Synthesis of a Heterometallic [Zn2Ca] Pinwheel Array Stabilized by Amide-Amide Synthons

The rational design of heterometallic compounds bearing s-block metal ions have been a difficult task for chemists owing to their lack of preferential geometries. However, some strategies, such as the design of coordinating pockets with different sizes and/or donor atoms, have offered great results. In this work, this strategy has been tested using Ca(II) as an s-block metal ion and a compound previously obtained by our group with the formula [Zn(μ-ACA)(4-phpy)], which contains tetrahedral N,O- and octahedral O-coordinating pockets as a model structure. From this work, the corresponding heterometallic compound with the formula [ZnCa(μ-ACA)(4-phpy)]·EtOH (1) has been successfully synthesized, and fully characterized, and its crystal structure has been elucidated. Furthermore, we have compiled all the crystal structures containing [ZnM] pinwheel secondary building units (SBUs), where M stands for an s-block metal ion, and the observed tendencies, as well as the promising applications as template SBUs for the preparation of 1D-3D coordination polymers, have been discussed. Finally, solid-state UV-Vis and photoluminescence have been recorded and compared with the homometallic [Zn(μ-ACA)(4-phpy)] compound

Single-crystal ac susceptibility measurements on [Co(NH3)6][CuCl5], a 3D, S=1/2 Heisenberg antiferromagnet

Under the terms of the Creative Commons Attribution (CC BY) license to their work.Single-crystal ac magnetic susceptibilities of [Co(NH3)6][CuCl5] along the three crystallographic axes in the temperature range from 1.1 to 90 K are presented. The magnetic behavior is characteristic of a three-dimensional antiferromagnet, its ordering temperature being at Tc=3.8 K. Susceptibilty data can be fit to a Heisenberg S=1/2 simple cubic model using high-temperature series expansions extrapolated with Pade approximants. Good agreement is found for an exchange constant J/kB=-3.13 K and values of g factor ga=2.09, g b=gc =2.04, a,b, and c being the crystallographic axes. This result makes [Co(NH3)6][CuCl5] one of the few examples of a 3D antiferromagnetic Heisenberg S=1/2 model. The magnetic behavior below Tc indicates the existence of crystallographic domains due to the structural transition from cubic to tetragonal symmetry that the system has at about 280 K.The research in Zaragoza and Barcelona has been supported respectively by grants 3380/83 and 409/84, from the Comision Asesora de Investigacion Cientifica y Technica of the Ministerio de Educacion y Ciencia. The research in Chicago has been supported by Grant No. DMR· 8515224 from the Solid State Chemistry Program, Division of Materials Research of the National Science Foundation. Cooperative work has been supported by grant CCB-8504/001 from the American-Spain Joint Committee for Technical and Scientific Cooperation. One of us (M. C. M.) wants also to acknowledge a student fellowship from the Ministerio de Educacion y Ciencia.Peer Reviewe

Bimetallic derivatives of the [M(en)3]3+ ion (M=Cr and Co): A series of compounds with unusual magnetic and structural properties (abstract)

Under the terms of the Creative Commons Attribution (CC BY) license to their work.The crystal structure and magnetic susceptibility of a series of [M(en)3]3+ (M=Cr or Co) derivatives are described. In particular, the crystalline structures of (1) [Cr(en) 3]3[FeCl6]Cl6·H2O, (2) [Co(en)3]3[FeCl6]Cl6· H2O, and (3) [Cr(en)3][FeCl6]·11H 2O are reported. Structural data, in Å, for these compounds are as follows: (1) space group R3, a=15.447(4), c=21.060(6), Z=3; (2) space group R3, a=15.346(3), c=20.880(5), Z=3; (3) space group P3c1, a=11.654(3), c=15.508(4), Z=2. The main structural feature of the first two isomorphous materials is that they consist of a three-dimensional network of triangular antiprisms formed by the [M(en)3]3+ (M=Cr or Co) ions and connected with each other by sharing corners. An [FeCl 6]3- ion is placed at the center of each antiprism. Compound (3) contains a sc arrangement of [Cr(en)3] 3+ and [FeCl6]3- octahedra. In addition, the magnetic susceptibilities of the above-mentioned isomorphous compounds and of [M(en)3][FeCl6] (M=Cr and Co) and [Cr(en)3][InCl6] are reported. While [Cr(en) 3]3[FeCl6]Cl6·H2O orders as a ferrimagnet at 0.91 K, [Cr(en)3][FeCl6] exhibits antiferromagnetic properties with Tc=2.26 K, a temperature rather similar to the antiferromagnetic ordering temperature of [Co(en) 3][FeCl6].Peer Reviewe

