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Herein, we present the synthesis and structural characterisation of two layered MOFs with the asymmetric ligand 3-chloro,6-cyano-2,5-dihydroxy-1,4-benzoquinone dianion (C6O4(CN)Cl2− = chlorocyananilato). These compounds, formulated as (H3O)[Eu(C6O4(CN)Cl)2(H2O)]·34H2O (1) and (H3O)[Dy(C6O4(CN)Cl)2(H2O)]·44H2O (2), are isostructural and show a (4,4)-layered square structure with the crystallisation water molecules located between the layers. The lanthanoid ions are surrounded by four bis-bidentate chlorocyananilato ligands that connect each LnIII centre with other four, giving rise to square cavities formed by LnIII centres in the vertices and chlorocyananilato ligands as the sides. There is an additional coordinated water molecule that occupies the caped position of the capped square antiprismatic coordination geometry around the LnIII centres. The magnetic properties show the presence of a field-induced slow relaxation of the magnetisation in the DyIII derivative at low temperatures that follows Direct and Orbach relaxation mechanisms with an energy barrier of 36(3) K. [ABSTRACT FROM AUTHOR]

New manganese(II) and nickel(II) 1-D zigzag coordination polymers [M2+(pQ2−)·2(solv)]n (M2+ = Mn2+, solv = N,N'-dimethylacetamide (1) and M = Ni2+, solv = N,N'-dimethylformamide (2); pQ2− - dianionic form of 2,5-di-hydroxy-3,6-di-tert-butyl-para-quinone) have been synthesized and characterized. Both compounds 1 and 2 are isomorphic. Their physicochemical properties such as thermal stability, gas sorption, redox and magnetic properties are described. [ABSTRACT FROM AUTHOR]

In recent decades, the chemistry of transition metal coordination compounds has undergone continuous development at both scientific and application levels. The diversity of metal(II) complexes, along with their structural features and physicochemical properties, makes them attractive for a wide range of applications. The dicyanamide ion (N(CN)2) has the ability to form various transition metal compounds characterized by different architectures and topologies. The interaction of π-electrons from the nitrile groups with the π-system of the central nitrogen may enable electron delocalization, potentially facilitating electron transfer between the metal centers through the bridging dicyanamide (dca) ligand. This review focuses on dca–Co(II) compounds and, after a brief introduction, the structural aspects and magnetic properties are analyzed in detail. [ABSTRACT FROM AUTHOR]

The dinuclear oxidovanadium(IV/V) complex, [V2(HS2O8)O3(C18H24N2)2]⋅- CH3CN or [V2O2(μ-O)( μ-H(SO4)2)(4,4'-tBubpy)2]⋅CH3CN (4,40-tBubpy = 4,4'-di-tert-butyl-2,2'-bipyridine), has crystallographic C2 symmetry and exhibits a distorted octahedral geometry around the vanadium center, where the two 4,4'-tBubpy ligands are nearly orthogonal to each other. The two vanadium ions are linked by an oxo anion and a unique protonated sulfate anion [H(SO4)23-]. In the crystal, intermolecular C--H⋯π and π--π interactions between the 4,4'-tBubpy ligands are present, leading to a three-dimensional network. [ABSTRACT FROM AUTHOR]

Two-dimensional layered coordination polymers based on the hetero-substituted 3-chloro-6-cyano-2,5-dihydroxybenzoquinone ligands, hereafter ClCNAn2− anilate, and LnIII ions (Tb and Eu) are reported. Compounds 1 and 2, formulated as Ln2(ClCNAn)3(DMSO)6 (LnIII = Tb, 1; Eu, 2), and their related intermediates 1′ and 2′, formulated as Ln2(ClCNAn)3(H2O)x·yH2O (x + y likely = 12, Ln = Tb, 1′; and Eu, 2′), were prepared by a conventional one-pot reaction (the latter) and recrystallized from DMSO solvent (the former). Polyhydrated intermediates 1′ and 2′ show very similar XRPD patterns, while, despite their common stoichiometry, 1 and 2 are not isostructural. Compound 1 consists of a 2D coordination framework of 3,6 topology, where [Tb(DMSO)3]III moieties are bridged by three bis-chelating ClCNAn2− ligands, forming distorted hexagons. Ultrathin nanosheets of 1 were obtained by exfoliation via the liquid-assisted sonication method and characterized by atomic force microscopy, confirming the 2D nature of 1. The crystal structure of 2, still showing the presence of 2D sheets with a "hexagonal" mesh and a common (3,6) connectivity, is based onto flat, non-corrugated slabs. Indeed, at a larger scale, the different "rectangular tiles" show clear roofing in 1, which is totally absent in 2. The magnetic behavior of 1 very likely indicates depopulation of the highest crystal-field levels, as expected for TbIII compounds. [ABSTRACT FROM AUTHOR]

