Unprecedented layered coordination polymers of dithiolene group 10 metals: Magnetic and electrical properties

One-pot reactions between Ni(ii), Pd(ii) or Pt(ii) salts and 3,6-dichloro-1,2-benzenedithiol (HSC6H2Cl2SH) in KOH medium under argon lead to a series of bis-dithiolene coordination polymers. X-ray analysis shows the presence of a common square planar complex [M(SC6H2Cl2S)2]2- linked to potassium cations forming either a two-dimensional coordination polymer network for {[K2(μ-H2O)2(μ-thf)(thf)2][M(SC6H2Cl2S)2]}n [M = Ni (1) and Pd (2)] or a one-dimensional coordination polymer for {[K2(μ-H2O)2(thf)6][Pt(SC6H2Cl2S)2]}n (3). In 3 the coordination environment of the potassium ions may slightly change leading to the two-dimensional coordination polymer {[K2(μ-H2O)(μ-thf)2][Pt(SC6H2Cl2S)2]}n (4) that crystallizes together with 3. The physical characterization of compounds 1-3 show similar trends, they are diamagnetic and behave as semiconductorsWe thank financial support from MICINN (MAT2013-46753-C2-1-P, CTQ2014-52758-P and MAT2014-56143-R) and Generalitat Valenciana (PrometeoII/2014/076

A minireview on covalent organic frameworks as stationary phases in chromatography

Advances in the design of novel porous materials open new avenues for the development of chromatographic solid stationary phases. Covalent organic frameworks (COFs) are promising candidates in this context due to their remarkable structural versatility and exceptional chemical and textural properties. In this minireview, we summarize the main strategies followed in recent years to apply these materials as stationary phases for chromatographic separations. We also comment on the perspectives of this new research field and potential directions to expand the applicability and implementation of COF stationary phases in analytical systems

Covalent organic frameworks based on Schiff-base chemistry: Synthesis, properties and potential applications

Covalent organic-frameworks (COFs) are an emerging class of porous and ordered materials formed by condensation reactions of organic molecules. Recently, the Schiff-base chemistry or dynamic imine-chemistry has been widely explored for the synthesis of COFs. The main reason for this new tendency is based on their high chemical stability, porosity and crystallinity in comparison to previously reported COFs. This critical review article summarizes the current state-of-the-art on the design principles and synthetic strategies toward COFs based on Schiff-base chemistry, collects and rationalizes their physicochemical properties, as well as aims to provide perspectives of potential applications which are at the forefront of research in materials scienceFinancial support from Spanish Government (Project MAT2014-52305-P and MAT2013-46753-C2-1-P) and a UCM-BSCH joint project (GR3/14) is acknowledge

Structural study of the compounds formed in the reactions of FeCl3·6H2O with Ni(OH)2 in the presence of dithiolenes HSRSH (R = C6H2Cl2 or C6H4)

In our attempts to prepare coordination polymers by reaction of FeCl3·6H2O and Ni(OH)2 in the presence of dithiolenes HSC6H2X2SH (X = Cl or H), several ion pairs of compounds containing the anionic entity [Ni(SC6H2X2S)2]⁻ were obtained instead. It was also found that other species without dithiolene ligands were formed in these reactions, giving rise to different ion pairs and a tetrametallic cluster. The careful isolation of the different types of crystalline solids allowed the characterization of all of the resulting compounds by single crystal X-ray diffraction (SCXRD). In order to establish the amount of nickel and iron present in the crystals, complementary total reflection X-ray fluorescence (TXRF) analyses were performed. The eight different structural types that were obtained are described and compared with related ones found in the literaturaThis research was funded by the Spanish Ministerio de Economía y Competitividad, grand number (MAT2016-77608-C3-1-P) and Ministerio de Ciencia, Innovación y Universidades (PGC2018-094644-B-C21

Luminescent Thermochromism of 2D Coordination Polymers Based on Copper(I) Halides with 4-Hydroxythiophenol

