A family of Cd(II) coordination polymers constructed from 6-aminopicolinate and bipyridyl co-linkers: study of their growth in paper and photoluminescence sensing of Fe and Zn ions.

In this work, we report on five novel coordination polymers (CPs) based on the linkage of the [Cd(6apic)] building block [where 6apic = 6-aminopicolinate] by different bipyridine-type organic spacers, forming different coordination compounds with the following formulae: [Cd(μ-6apic)] (1), {[Cd(6apic)(μ-bipy)]·HO} (2), {[Cd(6apic)(μ-bpe)]·2HO} (3), [Cd(6apic)(μ-6apic)(μ-bpa)] (4) and {[Cd(6apic)(μ-tmbp)]·7HO} (5) [where bipy = 4,4'-bipyridine, bpe = 1,2-di(4-pyridyl)ethylene, bpa = 1,2-di(4-pyridyl)ethane (bpa) and tmbp = 1,3-di(4-pyridyl)propane]. Most of the synthesized compounds form infinite metal-organic rods through the linkage of the building block by the bipyridine-type linker, except in the case of compound 4 whose assembly forms a densely packed 3D architecture. All compounds were fully characterized and their photoluminescence properties were studied experimentally and computationally through density functional theory (DFT) calculations.

Cerium(III) and 5-methylisophthalate-based MOFs with slow relaxation of magnetization and photoluminescence emission.

Two novel Ce(III) metal organic frameworks (MOFs) with formulas [Ce(5Meip)(H-5Meip)]GR-MOF-17 and [CeCl(5Meip)(DMF)]GR-MOF-18 (5Meip = 5-methylisophthalate, DMF = ,-dimethylformamide) have been synthesized, forming 3-dimensional frameworks. Magnetic measurements show that both compounds present field-induced slow magnetic relaxation under a small applied dc field. For GR-MOF-17, the temperature dependence of relaxation times is best described by a Raman mechanism, whereas for GR-MOF-18, relaxation occurs through a combination of Raman and local-mode pathways.

Synthesis, Characterization, and Catalytic Performance of a New Heterobimetallic Y/Tb Metal-Organic Framework with High Catalytic Activity.

A three-dimensional heterobimetallic porous structure with the formula {[YTbL(OH)(HO) (DMF)] ·1.5HO·DMF} (L = 3-amino-4-hydroxybenzoate) () has been synthesized and characterized by single crystal and powder X-ray diffraction, scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), inductively coupled plasma mass spectrometry (ICP-MS), electrophoretic mobility, and Fourier transform infrared (FTIR) spectroscopy. The structure presents two metal environments: a bioaugmented isosceles wedge (mm2) MO and a tricapped trigonal prism (-6m2) MNO.

Multifunctional Amino Acid Derivative Coordination Compounds: Novel Contrast Agent and Luminescence Materials.

In this work a family of multidimensional (2-(1H-tetrazol-5-yl)ethyl) amino acid coordination compounds have been synthesized and thoroughly characterized. For this purpose, glycine, valine, phenylalanine and tyrosine have been selected as starting amino acids and Mn, Zn and Cd as metallic nodes. From one side, for Mn based dimer magnetic resonance imaging studies have been conducted, prompted by the number and disposition of the coordinated water molecules and taking into consideration the promising future of manganese-based coordination compounds as bio-compatible substitutes to conventional Gd based contrast agents.

From field-induced to zero-field SMMs associated with open/closed structures of bis(ZnDy) tetranuclear complexes: a combined magnetic, theoretical and optical study.

We have prepared a bis(compartmental) Mannich base ligand HL (1,4,8,11-tetraaza-1,4,8,11-tetrakis(2-hydroxy-3-methoxy-5-methylbenzyl)cyclotetradecane) specifically designed to obtain bis(TMLn) tetranuclear complexes (TM = transition metal). In this regard, we have succeeded in obtaining three new complexes of the formula [Zn(μ-L)(μ-OAc)Dy(NO)]·[Zn(μ-L)(μ-OAc)Dy(NO)(OAc)]·4CHCl·2MeOH (1) and [TM(μ-HL)(μ-succinate)Ln(NO)] (NO)·2HO·6MeOH (TM = Zn, Ln = Dy (2); TM = Co, Ln = Dy (3)). Compound 1 contains two different bis(ZnDy) tetranuclear molecules that cocrystallize in the structure, in which acetato bridging ligands connect the Zn and Dy ions within each ZnDy subunit.

Nickel, copper, and zinc dinuclear helicates: how do bulky groups influence their architecture?