A new coordination polymer of coper (II), [tetra-azido)tris(2-pyridyl)amine)dicopper(II)] (1) has been synthesized by the reaction between copper(II) nitrate hexahydrate, sodium azide and tris(2-pyridyl)amine under solvothermal conditions in aqueous methanol. The structure has been characterized by single-crystal X-ray diffraction. An analysis of Hirschfeld surfaces was examined. Single-crystal results reveals that the structure contains two independent copper(II) centers, both having approximately square pyramidal coordination: in one, two of the basal sites are occupied by bidentate tris-(2-pyridyl)amine and two azido ligands, with a third azido ligand at the apical site, while the other center is coordinated only by azido ligands. All azido ligands bind two copper centers, forming a coordination polymer chain with two types of Cu2N2 rings and one type of Cu4N4 ring, and in which all azido ligands form a bridge between two metal centers in mode µ-1,1. The Hirshfeld analysis revealed an azido··· (pyridyl) interaction in the coordination polymer chain, as well as weak C-H···N interactions, one of which links the chains into sheets. A new dinuclear copper (II) polymer [tetra-azido(tris(2-pyridyl)amine)dicopper(II)] (1) has been synthesized under solvothermal conditions and been characterized by single-crystal X-ray diffraction and Hirshfeld surface analysis. [ABSTRACT FROM AUTHOR]

Two 1D coordination polymers were synthesized by reaction of two ligands, 2-amino-4-picoline (2A4Pic) and quinoline-6-carboxylic acid (Qu-6-COOH) with two metal (II) nitrate (M = Cd and Cu) in the presence of azide as a linker. The synthesized metal complexes [Cd(2A4Pic)2(N3)2]n; (1) and [Cu(Qu-6-COO)(N3)(H2O)]n; (2) were isolated in single crystals and their X-ray structures revealed a 1D polymeric structure. Due to symmetry considerations, the asymmetric formula is half a [Cd(2A4Pic)2(N3)2] unit for 1 and one [Cu(Qu-6-COO)(N3)(H2O)] unit for 2. In complex 1, the Cd(II) is hexa-coordinated with two 2A4Pic molecules and four μ(1,1) azide units. Hence, the CdN6 coordination environment has a slightly distorted octahedral geometry. In 2, the Cu(II) is hexa-coordinated with three different ligands (Qu-6-COO¯, H2O and μ(1,1) N3¯) where all are connectors between the crystallographically related Cu(II) sites. Additionally, complex 2 distorted CuN2O4 octahedral geometry. In both complexes, the polymer arrays are connected by N...H hydrogen bonds and π–π stacking interactions. Based on Hirshfeld analysis, the percentages of N...H contacts are 43.1 and 27.4% for 1 and 2, respectively, while %C...C are 5.6 and 9.3%, respectively. Analysis of Cu-N, Cu-O, and Cd-N bonds using DFT calculations showed predominantly closed-shell coordination interactions with little covalent characters. Additionally, the negatively charged ligand groups were found to compensate the positive charge of the central metal ion to a larger extent than the electrically neutral ligands. [ABSTRACT FROM AUTHOR]