This is the peer-reviewed version of the following article: Troyano, J., Perles, J., Amo‐Ochoa, P., Martínez, J. I., Concepción Gimeno, M., Fernández‐Moreira, V., ... & Delgado, S. (2016). Luminescent Thermochromism of 2D Coordination Polymers Based on Copper (I) Halides with 4‐Hydroxythiophenol. Chemistry–A European Journal, 22(50), 18027-18035., which has been published in final form at https://doi.org/10.1002/chem.201603675. This article may be used for non-commercial purposes in accordance with Wiley-VCH Terms and Conditions for Self-ArchivingSolvothermal reactions between copper(I) halides and 4-mercaptophenol give rise to the formation of three coordination polymers with general formula [Cu3X(HT)2]n(X=Cl, 1; Br, 2; and I, 3). The structures of these coordination polymers have been determined by X-ray diffraction at both room- and low temperature (110 K), showing a general shortening in Cu−S, Cu−X and Cu−Cu bond lengths at low temperatures. 1 and 2 are isostructural, consisting of layers in which the halogen ligands act as μ3-bridges joining two Cu1 and one Cu2 atoms whereas in 3 the iodine ligands is as μ4-mode but the layers are quasi-isostructural with 1 or 2. These compounds show a reversible thermochromic luminescence, with strong orange emission for 1 and 2, but weaker for 3 at room temperature, whereas upon cooling at 77 K 1 and 2 show stronger yellow emission, and 3 displays stronger green emission. DFT calculations have been used to rationalize these observations. These results suggest a high potential for this novel and promising stimuli-responsive materialsThis work was supported by MICINN (MAT2013-46753-C2-1-P). JIM acknowledges funding from the ERC-Synergy Program (Grant ERC-2013-SYG-610256 NANOCOSMOS) and computing resources from CTI-CSIC

Insulin sensor based on nanoparticle-decorated multiwalled carbon nanotubes modified electrodes

Insulin sensors based on glassy carbon electrodes modified with nafion-multiwalled carbon nanotubes decorated with nickel hydroxide nanoparticles (Ni(OH)<inf>2</inf>NPs/Nafion-MWCNTs/GC), were prepared by electrochemical deposition of Ni(OH)<inf>2</inf>NPs from a dinuclear paddle-wheel Ni monothiocarboxylate complex on the MWCNTs/GC surface. The size and distribution of the Ni(OH)<inf>2</inf>NPs/Nafion-MWCNTs were characterized by transmission electron microscopy (TEM). The results show that Ni(OH)<inf>2</inf> nanoparticles were electrodeposited on the surface of carbon nanotubes. Moreover, the electrochemical behavior of the modified electrodes in aqueous alkaline solutions of insulin was studied by cyclic voltammetry and chronoamperometry. It was found that the as-prepared nanoparticles have excellent electrocatalytic activity towards insulin oxidation due to their special properties, reducing the overpotential and improving the electrochemical behavior, compared to the bare GC electrode. Amperometry was used to evaluate the analytical performance of modified electrode in the determination of insulin. Excellent analytical features, including high sensitivity (5.0 A mol cm<sup>-2</sup> μM<sup>-1</sup>), low detection limit (85 nM) and wide dynamic range (up to 10.00 μM), were achieved under optimum conditions. Moreover, these insulin sensors show good repeatability and a high stability after successive potential cycling. Common substances such as ascorbic acid, uric acid and acetaminophen do not interfere. Finally, the developed sensors have been applied to the determination of insulin in pharmaceuticals and in human plasma. Efficient recoveries for pharmaceuticals and human plasma demonstrate that the proposed methodology can be satisfactorily applied to these types of samplesThe authors acknowledge Ministerio de Economía y Competitividad (project No. CTQ2014-53334-C2-1-R and MAT2013-46753-C2-1-P) and Comunidad de Madrid (NANOAVANSENS Program) for financial support. E.M.P. gratefully acknowledges the FPU-2010 Grant from the Ministerio de Educació

