Publications by authors named "Maria Vanda Marinho"

A three-dimensional terbium(III) coordination polymer of formula [Tb(bttb)(2,5-pzdc)] (1) [Hbttb = 1,2,4,5-tetrakis(4'-carboxyphenyl)benzene and H-2,5-pzdc = 2,5-pyrazinedicarboxylic acid] was obtained under hydrothermal conditions. The bttb tetraanion in 1 adopts the bridging and chelating-bridging pseudo-oxo coordination modes while the 2,5-pzdc dianion exhibits a rather unusual bis-bidentate bridging pseudo-oxo coordination mode, both ligands being responsible for the stiffness of the resulting 3D structure. Solid-state photoluminescent measurements illustrate that 1 exhibits remarkable green luminescence emission, the most intense band occurring in the region of 550 nm (D → F) with lifetimes at the millisecond scale.

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Herein, we describe the synthesis, crystal structure, and electronic properties of {[K(dmso)(HO)][Ni(Hmpba)]·dmso·2HO} () and [Ni(HO)][Ni(Hmpba)]·3CHOH·4HO () [dmso = dimethyl sulfoxide; CHOH = methanol; and Hmpba = 1,3-phenylenebis(oxamic acid)] bearing the [Ni(Hmpba)] helicate, hereafter referred to as {Ni}. SHAPE software calculations indicate that the coordination geometry of all the Ni atoms in 1 and 2 is a distorted octahedron (O) whereas the coordination environments for K1 and K2 atoms in 1 are Snub disphenoid J84 (D) and distorted octahedron (O), respectively. The {Ni} helicate in is connected by K counter cations yielding a 2D coordination network with topology.

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In this work, we present the synthetic pathway, a refined structural description, complete solid-state characterization and the magnetic properties of four new cobalt(ii) compounds of formulas [Co(HO)][Co(Hmpba)]·2HO·0.5dmso (1), [Co(HO)][Co(Hmpba)]·3HO·0.5dpss (2), [Co(Hmpba)(HO)]·4nHO (3), and [Co(Hmpba)(CHOH)(HO)]·0.

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We herein present the synthesis, spectroscopic analysis, description of the crystal structures and magnetic properties of four new complexes of the formula [{Cu(opba)(HO)}{Cu(dmphen)(SCN)}]·dmf (1), [{Cu(opba)}{Cu(dmphen)Cl}]·1.5dmf·2.5dmso (2), [{Cu(opba)}{Cu(dmphen)Br}]·dmf·2.

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In the series described in this work, the hydrothermal synthesis led to oxidation of the 5-methyl-pyrazinecarboxylate anion to the 2,5-pyrazinedicarboxylate dianion (2,5-pzdc) allowing the preparation of three-dimensional (3D) lanthanide(III) organic frameworks of formula {[Ln(2,5-pzdc)(HO)]·6HO} [Ln = Ce (1), Pr (2), Nd (3), and Eu (4)] and {[Er(2,5-pzdc)(HO)]·5HO} (5). Single-crystal X-ray diffraction on 1-5 reveals that they crystallize in the triclinic system, P1̅ space group with the series 1-4 being isostructural. The crystal structure of the five compounds are 3D with the lanthanide(III) ions linked through 2,5-pzdc dianions acting as two- and fourfold connectors, building a binodal 4,4-connected (4·68)(468)-mog network.

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From the reaction between a dinuclear paddle-wheel carboxylate, namely [Cu2mu-(O2CCH2C4H3S)4] (1), and the flexible ligand 1,3-bis(4-pyridyl)propane (BPP) a neutral 2-D coordination polymer [[Cu2(O2CCH2C4H3S)4mu-(BPP)2]]n (2) was obtained. Compounds 1 and 2 were characterized by means of elemental analysis, thermal analysis (TG/DSC), vibrational spectroscopy, and electron paramagnetic resonance (EPR). The crystal structure of 2 reveals that each Cu(II) is coordinated by two nitrogen atoms from different BPP ligands and two 3-thiopheneacetate groups within a distorted square planar geometry in a trans-[N, N, O, O] arrangement.

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