A new 3D manganese(II) coordination polymer, formulated as [Mn3(HL)6] (1) (where H2L = 6-hydroxypicolinic acid), has been hydrothermally synthesized and characterized by single-crystal X-ray crystallographic analysis along with other spectroscopic and magnetic techniques. Structural analysis shows that the compound crystallizes in the monoclinic C2/c space group and is a non-porous 3D coordination polymer formed by three different Mn(II) centres connected by 6-hydroxypicolinic acid ligands in their keto form. Each Mn(II) centre shows a distorted octahedral coordination environment. Neighbouring Mn(II) centres are connected by two different syn-anti bridging carboxylate groups to form regular coordination chains. There are two different [Mn2(RCOO)2] units along the chain, formed by two crystallographically independent Mn centres (Mn1 and Mn2). These chains are further connected by HL− ligands to form a 3D coordination network. Interestingly, both the hydroxy and the carboxylate groups of the ligands are deprotonated and coordinated to the metal centres, whereas the pyridyl group is protonated and uncoordinated, although it participates in strong hydrogen bonding interactions with oxygen atoms of the HL− ligand, as shown by the Hirshfeld surface analysis. Both the absorption and emission spectra of the compound have also been measured. Variable temperature magnetic studies reveal the presence of a spin-canted antiferromagnetic behaviour with a high coercivity of 40 mT at 2 K and an ordering temperature of 14 K. [ABSTRACT FROM AUTHOR]

The coordination ability of the pyridine derivative of cyclic triimidazole, namely 3-(pyridin-2-yl)triimidazotriazine (TT-Py) towards Cu(I) was explored. TT-Py is an appealing nitrogen-rich ligand characterized by the presence of three imidazole nitrogen atoms with trigonal symmetry and a pyridine moiety, available for coordination to metal ions. The multidentate nature of TT-Py allows to isolate, by reaction with CuI at room temperature, the one-dimensional coordination network [Cu2I2(TT-Py)]n (1). 1 is characterized by a rare structural network built-up by the combination in a 1:2 ratio of two common motifs for Cu(I) halides coordination polymers, which are the double-stranded stair and the zig-zag chain. 1 displays one broad long-lived emission in the solid state, which has been associated, by the support of DFT and TDDFT calculation, with low-energy transitions of MLCT or XMLCT character. [ABSTRACT FROM AUTHOR]

Two new coordination polymers of cadmium-containing polynitrile ligands have been synthesized using sovothermal methods. In both poly[trans,trans,transbis(·-dicyanamido-κ²N¹:N³)bis(2-methylbenzimidazole-κN)cadmium(II)], [Cd(C2N3)2(C8H8N2)2]n, (I), and poly[trans,trans,trans-bis(2-methylbenzimidazole-κN)bis(·-tricyanomethanido-κ²N:N'cadmium(II)], [Cd(C4N3)2- (C8H8N2)2]n, (II), the Cd atom lies on a centre of inversion, in space groups P21/n and P21/c, respectively. In each polymer, each anionic ligand acts as a bridge between two metal centres, forming sheets of 24-membered rings, and in each structure a single N--H· · ·N hydrogen bond links the polymer sheets to form a three-dimensional framework structure. Comparisons are made with the structures of some related complexes. [ABSTRACT FROM AUTHOR]

Here, a new cyano-bridged 3d–4f compound, a Dy(III)–Fe(III) molecular assembly ([Dy(DMF)4(H2O)3(μ-CN)Fe(CN)5.H2O] (1)), having a structure consisting of neutral one-dimensional (1D) chains, as well as an unbound aqua molecule, was synthesized and characterized using single crystal X-ray diffraction (XRD), infrared (IR), and elemental analyses. We then examined its structural topologies and studied its density functional theory (DFT), Hirshfeld surface analyses, and photophysical properties. The 1D chains were further linked by H-bond interactions, generating a three-dimensional (3D) motif which stabilizes the whole molecule. The weak interactions in 1 were assessed using Hirshfeld surface analyses, as well as fingerprint plots and DFT studies. Additionally, Hirshfeld surface analysis was performed to elucidate the roles of the weak interactions, such as the H⋯H, C⋯H, C–H⋯π, and van der Waals (vdW) interactions which are pivotal to stabilizing the crystal environment. Furthermore, the DFT studies were used to elucidate the bonding structure within the complex system. Complex 1 exhibits characteristic fluorescence as the Dy(III) complex is an excellent lime green luminescent material. Thus, it is considered to be a suitable material for preparing photoluminescent material. [ABSTRACT FROM AUTHOR]