Ni-, Pt- and (Ni/Pt)-doped TiO₂ nanophotocatalysts : a smart approach for sustainable degradation of Rhodamine B dye

Ni (1 wt%)-, Pt (1 wt%)- and [Ni (0.5 wt%)/Pt (0.5 wt%)]-doped TiO₂ nanoporous catalysts have been successfully obtained through a facile two-step hydrothermal route. TiO₂ crystallizes mostly in the anatase phase and acts as a mesoporous matrix. Meanwhile, Ni, Pt and Ni/Pt dopants form small nanoparticles (NPs) (3-95 nm in diameter) which are hosted by the TiO₂ framework. The resulting composites exhibit a rather large surface area, in the range of 186-200 m2/g. The band gap energy reduces from 3.03 eV for the undoped TiO₂ to 2.15 eV for the Pt-loaded TiO₂. As a consequence, absorption expands toward the visible light range. The photodegradation of Rhodamine B dye in aqueous medium has been investigated under UV-vis light irradiation. The presence of Ni, Pt and Ni/Pt NPs significantly enhances the photocatalytic activity of the material. Furthermore, the Ni-doped TiO₂ shows ferromagnetic behavior at room temperature, which makes its recovery and subsequent fast reutilization possible. Interestingly, this sample also exhibits the best stability upon recycling. Considering all the current challenges in sustainable water remediation, these new photocatalysts could find applications in real environmental contexts in the near future

Efecto de los antimaláricos sobre los diferentes dominios del índice de daño SLICC en pacientes de la cohorte GLADEL

Objetivos: estimar el efecto de los antimaláricos (AM) sobre los diferentes dominios del índice de daño SLICC (SDI). Métodos: se estudiaron pacientes con diagnóstico clínico reciente (≤2 años) de lupus eritematoso sistémico (LES) de la cohorte GLADEL

Multifunctional system based on hybrid nanostructured rod formation, for sensoremoval applications of Pb2+ as a model toxic metal

A new and simple multifunctional system based on hybrid calcite-poly(ethyleneimine) (PEI) nanostructured rod (NR) formation, which shows as a proof-of-concept the sensing and removal (sensoremoval concept) of Pb 2+ as a model toxic metal for environmental applications, has been developed. The addition of Na2CaEDTA and Na2CO3 solutions to Pb2+ contaminated water leads to the crystallization of calcite-PEI NRs. These NRs are composed of self-assembled hexagonal plate-like shapes of around 450 nm. The formed calcite-PEI NRs in suspension permit Pb 2+ detection, through a simple turbidimetric measurement, and at the same time act as a Pb2+ remover. This sensing and removal system is able to detect up to 1 ppm Pb2+ (1-1000 ppm linear range) and reaches an adsorption capacity of 240 mg Pb2+ per g of NRs, as evaluated using a 342 ppm initial Pb2+ concentration at pH 4 after 30 min incubation time. The maximum Pb2+ removal capacity reported here is higher than other capacities reported previously, using materials that are not as cheap and biodegradable as calcite. The Pb2+ detection range found for this system is suitable to evaluate levels of metal contamination from industrial wastewater of around 1-100 ppm. This system based on an advanced biodegradable material constitutes a useful tool as a proof-of-concept in the design of future multifunctional platforms for the development of integrated environmental technologies with sensing and remediation functions. This journal is © The Royal Society of Chemistry 2013.MICINN (Spain) for Spain-Japan International Bilateral PIB2010JP-00278 projects is acknowledged. A. Lopez-Marzo thanks the Generalitat of Catalunya for the FI-2010 scholarship.Peer Reviewe