The ligand design factors that may influence the isolation of metallosupramolecular helicates or mesocates still deserve to be investigated. In this sense, dinuclear nickel(II), copper(II) and zinc(II) compounds were obtained by electrochemical synthesis using a family of five Schiff base ligands, HL ( = 1-5), derived from bisphenylmethane and functionalized with bulky -butyl groups in the periphery and ethyl groups in the spacer. Six of the new complexes were characterized by X-ray crystallography, thus demonstrating that the helicate structure is predominant in the solid state.

Zero-Field SMM Behavior Triggered by Magnetic Exchange Interactions and a Collinear Arrangement of Local Anisotropy Axes in a Linear Co Complex.

A new linear trinuclear Co(II) complex with a formula of [{Co(μ-L)}Co] has been prepared by self-assembly of Co(II) ions and the NO-tripodal Schiff base ligand HL, which is obtained from the condensation of 1,1,1-tris(aminomethyl)ethane and salicylaldehyde. Single X-ray diffraction shows that this compound is centrosymmetric with triple-phenolate bridging groups connecting neighboring Co(II) ions, leading to a paddle-wheel-like structure with a pseudo- axis lying in the Co-Co-Co direction. The Co(II) ions at both ends of the Co(II) molecule exhibit distorted trigonal prismatic CoNO geometry, whereas the Co(II) at the middle presents an elongated trigonal antiprismatic CoO geometry.

Formation of Irida-β-ketoimines and PCN-Ir(III) Complexes by Reacting Irida-β-diketones with Aliphatic Diamines: Catalytic Activity in Hydrogen Release by Methanolysis of HN-BH.

Aliphatic diamines [(HN(CH)NHR) () = 2: R = H (), R = CH (), R = CH (), = 3, R = H () or -2-(aminomethyl)piperidine ()] react with [IrH(Cl){(PPh(-CHCO))H}] in THF to afford ketoimine complexes [IrH(Cl){(PPh(-CHCO))(PPh(-CHCN(CH)NHR))H}] (-) or [IrH(Cl){(PPh(-CHCO))(PPh(-CHCNCH(CHNH)))H}] (), containing a bridging N-H···O hydrogen bond and a dangling amine. Complex consists of an almost equimolar mixture of two diastereomers. In protic solvents, the dangling amine in complexes displaces chloride to afford cationic acyl-iminium compounds, [IrH(PPh(-CHCO))(PPh(-CHCNH(CH)NHR))]X (-, X = Cl) or [IrH(PPh(-CHCO))(PPh(-CHCNHCH(CHNH)))]Cl () and (-, X = ClO), with new hemilabile terdentate PCN ligands adopting a facial disposition.

Slow Magnetic Relaxation and Modulated Photoluminescent Emission of Coordination Polymer Based on 3-Amino-4-hydroxybenzoate Zn and Co Metal Ions.

As a starting point, a new 3D porous framework with the {[CoL]·0.5DMF·HO} chemical formula (where L = 3-amino-4-hydroxybenzoate) is described. Its performance as a single molecule magnet was explored.

Easy Handling and Cost-Efficient Processing of a Tb-MOF: The Emissive Capacity of the Membrane-Immobilized Material, Water Vapour Adsorption and Proton Conductivity.

The development of convenient, non-complicated, and cost-efficient processing techniques for packing low-density MOF powders for industry implementation is essential nowadays. To increase MOFs' availability in industrial settings, we propose the synthesis of a novel 3D Tb-MOF () and a simple and non-expensive method for its immobilization in the form of pellets and membranes in polymethacrylate (PMMA) and polysulphone (PSF). The photoluminescent properties of the processed materials were investigated.

Influence of Tartrate Ligand Coordination over Luminescence Properties of Chiral Lanthanide-Based Metal-Organic Frameworks.

The present work reports on a detailed discussion about the synthesis, characterization, and luminescence properties of three pairs of enantiopure 3D metal-organic frameworks (MOFs) with general formula {[Ln(L/D-tart)(HO)]·3HO} (, where Ln = Sm(III), Eu(III) or Gd(III), and L/D-tart = L- or D-tartrate), and ten pairs of enantiopure 2D coordination polymers (CPs) with general formula [Ln(L/D-Htart)(OH)(HO)] (, where Ln = Y(III), Sm(III), Eu(III), Gd(III), Tb(III), Dy(III), Ho(III), Er(III), Tm(III) or Yb(III), and L/D-Htart = hydrogen L- or D-tartrate) based on single-crystal X-ray structures. Enantiopure nature of the samples has been further corroborated by Root Mean Square Deviation (RMSD) as well as by circular dichroism (CD) spectra. Solid-state emission spectra of Eu(III), Tb(III), and Dy(III)-based compounds confirm the occurrence of ligand-to-metal charge transfers in view of the characteristic emissions for these lanthanide ions, and emission decay curves were also recorded to estimate the emission lifetimes for the reported compounds.