In addition to carboxylate and N-donor linkers, hydroxamates are a kind of new emerging ligand to form coordination polymers. However, owing to the difficulty in controlling the reversible formation of strong metal–hydroxamate coordination bonds, reports on ditopic or multitopic hydroxamate coordination polymers are rare. In this work, we combined the ligand H2ONDI, a bis-hydroxamate with a naphthalenediimide (NDI) core and rigid chelating groups, with transition metal ions (Mn2+ and Cd2+) and thus obtained three new hydroxamate coordination polymers. Benefiting from π–π stacking interactions between neighbouring ligands, Mn-ONDI-1 and CdCl-ONDI show interesting electrical conductivities. [ABSTRACT FROM AUTHOR]

Multicobalt(II) two-dimensional layer coordination polymer {[Co(bitbu-OMe)2(NCS)2]·2MeOH}n (1) was synthesized using a bis-imidazole ligand having a steric hindrance, tert-butyl, and one methoxy group expressed by bitbu-OMe (bitbu-OMe = 1,1′-[(5-tert-butyl-2-methoxybenzene-1,3-diyl)dimethanediyl]bis(1H-imidazole). Since there are two methanol molecules trapped inside each void within 1, the investigation of small organic matter removal from organic wastewater was conducted in order to reveal its ability in the purification process. The research findings indicate that 1 has the ability to capture methanol, acetone, acetonitrile, and tetrahydrofuran in organic wastewater with removal ratios of 29.17%, 63.22%, 42.77%, and 21.24%, respectively. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs), whose definition has been regularly debated, are a sub-class of coordination polymers (CPs) which may feature both an overall 3D architecture and some degree of porosity. In this context, MOFs based on lanthanides (Ln-MOFs) could find many applications due to the combination of sorption properties and magnetic/luminescent behaviors. Here we report rare examples of 3D Ln-CPs based on anilate linkers, obtained under solvothermal conditions using a heteroleptic strategy. The three compounds of formula [Yb2(μ-ClCNAn)2(μ-F4BDC)(H2O)4]·(H2O)3 (1), [Er2(μ-ClCNAn)2(μ-F4BDC)(H2O)4]·(H2O)4 (2) and [Eu2(μ-ClCNAn)2(μ-F4BDC)(H2O)6] (3) have been characterized by single-crystal X-ray diffraction, thermogravimetric analysis, and optical measurements. Structural characterization revealed that compounds 1 and 2 present an interesting MOF architecture with extended rectangular cavities which are only filled with water molecules. On the other hand, compound 3 shows a much more complex topology with no apparent cavities. We discuss here the origins of such differences and highlight the crucial role of the Ln(III) ion nature for the topology of the CP. Compounds 1 and 2 now offer a playground to investigate the possible synergy between gas/solvent sorption and magnetic/luminescent properties of Ln-MOFs. [ABSTRACT FROM AUTHOR]

The literature has witnessed the exceptionally rich coordination chemistry, ranging from monomeric species to coordination polymers, generated by the Schiff base ligands derived from o-vanillin. Plenty of purely 4f and mixed 3d–4f single-molecule magnets (SMMs) have been synthesized using these ligands aiming at their several futuristic applications ranging from data storage devices to the basic unit of quantum computers. In the present endeavour, we introduced for the first time a new methyl derivative of o-vanillin, 2-hydroxy-3-methoxy-5-methylbenzaldehyde (Me-val), to explore its coordination ability as well as the electronic effect of the methyl substitution at the para position with respect to the phenolic-OH group in the resulting complexes. Consequently, a Dy4 (1) and a Zn2Dy2 (2) complex have been synthesized and structurally characterized from a ligand, (E)-2-[(2-hydroxyphenyl)iminomethyl]-6-methoxy-4-methylphenol (H2L), derived from Schiff base condensation reaction of Me-val and o-aminophenol. Both complexes are butterfly-shaped structures with varied geometries around the Dy(III) ions, and in 2, the Zn(II) centres occupy the body positions and the Dy(III) ions are in the wing positions. Magnetic studies reveal that complex 1 displays slow magnetic relaxation at zero dc field, while complex 2 exhibits field supported slow magnetic relaxation. Ab initio calculations were further performed to understand the magnetic behaviours in these complexes, which revealed that the counter complementary effect of the ferromagnetic dipole–dipole interaction and the intramolecular antiferromagnetic interaction among the Dy centres overall describe the slow magnetic relaxation behaviours in these complexes. [ABSTRACT FROM AUTHOR]

