized controlled trial evaluated the impact of distinct workplace interventions to increase the physical activity (PA) and to reduce anthropometric parameters in middle-age women.

Methods: One-hundred and ninety-five women age 40-50 yr who were employees from a university hospital and physically inactive at their leisure time were randomly assigned to one of four groups: minimal treatment comparator (MTC; n = 47), pedometer-based individual counseling (PedIC; n = 53), pedometer-based group counseling (PedGC; n = 48), and aerobic training (AT; n = 47). The outcomes were total number of steps (primary outcome), those performed at moderate intensity (≥ 110 steps per minute), and weight and waist circumference (secondary outcomes).

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A unique bistable copper-metallacyclic complex is used as an elegant molecular switch for the reversible formation of emulsions by simple pH variation. This switch may have several exciting applications in biphasic processes such as catalysis and separation science technologies.

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A new compound of formula (Bu4N)2[Mn2{Cu(opba)}2ox] (1) [Bu4N(+) = tetra-n-butylammonium cation, H4opba = 1,2-phenylenebis(oxamic acid), and H2ox = oxalic acid] has been synthesized and magneto-structurally investigated. The reaction of manganese(II) acetate, [Cu(opba)](2-), and ox(2-) in dimethyl sulfoxide yielded single crystals of 1. The structure of 1 consists of heterobimetallic oxamato-bridged Cu(II)Mn(II) chains which are connected through bis-bidentate oxalate coordinated to the manganese(II) ions to afford anionic heterobimetallic layers of 6(3)-hcb net topology.

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For the new organic salt 1H-imidazol-3-ium 1,4-dioxo-1,4-dihydronaphthalen-2-olate, C3H5N2(+)·C10H5O3(-), ab initio calculations of the gas-phase structures of the lawsonate and imidazolium ions were performed to help in the interpretation of the structural features observed. Three different types of hydrogen bond are responsible for the three-dimensional packing of the salt.

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We herein present the synthesis and X-ray structures of five copper(II) complexes of formulae [Cu(bpca)(CF3SO3)(H2O)]·H2O (1), [Cu(bpca)(Phpr)(H2O)]·3/2H2O (2), {[Cu(bpca)]2[Cu(opba)(H2O)]}·H2O (3), {[Cu(bpca)]2(H2opba)}2·6H2O (4) and [Cu(bpca)(EtH2opba)]n (5), where bpca = bis(2-pyridylcarbonyl)amidate, Phpr = 3-phenylpropionate, CF3SO3(−) = triflate (anion of the trifluoromethanesulphonic acid), H4opba = N,N′-1,2-phenylenebis(oxamic acid), and EtH3opba = monoethyl ester derivative of the H4opba. 1 and 2 are mononuclear copper(II) complexes where the copper atom is five-coordinate in distorted square pyramidal surroundings with a tridentate bpca and a water molecule (1)/carboxylate oxygen (2) building the basal plane and a triflate oxygen (1)/water molecule (2) filling the apical position. 3 is a neutral tricopper(II) complex where the [Cu(opba)(H2O)]2− unit acts as a bis-bidentate ligand toward two peripheral [Cu(bpca)]+ fragments.

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Bi-stable molecular systems presenting valence tautomerism are associated with the development of new functional materials, which can be used for applications in organic electric conductors, optoelectronic and molecular magnetic devices. The properties of these materials can be adjusted with slight chemical changes and can be induced by external stimuli. Typical examples of valence tautomer compounds are coordination complexes of Co and o-dioxolene ligands, notably quinone like ones.

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The methanol crude extract of the leaves of Ficus radicans Roxb. 'Variegata' (Moraceae) and the n-hexane, ethyl acetate and aqueous methanol fractions resulting from its fractionation were evaluated for their anti-inflammatory, molluscicidal and free-radical scavenging activities. The crude extract and fractions exhibited significant inhibition of inflammation in both croton oil (CO)-induced ear oedema in mice (p<0.

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The regular practice of physical activity at appropriate levels ensures various benefits for the individual over the short, medium and long terms. It is therefore important in health promotion. On the other hand, sedentary behavior has reached alarming levels among the general population, which qualifies it as a serious health problem of endemic proportions.

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Objective: Memory is composed of several systems and processes, and recognition can be accompanied by two subjective states of consciousness: autonoetic awareness, which characterizes conscious recollection; and noetic (or semantic) awareness, related to feelings of familiarity. The objective of this study was to describe the adaptation to Portuguese of an experiential procedure for investigation of states of awareness that accompany recognition.

Methods: Development of the material (word list and instructions permitting manipulation of the level of information processing); translation/adaptation of the original instructions to Portuguese; and application of the procedure in healthy volunteers and patients with schizophrenia.

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