The crystal structure and molecular structures of twinned [Cr(NH3)6] [Ni(H2O)6]Cl5 . 1/2(NH4Cl): A new complex bimetallic compound

The complex bimetallic salt crystallizes in the space group Fd3 with a = 20.440(2) Å and Z = 16. The crystal and molecular structures have been determined from single crystal data, despite a systematic twinning (RF = 0.037, RI = 0.041 for 1065 reflections). The spatial arrangement consists in discrete [Cr(NH3)6]3+, [Ni(H2O)6]2+, Cl−, and NH+4 ions, held together by ionic forces and by a network of hydrogen bonds. Both chromium and nickel ions are in octahedral sites. Structural correlations with related compounds are examined.This work was partially supported by Grant MAT88-176 from the Comision Interministerial de Ciencia y Tecnologia and by a grant from the Spanish-French Committee for Scientific Cooperation. One of us (M.C.M.) is grateful for the receipt of a NATO Postdoctoral Fellowship and for finantial support given by the CNRS (France).Peer Reviewe

Extremely fast and high Pb2+ removal capacity using a nanostructured hybrid material

Ultra-fast toxic metal removal using a hybrid and nanostructured vaterite-poly(ethyleneimine) (NV-PEI) is reported. Especially for Pb 2+, an extremely high and fast adsorption capacity without precedents is observed. Within a 3 min contact time (CT), 97-100% of Pb2+ contaminant in water samples at pH 6, with a large concentration range (from 2 to 1000 ppm) and using a dosage of 0.5 g NV-PEI per L, has been removed. The maximum adsorption capacity (qmax) calculated for a 1500 ppm Pb 2+ initial concentration was 2762 mg of Pb2+ per g NV-PEI. In addition to the excellent Pb2+ removal, this material is cheap, easy to synthesize, biocompatible, and biodegradable, which makes it superior to others reported to date and an attractive alternative for the treatment of industrial wastewaters.MICINN MAT2011-25870 and Spain-Japan International Bilateral PIB2010JP-00278 projects are acknowledged. A. Lopez Marzo thanks Generalitat of Catalunya for the FI-2010 scholarship given.Peer Reviewe

Magnetic properties of the low-temperature ferrimagnet [Cr(H2O)(NH3)5][FeCl6]

We report on the magnetic properties of the complex bimetallic compound [Cr(H2O)(NH3)5][FeCl6] studied by ac magnetic susceptibility and magnetization techniques in the range 1.5-30 K and 0-40 kOe. The crystal structure contains discrete [Cr(H2O)(NH3)5]3+ and [FeCl6]3- ions, held together by ionic forces and by a network of hydrogen bonds. At temperatures below (2.32±0.01) K the compound seems to behave as a noncollinear ferrimagnet. In addition, the experimental H-T magnetic phase diagram has been derived.The research has been supported by Grants CAICYT 3380/83 and CICYT MAT 88-0174.Peer Reviewe

Nanostructured CaCO3-poly(ethyleneimine) microparticles for phenol sensing in fluidic microsystem

A new and simple strategy based on nanostructured CaCO3-poly(ethyleneimine) (PEI) microparticles (MPs) for phenol sensing using PDMS/glass fluidic microchip is developed. This fluidic microsystem including integrated screen-printed electrodes modified with CaCO3-PEI MPs and tyrosinase (Tyr) through cross-linking with glutaraldehyde, represents a low-cost platform for phenol detection. The designed fluidic microsystem improves the sensitivity of the biosensor allowing the detection of very low concentrations of phenol (up to 10 nM). This device shows high repeatability and low detection limit, is easy to be fabricated, inexpensive, disposable, and amenable to mass production. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.This work is supported by theMICINN (Spain) grant for the Spain-Japan International Bilateral PIB2010JP-00278 project. A.L.M. thanks the Generalitat of Catalunya for the FI2010 predoctoral scholarship given. L.H. and J.L. thank the support of the Scientific Grant Agency VEGA of the Slovak Republic (Project 1/0182/11).Peer Reviewe