The new host-guest ∞3[Cu2(CN)3HB] supramolecular coordination polymer (SCP1) where HB = imidazole cation, was synthesized and structurally elucidated by X-ray single crystal and elemental analyses as well as spectral investigations. The topology of SCP1 constructs of three-dimensional anionic {[Cu2(CN)3]-}∞ framework based on the mini-cycle [Cu2(μ3-CN)2] motifs with encapsulation of cationic imidazole ring. Nanoscale form (SCP1\) was obtained by ultrasonic irradiation and TEM image shows regular nanostructure with the particle size in the range of 19.25–24.35 nm. Luminescence behavior of SCP1 was investigated to detect its ability as sensor for selective determination of nitrobenzene and metal ions. SCP1 and 1\ were found to have high catalytic and photocatalytic activities for degradation of Indigo Carmine (IC) in presence of H2O2. Each catalyst was recycled without loss of catalytic efficiency. The effect of ultrasonic and UV-irradiation and the degradation mechanism were also investigated. [ABSTRACT FROM AUTHOR]

Two new coordination polymers [Dy3(PDA)4(HO)(H2O)2]·6H2O (1) H2[(H3O)Sm3(PDA)6]·14H2O (2) (H2PDA = 2,4-pyridinedicarboxylic acid), have been hydrothermally synthesized and characterized by elemental analysis, IR, TG, XRD as well as single-crystal X-ray diffraction. They display different three-dimensional coordination frameworks, in which 2,4-PDA exhibits μ4-(κ5N,O2:O2′:O4:O4′), μ4-(κ5N,O2:O2,O2′:O4:O4′) and μ1-(κ5N,O2) coordination modes. Their topological structures have been analyzed. It is interesting that they have the same topological structure. The luminescence properties of 1 and 2 were determined with solid samples. They show the exclusive luminescence emission of Dy(III) or Sm(III) ions, respectively. The magnetic properties of 1 were also studied. It displays antiferromagnetic Dy(III)···Dy(III) interactions. CCDC 1945187 and 1945188 for complexes 1 and 2, respectively. [ABSTRACT FROM AUTHOR]

• Delamination of 2D coordination polymers (2D-CPs). • Role of interstitial solvent molecules in the delamination of 2D-CPs. • Non-assisted delamination with solvents. • Bath versus tip sonication and their influence on the final flake formation. • Influence of the sonication time in the final delamination product. Two novel cadmium-based 2D coordination polymers have been synthesized and characterized. Experimental results evidence that the best delamination processes occurs when weak interactions dominate the cohesion between layers and solvent molecules are occluded within the crystalline network. In this case, the delamination of the crystals occurs spontaneously in water. On top of that, and thanks to the high stability of the resulting (flake) colloidal dispersions, we have completed a detailed study of the sonication assisted delamination impact by: I) comparison of two different sonication approaches (bath vs. tip sonication) and II) optimization of final flake morphology and yield by controlling solvent and sonication time. Our results definitely pave the way for the fabrication and implementation of 2D coordination polymers using ultrasound. [ABSTRACT FROM AUTHOR]

Abstract: Two‐dimensional (2D) metal‐organic layers (MOLs) are the 2D version of metal‐organic frameworks (MOFs) with nanometer thickness in one dimension. MOLs are also known as 2D‐MOFs, 2D coordination polymers, ultrathin MOF nanosheets (UMOFNs) or coordination nanosheets in literature. This new category of 2D materials has attracted a lot of interests because of the opportunity in combining molecular chemistry, surface/interface chemistry and material chemistry of low dimensional materials in these systems. Several synthetic strategies have been developed for the construction of 2D MOLs, but the general synthesis of MOLs still presents a challenge. This tutorial level review summarizes the recent progress in the fabrication of novel 2D MOLs and aims to highlight challenges in this field. [ABSTRACT FROM AUTHOR]

A new compound, [{Cu'(bim)}4{SiW12O40}] (1) (bim= l,2-bis(imidazol-l'-yl)ethane), was hydro-thermally synthesized and characterized by elemental analyses, IR, TG, and single-crystal X-ray diffraction. Compound 1 is an infinite 1-D chain composed of Cu-bim coordination polymers and [0C-SÍW12O40]4- polyanions. The electrochemical and electrocatalytic behaviors of l-modified car-bon paste electrode (1-CPE) have been studied. [ABSTRACT FROM AUTHOR]