Adsorptive Capacity, Inhibitory Activity and Processing Techniques for a Copper-MOF Based on the 3,4-Dihydroxybenzoate Ligand.

Due to the fast, emerging development of antibiotic-resistant bacteria, the need for novel, efficient routes to battle these pathogens is crucial; in this scenario, metal-organic frameworks (MOFs) are promising materials for combating them effectively. Herein, a novel Cu-MOF-namely -that displays the formula [CuL(DMF)] (DMF = ,-dimethylformamide) is described, synthesized by the combination of copper(II) and 3,4-dihydroxybenzoic acid (HL)-both having well-known antibacterial properties. The resulting three-dimensional structure motivated us to study the antibacterial activity, adsorptive capacity and processability of the MOF in the form of pellets and membranes as a proof-of-concept to evaluate its future application in devices.

Two Synthetic Approaches to Coinage Metal(I) Mesocates: Electrochemical versus Chemical Synthesis.

We report two different approaches to isolate neutral and cationic mesocate-type metallosupramolecular architectures derived from coinage monovalent ions. For this purpose, we use a thiocarbohydrazone ligand, HL (), conveniently tuned with bulky phosphine groups to stabilize the M ions and prevent ligand crossing to achieve the selective formation of mesocates. The neutral complexes [Cu(HL)] (), [Ag(HL)] (), and [Au(HL)] () were prepared by an electrochemical method, while the cationic complexes [Cu(HL)](PF) (), [Cu(HL)](BF) (), [Ag(HL)](PF) (), [Ag(HL)](NO) (), and [Au(HL)]Cl () were obtained by using a metal salt as the precursor.

Magneto-thermal properties and slow magnetic relaxation in Mn(II)Ln(III) complexes: influence of magnetic coupling on the magneto-caloric effect.

A family of Mn(II)Ln(III) dinuclear and tetranuclear complexes (Ln = Gd and Dy) has been prepared from the compartmental ligands ,'-dimethyl-,'-bis(2-hydroxy-3-formyl-5-bromobenzyl)ethylenediamine (HL) and ,',''-trimethyl-,''-bis(2-hydroxy-3-methoxy-5-methylbenzyl)diethylenetriamine (HL). The Mn(II)Gd(III) complexes exhibit antiferromagnetic interactions between Mn(II) and Gd(III) ions in most cases, which are supported by Density Functional Theory (DFT) calculations. Experimental magneto-structural correlations carried out for the reported complexes and other related complexes found in bibliography show that the highest ferromagnetic coupling constants are observed in di-μ-phenoxido bridged complexes, which is due to the planarity of the Mn-(μ-O)-Gd bridging fragment and to the high Mn-O-Gd angles.

Hydrolysis of a carbamate triggered by coordination of metal ions.

The mechanism of carbamate activation promoted by different metal ions has been explored in this work. The reaction of the carbamate ligand HL with chloride metal salts (M = Ni, Cu, Zn, Cd) leads to the coordination of the metal ions to the ligand, causing hydrolysis of the systems. This self-immolation process results in mononuclear dihydrazone complexes, carbon dioxide and the release of alcohol species from the pendant groups of the carbamate ligand.

Multifunctional Lanthanide-Based Metal-Organic Frameworks Derived from 3-Amino-4-hydroxybenzoate: Single-Molecule Magnet Behavior, Luminescent Properties for Thermometry, and CO Adsorptive Capacity.

Herein, we describe and study a new family of isostructural multifunctional metal-organic frameworks (MOFs) with the formula {[LnL(OH)(DMF)]·5HO} (where (HL) is 3-amino-4-hydroxybenzoic acid ligand) for magnetism and photoluminescence. Interestingly, three of the materials (Dy-, Er-, and Yb-based MOFs) present single-molecule magnet (SMM) behavior derived from the magnetic anisotropy of the lanthanide ions as a consequence of the adequate electronic distribution of the coordination environment. Additionally, photoluminescence properties of the ligand in combination with Eu and Tb counterparts were studied, including the heterometallic Eu-Tb mixed MOF that shows potential as ratiometric luminescent thermometers.

Slow Magnetic Relaxation and Luminescent Properties of Mononuclear Lanthanide-Substituted Keggin-Type Polyoxotungstates with Compartmental Organic Ligands.

The reaction of mid to late lanthanide ions with the ,'-dimethyl-,'-bis(2-hydroxy-3-formyl-5-bromobenzyl)ethylene-diamine organic ligand and monolacunary Keggin type [α-SiWO] anion affords a series of isostructural compounds, namely, K[Ln(α-SiWO)(CHBrNO)]·14HO (-Ln, Ln = Sm to Lu). The molecular structure of these sandwich-type complexes is formed by the Ln ion in a biaugmented trigonal prismatic geometry, which occupies the external O site of the organic ligand and the vacant site of the lacunary polyoxometalate (POM) unit. The empty NO coordination site of the organic ligand allows its unprecedented folding, which displays a relative perpendicular arrangement of aromatic groups.

