2,2′-(Propane-1,3-di­yl)bis­(2H-indazole)

The title mol­ecule, C17H16N4, is a bis-indazole crystallized in the rare 2H-tautomeric form. Indazole heterocycles are connected by a propane C3 chain, and the mol­ecule is placed on a general position, in contrast to the analogous compound with a central C2 ethane bridge, which was previously found to be placed on an inversion center in the same space group. In the title mol­ecule, indazole rings make a dihedral angle of 60.11 (7)°, and the bridging alkyl chain displays a trans conformation, resulting in a W-shaped mol­ecule. In the crystal, mol­ecules inter­act weakly through π–π contacts between inversion-related pyrazole rings, with a centroid–centroid separation of 3.746 (2) Å

N,N′-Bis(2-ammonio­benz­yl)ethane-1,2-diammonium–nitrate–perchlorate (1/1.5/2.5)

The title compound, C16H26N4 4+·2.5ClO4 −·1.5NO3 −, is an organic salt in which the cation is a fully protonated tetra­mine. The cation lies on an inversion center and, as a consequence, both benzene rings are parallel. The central chain is found in an all-trans arrangement, a conformation different from that observed in the crystal structure of the non-protonated mol­ecule. The charges are balanced by a mixture of nitrate and perchlorate ions. One site is occupied by an ordered perchlorate ion, while the other contains both nitrate and perchlorate ions, with occupancies of 0.75 and 0.25, respectively. In the crystal, the NH2 + groups of the cation form N—H⋯O hydrogen bonds with the anions. The NH3 + groups also behave as donor groups, allowing the building of chains along [100], alternating cations and disordered anions being connected via N—H⋯O hydrogen bonds

Polyaza macroligands as potential agents for heavy metal removal from wastewater

Two polyaza macroligands N,N´-bis(2-aminobenzyl)-1,2- ethanediamine (L1) and 3,6,9,12-tetraaza-4(1,2),11(1,2)-dibenzo-1(1,3)- piridinaciclotridecafano (L2) were characterized and investigated for their metal ion extraction capabilities. The nature of all complexes was established by spectroscopic techniques. The equilibrium constants were determined by spectrophotometric and potentiometric techniques and the residual concentration of metals in the solutions by Atomic Absorption Spectrometry (AAS). The capacity of the ligands to remove heavy metals such as Cu(II), Ni(II), Cd(II), Zn(II) and Pb(II) as insoluble complexes was evaluated in wastewater from industrial effluents. These agents showed high affinity for the studied metals. The values of equilibrium constants of the isolated complexes (between 1 x 104 and 2 x 107) demonstrated the feasibility of applying these chelating agents as an alternative to remove heavy metals from industrial effluents

Tris{2-[(2-amino­benzyl­idene)amino]­ethyl}amine

The title Schiff base, C27H33N7, is a tripodal amine displaying C 3 symmetry, with the central tertiary N atom lying on the threefold crystallographic axis. The N—CH2—CH2—N conformation of the pendant arms is gauche [torsion angle = 76.1 (3)°], which results in a claw-like mol­ecule, with the terminal aniline groups wrapped around the symmetry axis. The lone pair of the apical N atom is clearly oriented inwards towards the cavity, and should thus be chemically inactive. The amine NH2 substituents lie in the plane of the benzene ring to which they are bonded. With such an arrangement, one amine H atom forms an S(6) motif through a weak N—H⋯N hydrogen bond with the imine N atom, while the other is engaged in an inter­molecular N—H⋯π contact involving the benzene ring of a neighbouring mol­ecule related by inversion. The benzene rings also participate in an intra­molecular C—H⋯π contact of similar strength. In the crystal structure, mol­ecules are separated by empty voids (ca 5% of the crystal volume), although the crystal seems to be unsolvated

2,2′-(2,6-Pyridinedi­yl)diquinoline

The title mol­ecule, C23H15N3, is a terpyridine derivative resulting from the Friedländer annulation between 2,6-diacetyl­pyridine and N,N′-bis­(2-amino­benz­yl)ethyl­ene­di­amine. The asymmetric unit contains one half-mol­ecule, the complete mol­ecule being generated by a mirror plane (one N atom and one C atom lie on the plane). The mol­ecule, although aromatic, is deformed from planarity as a result of crystal packing forces: mol­ecules are stacked along the short c axis, with a short separation of 3.605 (1) Å between the mean planes. The bent mol­ecular shape is reflected in the dihedral angle of 16.10 (5)° between the essentially planar quinoline groups. In addition to π⋯π inter­actions, the crystal structure features weak inter-stack C—H⋯N contacts involving atoms of the central pyridine rings which lie in a common crystallographic m plane