Two new cadmium(II) complexes [Cd1.5(L)Cl2(H2O)]2n(1) and [CdL2]n(2) with a multidentate N-donor building block 3-(pyridin-4-yl)-5-(pyrazin-2-yl)-1H-1,2,4-triazole (HL) have been prepared and characterized by elemental analysis, infra-red spectra, powder X-ray diffraction (XRD), and single-crystal XRD.1is a 2-D layered coordination polymer constructed from linkage of [Cd3(μ-Cl)4] trinuclear units with HL spacers, while2shows a 2-D layer structure. 3-D supramolecular architectures are further assembled in1and2viahydrogen-bonding contacts. Both1and2are thermally stable to 450 °C, and2showed strong fluorescent emission bands. [ABSTRACT FROM AUTHOR]

A one-dimensional cross-like chain coordination polymer, {[Zn2(4,4'-bipy)2(SO4)3(H2O)5][Zn(H2O)6]}n (1) (4,4'-bipy = 4,4'-bipyridine), has been prepared and characterized by infrared (IR) spectroscopy, elemental analysis, and single-crystal x-ray diffraction. The fluorescence properties of the polymer have also been determined. [ABSTRACT FROM AUTHOR]

We report a new structure of {[Co(bpy)2(ox)][{Cu2(bpy)2(ox)}Fe(ox)3]}n·8.5nH2O NCU-1 presenting a rare ladder topology among oxalate-based coordination polymers with anionic chains composed of alternately arranged [Cu2(bpy)2(ox)]2+ and [Fe(ox)3]3− moieties. Along the a axis, they are separated by Co(III) units to give porous material with voids of 963.7 Å3 (16.9% of cell volume). The stability of this structure is assured by a network of stacking interactions and charge-assisted C-H...O hydrogen bonds formed between adjacent chains, adjacent cobalt(III) units, and alternately arranged cobalt(III) and chain motifs. The soaking experiment with acetonitrile and bromobenzene showed that water molecules (8.5 water molecules dispersed over 15 positions) are bonded tightly, despite partial occupancy. Water adsorption experiments are described by a D'arcy and Watt model being the sum of Langmuir and Dubinin–Serpinski isotherms. The amount of primary adsorption sites calculated from this model is equal 8.2 mol H2O/mol, being very close to the value obtained from the XRD experiments and indicates that water was adsorbed mainly on the primary sites. The antiferromagnetic properties could be only approximately described with the simple CuII-ox-CuII dimer using H = −J·S1·S2, thus, considering non-trivial topology of the whole Cu-Fe chain, we developed our own general approach, based on the semiclassical model (SC) and molecular field (MF) model, to describe precisely the magnetic superexchange interactions in NCU-1. We established that Cu(II)-Cu(II) coupling dominates over multiple Cu(II)-Fe(III) interactions, with JCuCu = −275(29) and JCuFe = −3.8(1.6) cm−1 and discussed the obtained values against the literature data. [ABSTRACT FROM AUTHOR]

We present the magnetic properties of the metal-organic framework {[CoCxAPy]·2.15 H2O}n (Cx = bis(carboxypropyl)tetramethyldisiloxane; APy = 4,4′-azopyridine) (1) that builds up from the stacking of 2D coordination polymers. The 2D-coordination polymer in the bc plane is formed by the adjacent bonding of [CoCxAPy] 1D two-leg ladders with Co dimer rungs, running parallel to the c-axis. The crystal packing of 2D layers shows the presence of infinite channels running along the c crystallographic axis, which accommodate the disordered solvate molecules. The Co(II) is six-coordinated in a distorted octahedral geometry, where the equatorial plane is occupied by four carboxylate oxygen atoms. Two nitrogen atoms from APy ligands are coordinated in apical positions. The single-ion magnetic anisotropy has been determined by low temperature EPR and magnetization measurements on an isostructural compound {[Zn0.8Co0.2CxAPy]·1.5 CH3OH}n (2). The results show that the Co(II) ion has orthorhombic anisotropy with the hard-axis direction in the C2V main axis, lying the easy axis in the distorted octahedron equatorial plane, as predicted by the ab initio calculations of the g-tensor. Magnetic and heat capacity properties at very low temperatures are rationalized within a S* = 1/2 magnetic dimer model with anisotropic antiferromagnetic interaction. The magnetic dimer exhibits slow relaxation of the magnetization (SMM) below 6 K in applied field, with a τlf ≈ 2 s direct process at low frequencies, and an Orbach process at higher frequencies with U/kB = 6.7 ± 0.5 K. This compound represents a singular SMM MOF built-up of Co-dimers with an anisotropic exchange interaction. [ABSTRACT FROM AUTHOR]