Stability and electronic structure of M-DNA: Role of metal position

We investigate, by first-principles density-functional calculations, fragments and periodic helices of CG- and AT-DNA, modified by incorporation of Zn2+ cations. We study the relative stability of different binding sites for the metal ions as well as different methods of charge neutralization. We find that binding the Zn cation to the N(7) atom of guanine or adenine leads always to lower energies than substitution of an imino proton between two H-bonded bases. Also, neutralizing with OH- groups bonded to Zn2 + is more stable than removing protons from the phosphate groups. Contrarily to common wisdom, we find that planarity of the base pairs is not an essential factor of stability, and that nonplanar base pairs can also be stacked effectively. Finally, we find that the most stable CG and AT helices, with Zn2+ bonded to N(7) atoms and neutralized by OH- ions, have wide band gaps of more than 2 eV, and we conclude that they are poor candidates for electronic conductionThis work has been supported by Brazilian agencies: Fapemig, CNPq, and Ministerio da Ciencia e Tecnologia; by Grants FIS2009-12712, MAT2010-20843-C02-01, and CSD2007-00050 of the Spanish Ministry of Science and Innovation; and by European Grant EU(FP6-029192

Volume-conservative modeling of structures manufactured by molten drop-on-drop deposition

An improved analytic model to accurately determine the geometry of structures manufactured by molten drop-on-drop deposition is presented. This deposition mode allows quasi-spherical deposited droplets to be achieved and precise control over the geometry of the final manufactured structures. The model exactly conserves the volume of the deposited material and matches the solidification contact angle between consecutive deposited droplets, providing a precise geometrical description of the manufactured structures. The proposed model is validated using results of experiments performed with several materials for the deposited droplets and substrate, and droplet radii ranging from 40 to 800 m. A good degree of agreement was found between theoretical and experimental results. A comparison with the well-established Gao&Sonin model shows that the proposed model represents a major improvement, and may be of great practical interest in industrial applications.The authors gratefully acknowledge the joint support of the Spanish Ministerio de Ciencia, Innovación y Universidades - Agencia Estatal de Investigación and FEDER through projects DPI2017-87826-C2-1-P and DPI2017-87826-C2-2-P, and the Spanish Ministerio de Ciencia e Innovación - Agencia Estatal de Investigación (MCIN/ AEI/ 10.13039/501100011033) through projects PID2020-120100GB-C21 and PID2020-120100GB-C22

Layered copper-metallated covalent organic frameworks for huisgen reactions

Covalent organic frameworks (COFs) are porous materials formed through condensation reactions of organic molecules via the formation of dynamic covalent bonds. Among COFs, those based on imine and β-ketoenamine linkages offer an excellent platform for binding metallic species such as copper to design efficient heterogeneous catalysts. In this work, imine- and β-ketoenamine-based COF materials were modified with catalytic copper sites following a metallation method, which favored the formation of binding amine defects. The obtained copper-metallated COF materials were tested as heterogeneous catalysts for 1,3-dipolar cycloaddition reactions, resulting in high yields and recyclabilityThis work was supported by PID2019-106268GB-C32 and RTI2018-096138-A-I00 funded by MCIN/AEI/10.13039/ 501100011033 and EUR2020-112294 funded by MCIN/ AEI/10.13039/501100011033 and by the European Union “NextGenerationEU”/PRTR. A.E.P.-P. and F.Z. acknowledge the financial support from the Spanish Ministry of Science and Innovation, through the “María de Maeztu” Programme for Units of Excellence in R&D (CEX2018-000805-M). A.E.P.-P. acknowledges the Spanish Ministry of Science and Innovation for a Ramón y Cajal fellowship (RYC2018-024328-I). The authors acknowledge beamline P02.1 at DESY (proposal I 20190208 EC), a member of the Helmholtz Association (HGF). They thank Dr. Michael Wharmby for his assistance during the experiment at P02.1. The research leading to this result has been supported by the project CALIPSOplus under the Grant Agreement 730872 from the EU Framework Programme for Research and Innovation HORIZON 2020. I.R.-M. acknowledges an FPI-UAM 2019 fellowship from Universidad Autónoma de Madrid. P.A. acknowledges the financial support from “Ayudas para Contratos Predoctorales para la Formación de Doctores” Program of MINECO (Grant BES-2017-070838