N,N′-Bis(2-aza­niumylbenz­yl)ethane-1,2-diaminium tetra­chloride

The title compound, C16H26N4 4+·4Cl−, is based on a fully protonated tetra­amine. In the cation, both benzene rings are connected by an all-trans chain, and the rings are almost parallel, with an angle between the mean planes of 8.34 (12)°. The benzene rings are arranged in such a way that the NH3 + substituents are oriented cis with respect to the central chain. This arrangement is a consequence of multiple N—H⋯Cl hydrogen bonds, involving all N—H groups in the cation and the four independent Cl− anions. These contacts have strengths ranging from weak to strong (based on H⋯Cl separations), and generate a complex three-dimensional crystal structure with no preferential crystallographic orientation for the contacts

N,N′-Bis(2-amino­benz­yl)ethane-1,2-diaminium bis­(4-methyl­benzene­sulfonate)

The title salt, C16H24N4 2+·2C7H7O3S−, crystallizes with the dication situated on an inversion center and the anion in a general position. The cation contains two ammonium and two free amine groups, and the observed conformation for the chain linking the benzene rings is different from that found in the free tetra­amine and in the fully protonated tetra­amine. All amine and ammonium H atoms of the cation form hydrogen bonds with eight symmetry-related anions, using the sulfonate O atoms as acceptors. This arrangement for the ions precludes any π–π contacts between benzene rings in the crystal

CuInS2 thin films obtained through the annealing of chemically deposited In2S3–CuS thin films.

In this work, we report the formation of CuInS2 thin films on glass substrates by heating chemically deposited multilayers of copper sulfide (CuS) and indium sulfide (In2S3) at 300 and 350 ◦C in nitrogen atmosphere at 10 Torr. CIS thin films were prepared by varying the CuS layer thickness in the multilayers with indium sulfide. The XRD analysis showed that the crystallographic structure of the CuInS2 (JCPDS27-0159) is present on the deposited films. From the optical analysis it was estimated the band gap value for the CIS film (1.49 eV). The electrical conductivity varies from 3 × 10−8 to 3 −1 cm−1 depending on the thickness of the CuS film. CIS films showed p-type conductivity

Evidence of spatial clustering of childhood acute lymphoblastic leukemia cases in Greater Mexico City: report from the Mexican Inter-Institutional Group for the identification of the causes of childhood leukemia

BackgroundA heterogeneous geographic distribution of childhood acute lymphoblastic leukemia (ALL) cases has been described, possibly, related to the presence of different environmental factors. The aim of the present study was to explore the geographical distribution of childhood ALL cases in Greater Mexico City (GMC).MethodsA population-based case-control study was conducted. Children <18 years old, newly diagnosed with ALL and residents of GMC were included. Controls were patients without leukemia recruited from second-level public hospitals, frequency-matched by sex, age, and health institution with the cases. The residence address where the patients lived during the last year before diagnosis (cases) or the interview (controls) was used for geolocation. Kulldorff’s spatial scan statistic was used to detect spatial clusters (SCs). Relative risks (RR), associated p-value and number of cases included for each cluster were obtained.ResultsA total of 1054 cases with ALL were analyzed. Of these, 408 (38.7%) were distributed across eight SCs detected. A relative risk of 1.61 (p<0.0001) was observed for the main cluster. Similar results were noted for the remaining seven ones. Additionally, a proximity between SCs, electrical installations and petrochemical facilities was observed.ConclusionsThe identification of SCs in certain regions of GMC suggest the possible role of environmental factors in the etiology of childhood ALL

Análisis de muestras complejas de ácidos carboxílicos y carbohidratos mediante GC - MS

Los ácidos ?-hidroxicarboxílicos y carbohidratos son compuestos que se encuentran en la naturaleza, o que se pueden generar durante procesos como la hidrólisis o fermentación de productos de origen natural. En este trabajo se presenta un método para el análisis de seis ácidos carboxílicos y cinco carbohidratos en un hidrolizado de cáscara de arroz, mediante cromatografía de gases capilar con detector de espectrometría de masas (GC/MS). Se establecieron las condiciones óptimas de operación del equipo para una separación completa de los compuestos en el menor tiempo posible, permitiéndonos su cuantificación mediante la técnica de adición de estándar-estándar interno. Los estándares y muestra fueron derivatizados para poder ser analizados por GC/MS, se obtuvieron concentraciones que fluctúan entre los 0.099 y 2.84% P/V