A novel yttrium-based metal-organic framework for the efficient solvent-free catalytic synthesis of cyanohydrin silyl ethers.

A new porous metal-organic framework (MOF) with the chemical formula [YL(OH)(DMF)]·5HO (1) (where L = 3-amino-4-hydroxybenzoate) has been prepared by a solvothermal procedure. The structural characterization reveals that this material consists of a robust three-dimensional metal-organic framework (MOF) grown with clusters formed by Y(iii) and hydroxide anions joined to one another by the ligand, giving rise to an open structure with interconnected microchannels with variable dimensions. This assembled set has shown to possess a fascinating catalytic activity for the cyanosilylation of a broad range of aldehydes and ketones with exceptional recyclability, a solvent-free medium, and one order of magnitude lower catalyst loading compared to all related lanthanide-based MOFs described so far in the literature.

An Ideal Spin Filter: Long-Range, High-Spin Selectivity in Chiral Helicoidal 3-Dimensional Metal Organic Frameworks.

An enantiopure, conductive, and paramagnetic crystalline 3-D metal-organic framework (MOF), based on Dy(III) and the l-tartrate chiral ligand, is proved to behave as an almost ideal electron spin filtering material at room temperature, transmitting one spin component only, leading to a spin polarization (SP) power close to 100% in the ±2 V range, which is conserved over a long spatial range, larger than 1 μm in some cases. This impressive spin polarization capacity of this class of nanostructured materials is measured by means of magnetically polarized conductive atomic force microscopy and is attributed to the Chirality-Induced Spin Selectivity (CISS) effect of the material arising from a multidimensional helicity pattern, the inherited chirality of the organic motive, and the enhancing influence of Dy(III) ions on the CISS effect, with large spin-orbit coupling values. Our results represent the first example of a MOF-based and CISS-effect-mediated spin filtering material that shows a nearly perfect SP.

Modulating Magnetic and Photoluminescence Properties in 2-Aminonicotinate-Based Bifunctional Coordination Polymers by Merging 3d Metal Ions.

Herein, the synthesis and study of bifunctional coordination polymers (CPs) with both magnetic and photoluminescence properties, derived from a heterometallic environment, are reported. As a starting point, three isostructural monometallic CPs with the formula [M(μ-2ani) ] (M =Mn (1 ), Co (3 ) and Ni (4 ); 2ani=2-aminonicotinate), crystallise as chiral 2D-layered structures stacked by means of supramolecular interactions. These compounds show high thermal stability in the solid state (above 350 °C), despite which, in aqueous solution, compound 1 is shown to partially transform into a novel 1D chain CP with the formula [Mn(2ani) (μ-H O) ] (2 ).

Designing Single-Molecule Magnets as Drugs with Dual Anti-Inflammatory and Anti-Diabetic Effects.

We have designed and synthesized two novel cobalt coordination compounds using bumetanide (bum) and indomethacin (ind) therapeutic agents. The anti-inflammatory effects of cobalt metal complexes with ind and bum were assayed in lipopolysaccharide stimulated RAW 264.7 macrophages by inhibition of nitric oxide production.

A Potassium Metal-Organic Framework based on Perylene-3,4,9,10-tetracarboxylate as Sensing Layer for Humidity Actuators.

We have synthesized a novel three-dimensional metal-organic-framework (MOF) based on the perylene-3,4,9,10-tetracarboxylate linker and potassium as metallic centre. We report the formation of this K-based MOF using conventional routes with water as solvent. This material displays intense green photoluminescence at room temperature, and displays an aggregation dependent quenching.

Design and synthesis of a family of 1D-lanthanide-coordination polymers showing luminescence and slow relaxation of the magnetization.

We have designed and synthesized eight isostructural 1D coordination polymers (CPs) with the general formula {[Ln(aapc)3(DMF)]}n [where Ln(iii) = Y (2), La (3), Nd (4), Eu (5), Gd (6), Tb (7), Dy (8), Er (9); and aapc = 3-((anthraquinone-1-yl)amino)propanoate]. These CPs consist of Ln-carboxylate infinite rods in which the bulky anthraquinone scaffolds arise from it in such a way that the resulting supramolecular packing exhibits isolated 1D chains. Solution structures have been corroborated through NMR methods including PGSE and EXSY NMR studies and, due to the presence of lanthanide ions, magnetic and luminescence properties have been studied.