Three new 3D metal–organic frameworks of lanthanum based on mixed anionic ligands, [(La2(pQ)2(BDC)4)·4DMF]n, [(La2(pQ)2(DHBDC)4)·4DMF]n, [(La2(CA)2(BDC)4)·4DMF]n (pQ—dianion of 2,5-dihydroxy-3,6-di-tert-butyl-para-quinone, CA—dianion of chloranilic acid, BDC-1,4-benzenedicarboxylate, DHBDC-2,5-dihydroxy-1,4-benzenedicarboxylate and DMF-N,N′-dimethylformamide), were synthesized using solvothermal methodology. Coordination polymers demonstrate the rare xah or 4,6T187 topology of a 3D framework. The homoleptic 2D-coordination polymer [(La2(pQ)3)·4DMF]n was obtained as a by-product in the course of synthetic procedure optimization. The thermal stability, spectral characteristics and porosity of coordination polymers were investigated. [ABSTRACT FROM AUTHOR]

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 literature. [ABSTRACT FROM AUTHOR]

Herein is presented the preparation and characterization of a composite material obtained by the combination of nanosheets of a coordination polymer (CP) based on the copper(I)-I double chain with response to temperature and pressure with polylactic acid (PLA) as biodegradable organic matrix. The new films of composite materials are generated using a simple and low-cost method and can be created with long lateral dimensions and thicknesses ranging from a few microns to a few nanometers. Studies show that the new material maintains the optical response versus the temperature, while the elasticity and flexibility of the PLA totally quenches the response to pressure previously observed for the CP. This new material can act as a reversible sensor at low temperatures, thanks to the flexibility of the copper(I)-iodine chain that conforms the CP. The addition of CP to the PLA matrix reduces the elastic modulus and ultimate elongation of the organic matrix, although it does not reduce its tensile strength. [ABSTRACT FROM AUTHOR]

The structures of three tetramethylammonium cyanocuprate(I) 3D networks [NMe4]2[Cu(CN)2]2•0.25H2O (1), [NMe4][Cu3(CN)4] (2), and [NMe4][Cu2(CN)3] (3), (Me4N = tetramethylammonium), and the photophysics of 1 and 2 are reported. These complexes are prepared by combining aqueous solutions of the simple salts tetramethylammonium chloride and potassium dicyanocuprate. Single-crystal X-ray diffraction analysis of complex 1 reveals {Cu2(CN)2(μ2-CN)4} rhomboids crosslinked by cyano ligands and D3h {Cu(CN)3} metal clusters into a 3D coordination polymer, while 2 features independent 2D layers of fused hexagonal {Cu8(CN)8} rings where two Cu(I) centers reside in a linear C∞v coordination sphere. Metallophilic interactions are observed in 1 as close Cu⋯Cu distances, but are noticeably absent in 2. Complex 3 is a simple honeycomb sheet composed of trigonal planar Cu(I) centers with no Cu...Cu interactions. Temperature and time-dependent luminescence of 1 and 2 have been performed between 298 K and 78 K and demonstrate that 1 is a dual singlet/triplet emitter at low temperatures while 2 is a triplet-only emitter. DFT and TD-DFT calculations were used to help interpret the experimental findings. Optical memory experiments show that 1 and 2 are both optical memory active. These complexes undergo a reduction of emission intensity upon laser irradiation at 255 nm although this loss is much faster in 2. The loss of emission intensity is reversible in both cases by applying heat to the sample. We propose a light-induced electron transfer mechanism for the optical memory behavior observed. [ABSTRACT FROM AUTHOR]