27 research outputs found

    Co-crystal of suberic acid and 1,2-bis(4-pyridyl)ethane: A new case of packing polymorphism

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    The polymorphic behaviour of a co-crystal composed of neutral suberic acid and 1, 2-bis(4-pyridyl)ethane is reported. A multidisciplinary approach has been employed, using thermal analysis methods (differential scanning calorimetry and polarized light thermomicroscopy), spectroscopic methods (infrared spectroscopy) and X-ray single crystal and powder diffraction. Two new polymorphs, I and III; have been identified, and for one of them the crystal structure has been elucidated and compared to that of a known polymorph, form II, showing that the assembling of the molecules in chains via H-bonds is a common feature of both polymorphs. Polymorph II, obtained by crystallization from an aqueous or ethanol solution or by grinding, undergoes a solid-solid transition to polymorph I, which melts at 180.5 °C. Upon cooling from the melt, polymorph I is obtained, and a solid-solid transformation also occurs, to polymorph III''. Polymorph III was obtained serendipitously in an attempt to prepare a Nd(III) complex. The relative stability of the three polymorphic forms was established

    The Mossbauer effect using Fe-57-ferrabisdicarbollide ([o-(57)FESAN](-)): a glance into the potential of a low-dose approach for glioblastoma radiotherapy

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    Although a variety of cancers are initially susceptible to chemotherapy, they eventually develop multi-drug resistance. To overcome this situation, more effective and selective treatments are necessary using anti-tumour agents that act in two or more ways and offer greater therapeutic benefits over single-mechanism entities. In this study, we report on treating cancer with Na[3,3′-57Fe(1,2-C2B9H11)2], which offers the possibility of dual action (radiation-drug combinations) to improve the clinical benefits and reduce healthy tissue toxicity. An approach to evaluating the potential of [o-57FESAN]− to treat glioblastoma using the Mössbauer effect is presented. As the therapeutic outcomes rely on the amount and distribution of [o-57FESAN]− inside the cells, several studies, using magnetization, Mössbauer spectroscopy and nuclear microscopy techniques, were performed to ascertain the uptake of [o-57FESAN]− in U87 glioblastoma cells. [o-57FESAN]− was found to be within the cells; 29% of its uptake was in the nuclear fraction, which is a particularly desirable target, because the nucleus is the cell's control centre where DNA and the transcription machinery reside. Irradiation studies with 2D and 3D cellular models of U87 cells showed that the growth inhibition effect observed was more pronounced when [o-57FESAN]− was used in combination with the Mössbauer effect in low total dose regimens, suggesting that this procedure either alone or as adjuvant may be useful for glioblastoma treatment.This work was supported by the Spanish Ministerio de Economía y Competitividad (PID2019-106832RB-100) and the Generalitat de Catalunya (2017SGR1720) and by the Fundação para a Ciência e Tecnologia (FCT/MEC) for projects UID/MULTI/04349/2020, PTDC/BTM-TEC/29256/2017, UIDB/04565/2020, UIDP/04565/2020 (iBB/IST), LA/P/0140/2020 (Associate Laboratory Institute for Health and Bioeconomy – i4HB), PTDC/QUI-QIN/32240/2017, LISBOA-01-0145-FEDER-022096 (National Infrastructure Roadmap, LTHMFL-NECL) and GCT grant to A. C. Cerdeira (BL156/2019_IST-ID). A. B. Buades was enrolled in the PhD program of the UAB. C. I. G. Pinto is enrolled in the PhD scholarship 689 DFA/BD/07119/2020. The authors thank Dr Moulay Sougrati, Charles Gerhardt Institute, ICGM UMR 5253, Montpellier, France for a kind gift of 57FeCl2. The LMRI (Metrology Laboratory of Ionizing Radiation) team is acknowledged for their support in the X-ray irradiation setup.With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).Peer reviewe

    On the influence of transuranium dilution in well-known U heavy-fermion compounds

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    Synthesis and preliminary studies on U1−xNpxPd2Al3 and U1−xNpxRu2Si2 are presented. In all Np compounds measured here, no superconducting transition was found down to 1.4 K. In U1−xNpxPd2Al3 a small amount (0.01 less-than-or-equals, slant x less-than-or-equals, slant 0.05) of Np induces an anomaly in the lattice parameters and presents in resistivity measurements a sharp minimum at low temperature

    CCDC 1544884: Experimental Crystal Structure Determination

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    Related Article: Maria A. Susano, Pablo Martín-Ramos, Teresa M.R. Maria, Steven Folkersma, Laura C.J. Pereira, Manuela Ramos Silva|2017|J.Mol.Struct.|1147|76|doi:10.1016/j.molstruc.2017.06.043,An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

    Magnetic anisotropy of U2Pd2In

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    Magnetic susceptibility studies of the U2Pd2In single crystal show that in the paramagnetic state larger χ-values are found for field along the basal plane than along the c-axis. However, below TN = 37 K, where U-moments form a non-collinear magnetic structure within the basal plane, a cross-over of the two χ-branches occurs. The single crystal results may explain the origin of the exotic magnetization results obtained on powder samples

    Hybridization effects in U2T2X compounds: Magnetic structures of U2Rh2Sn and U2Ni2In

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    The tetragonal intermetallic compounds U2Ni2In and U2Rh2Sn have been studied by means of specific-heat, electrical-resistivity, and neutron-diffraction techniques. At low temperatures, both compounds order antiferromagnetically in a magnetic unit cell doubled along the c axis, and we find 5f moments of 0.60 and 0.38 Bohr magneton/U atom for U2Ni2In and U2Rh2Sn, respectively. For U2Ni2In, our refinement also indicates a possible Ni moment of 0.37 Bohr magneton perpendicular to the U moments. We discuss the development of the 5f moments together with findings on other isostructural U2T2X (T=transition metal, X=In, Sn) compounds, and confirm that the trends expected due to 5f-ligand hybridization also hold for this family of uranium compounds. Our analysis indicates different arrangements of the 5f moments in the two compounds (noncollinear arrangement within the basal plane for U2Ni2In and collinear arrangement along the c axis for U2Rh2Sn), although both compounds have nearest-neighbor U-U distances along the c axis. This would mean that the magnetocrystalline anisotropy in U2T2X compounds is not determined by nearest-neighbor U-U links alon
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