200 research outputs found

    Copper(II)–Thymine Coordination Polymer Nanoribbons as Potential Oligonucleotide Nanocarriers

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    This is the peer reviewed version of the following article: Vegas, V. G., Lorca, R., Latorre, A., Hassanein, K., Gómez‐García, C. J., Castillo, O., ... & Amo‐Ochoa, P. (2017). Copper (II)–Thymine Coordination Polymer Nanoribbons as Potential Oligonucleotide Nanocarriers. Angewandte Chemie International Edition, 56(4), 987-991, which has been published in final form at https://doi.org/10.1002/anie.201609031. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived VersionsThe direct reaction between copper nitrate, thymine-1-acetic acid, and 4,4′-bipyridine in water leads to the formation of a blue colloid comprising uniform crystalline nanoribbons (length >1 μm; width ca. 150–185 nm; diameter ca. 15–60 nm) of a coordination polymer. The polymer displays a thymine-based structure freely available for supramolecular interactions. These nanostructures show significant selective interaction with single-stranded oligonucleotides based on adenine. Remarkably, they present low cell toxicity in three cell lines–despite the copper(II) content–and can be used as nanocarriers of oligonucleotides. These results suggest the potential of these types of nanostructures in several biological applicationsFinancial support from the Spanish Ministerio de Economía y Competitividad (MAT2016‐75883‐C2‐2‐P, MAT2016‐77608‐C3‐1‐P, MAT2013‐46502‐C2‐1P/2P, MAT2013‐46753‐C2‐1‐P, MAT2010‐20843‐C02‐01, SAF2014‐56763‐R), Asociación Española Contra el Cáncer, Generalitat Valenciana (PrometeoII/2014/076 and ISIC) and EU (FP6‐029192). R.L. thanks the Chilean Ministry of Education CONICYT (PhD Scholarship: BECA CHILE) for financial suppor

    Structure and magnetic properties of the AB(HCO2)3 (A = Rb+ or Cs+, B = Mn2+, Co2+ or Ni2+) frameworks: probing the effect of size on the phase evolution of the ternary formates

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    This work reports the synthesis and structures of six new AB(HCO2)3 (A = Rb+ or Cs+ and B = Mn2+, Co2+ or Ni2+) frameworks containing the largest monoatomic cations on the A-site. RbMn(HCO2)3 is found to adopt a distorted perovskite framework with a 412[middle dot]63 topology and a mixture of syn-anti and anti-anti ligands, while the remaining compounds adopt a chiral hexagonal structure with a 49[middle dot]66 topology. The structures of these frameworks clarify the effect of ionic size on the formation of the five known architectures adopted by the AB(HCO2)3 frameworks, which have attracted attention as a new class of potential multiferroics, and in particular the chiral hexagonal structure within this. This also highlights the role of molecular A-site cations in stabilising the 49[middle dot]66 topology for frameworks where such cations are too large or small to support this structure on the basis of size alone, possibly due to hydrogen bonding. The magnetic properties of the RbB(HCO2)3 and CsMn(HCO2)3 frameworks are also reported with the Rb+ compounds featuring weak ferromagnetic behaviour and the latter being purely antiferromagnetic. In conjunction with a comparison of the other isostructural AB(HCO2)3 frameworks we find that compounds adopting the 49[middle dot]66 topology have much higher magnetic ordering temperatures than those with the RbMn(HCO2)3 structure, highlighting the importance of understanding the structure-property relationships of the ternary formates

    Multistimuli Response Micro- and Nanolayers of a Coordination Polymer Based on Cu2I2 Chains Linked by 2-Aminopyrazine

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    This is the peer reviewed version of the following article: Conesa‐Egea, J., Gallardo‐Martínez, J., Delgado, S., Martínez, J. I., Gonzalez‐Platas, J., Fernández‐Moreira, V., ... & Amo‐Ochoa, P. Multistimuli Response Micro‐and Nanolayers of a Coordination Polymer Based on Cu2I2 Chains Linked by 2‐Aminopyrazine. Small 13.33 (2017): 1700965 , which has been published in final form at https://doi.org/10.1002/smll.201700965. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived VersionA nonporous laminar coordination polymer of formula [Cu2I2(2-aminopyrazine)]n is prepared by direct reaction between CuI and 2-aminopyrazine, two industrially available building blocks. The fine tuning of the reaction conditions allows obtaining [Cu2I2(2-aminopyrazine)]n in micrometric and nanometric sizes with same structure and composition. Interestingly, both materials show similar reversible thermo- and pressure-luminescent response as well as reversible electrical response to volatile organic solvents such as acetic acid. X-ray diffraction studies under different conditions, temperatures and pressures, in combination with theoretical calculations allow rationalizing the physical properties of this compound and its changes under physical stimuli. Thus, the emission dramatically increases when lowering the temperature, while an enhancement of the pressure produces a decrease in the emission intensity. These observations emerge as a direct consequence of the high structural flexibility of the Cu2I2 chains which undergo a contraction in Cu-Cu distances as far as temperature decreases or pressure increases. However, the strong structural changes observed under high pressure lead to an unexpected effect that produces a less effective Cu-Cu orbital overlapping that justifies the decrease in the intensity emission. This work shows the high potential of materials based on Cu2I2 chains for new applicationsThe authors thank financial support from the Spanish Ministerio de Economía y Competitividad (MAT2013-46502-C2-2P, MAT2016-77608-C3-1-P, MAT2016-75883-C2-2-P, MAT2010-20843-C02-01, MAT2016-75586-C4-4-P, CTQ2016-75816-C2-1P), also thank the scientific computing center (CCC) of the Autonoma University of Madrid for their time. J.I.M. acknowledges the financial support by the Ramón y Cajal Program of MINECO (Grant RYC-2015-17730) and the EU via the ERC-Synergy Program (Grant ERC-2013-SYG-610256 NANOCOSMOS

    Mononuclear and Mixed-Metal Dimethyltin Pacman Complexes of a Schiff-Base Pyrrole Macrocycle

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    The synthesis of the dialkyltin complex [SnMe2-(H2L)] of an octadentate Schiff-base pyrrol macrocycle is described in which the gross Pacman geometry enforces structural discrimination between the two methyl groups. The presence of the metal-free compertment engenders the formation of mixed-metal Sn-Fe and Sn-Zn complexes in which the macrocyclic cleft has distorted considerably upon the introduction of the transition metal cation.</p

    Synthesis of Bimetallic Uranium and Neptunium Complexes of a Binucleating Macrocycle and Determination of the Solid-State Structure by Magnetic Analysis

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    Syntheses of the bimetallic uranium(III) and neptunium(III) complexes [(UI)2(L)], [(NpI)2(L)], and [{U(BH4)}2(L)] of the Schiff-base pyrrole macrocycles L are described. In the absence of single-crystal structural data, fitting of the variable-temperature solid-state magnetic data allows the prediction of polymeric structures for these compounds in the solid state.JRC.E.6-Actinides researc
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