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A new porous metal–organic framework (MOF) with the chemical formula [Y5L6(OH)3(DMF)3]·5H2O (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.

Tetravanadate [V4O12]4− anion, one of the cyclic polyoxovanadates formed by the condensation of VO4 units, was used as the bidentate bridging ligand to design bimetallic materials from its functionalization with copper(II) complexes based on α-amino acids and typical aromatic ligands. The complexes {[Cu(Orn)(phen)]2[μ2-V4O12]}·6H2O (1), {[Cu(Lys)(bipy)]4[μ2-V4O12]·14H2O}n (2) and {[Cu(Gly)(phen)]2[μ2-V4O12]} [Cu(Gly)(phen)(H2O)]2·10H2O (3) (Orn = ornithine, phen = 1,10-phenanthroline, Lys = lysine, bipy = 2,2′-bipyridine, Gly = glycine) were prepared under non-hydrothermal conditions. These compounds were obtained at basic pH values (close to 9), which facilitated the formation of tetravanadate anion (from the precursor NH4VO3) and its stabilization with the metal complexes. All compounds crystallized in the triclinic system and showed an interesting structural and magnetic diversity, despite the fact that the components that form them are very similar. Although in compounds 1 and 3 the copper atoms are separated by the inorganic [V4O12]4− anion by about 10 A, the magnetic properties suggest antiferromagnetic interactions, which are explained through the intermolecular Cu⋯Cu interactions and the magnetic exchange pathways between the COO− groups and the magnetic centres. The most striking feature of compound 2 was the formation of a 1D polymeric chain constructed with [V4O12]4− units separated by [Cu(Lys)(bipy]24+ dinuclear bridges. The intramolecular Cu⋯Cu separation in this compound was 5.2 A, and the magnetic properties suggest a canted antiferromagnetic ordering at low applied magnetic fields.

Despite some limitations such as long-term side effects or the potential presence of intrinsic or acquired resistance, platinum compounds are key therapeutic components for the treatment of several solid tumors. To overcome these limitations, maintaining the same efficacy, organometallic ruthenium(II) compounds have been proposed as a viable alternative to platinum agents as they have a more favorable toxicity profile and represent an ideal template for both, high-throughput and rational drug design. To support the preclinical development of bis-phoshino-amine ruthenium compounds in the treatment of breast cancer, we carried out chemical modifications in the structure of these derivatives with the aim of designing less toxic and more efficient therapeutic agents. We report new bis-phoshino-amine ligands and the synthesis of their ruthenium counterparts. The novel ligands and compounds were fully characterized, water stability analyzed, and their in vitro cytotoxicity against a panel of tumor cell lines representative of different breast cancer subtypes was evaluated. The mechanism of action of the lead compound of the series was explored. In vivo toxicity was also assessed. The results obtained in this article might pave the way for the clinical development of these compounds in breast cancer therapy., We gratefully acknowledge the financial support from the Ministerio de Ciencia e Innovación y Agencia Estatal de la Investigación, Spain (Grant Nos. PID2020-117788RB-I00, PID2020-113661GB-I00, CTQ2017-84131-R and RED2018-102387-T Programa Redes Consolider), and Instituto de Salud Carlos III grant number PI16/01121. Alberto Ocaña’s lab is supported by the Instituto de Salud Carlos III (ISCIII, PI19/00808); CRIS Cancer Foundation, ACEPAIN, and Diputación de Albacete.

Helical aluminium complexes [Al2X4(μ-nbptam)] (X = Me 1, Et 2), [Al2X4(μ-fbpam)] (R = Me 3, Et 4), [Al3X7(μ-nbptam)] (X = Me 5, Et 6) and [Al3X7(μ-fbpam)] (X = Me 7, Et 8) have been prepared by treatment of scorpionate ligand precursors with two or three equivalents of the corresponding trialkylaluminium derivative. The structures of these complexes have been determined by spectroscopic methods and the X-ray crystal structure of complex 1 has also been established. These complexes have been studied as catalysts for the chemical fixation of carbon dioxide into cyclic carbonates displaying good catalytic activity. When cyclohexene oxide was used as a substrate, polyether-polycarbonate was obtained in a ratio which is highly dependent on the cocatalyst and the catalyst to cocatalyst ratio used.

The reaction of [RhCl(COD)]2 (COD = 1,5-cyclooctadiene) with racemic PPh2(CH(Ph)CH2CHO) and pyridine (py) led to the oxidative addition of the aldehyde, and a single geometric isomer of [RhHCl(PPh2(CH(Ph)CH2CO))(py)2] (1), with hydride trans to chloride, was obtained as a mixture of two diastereomers in a 95 : 5 ratio; this was in agreement with density functional theory (DFT) calculations. In a chloroform solution, the exchange of hydride by chloride yielded [RhCl2(PPh2(CH(Ph)CH2CO))(py)2] (2) as a mixture of a kinetically preferred species, trans-py-2a, and two diastereomers, cis-Cl-2b' and cis-Cl-2b, with cis pyridines and a chloride trans to acyl; as predicted by the DFT calculations, the latter was the major species. Complex 1 reacted with racemic PPh2(CH(Ph)CH2CHO) or PPh2(o-C6H4CHO) to afford [RhHCl(PPh2(CH(Ph)CH2CO))(κ1-PPh2(CH(Ph)CH2CHO))(py)] (3) or [RhHCl(PPh2(o-C6H4CO))(κ1-PPh2(CH(Ph)CH2CHO))(py)] (4), respectively, both with a dangling alkylaldehyde. Diastereomeric mixtures with the ratios 3a/3a' = 80 : 20 and 4a/4a' = 50 : 50 were obtained. Complex 4 reacted with N-donors to afford cationic [RhH(NN)(PPh2(o-C6H4CO))(κ1-PPh2(CH(Ph)CH2CHO))]BPh4 (NN = 1,10-phenanthroline, 5; 2,2'-bipyridine, 6) or with 8-aminoquinoline (aqui) or 2-(aminomethyl)pyridine to yield imination products with terdentate ligands: [RhH(PPh2(o-C6H4CO))(κ3-PNN)]BF4 (PNN = PPh2(CH(Ph)CH2CNC9H6N), 7 and PPh2(CH(Ph)CH2CNCH2C5H4N), 8, respectively. Compounds 5-8 were obtained as equimolar a/a' mixtures of diastereomers. Moreover, 5a and 5a' could be separated. [RhCl(NBD)]2 reacted with racemic PPh2(CH(Ph)CH2CHO) and N-donors to provide nortricyclyl (Ntyl) derivatives [RhCl(NN)(Ntyl)(PPh2CH(Ph)CH2CO)] (NN = phen, 9 and bipy, 10) as an a/a' = 75 : 25 mixture of diastereomers. By reacting [RhCl(NBD)]2 with PPh2(CH(Ph)CH2CHO) and quinoline-8-carbaldehyde in methanol, the phosphino-ester complex [RhCl(Ntyl)(C9H6NCO)(κ2-PPh2CH(Ph)CH2CO(OCH3)] 11 was obtained. The initial equimolar mixture of two diastereomers readily transformed into a single diastereomer, which was found to be thermodynamically most stable by the DFT calculations. Furthermore, single crystal X-ray diffraction analysis of cis-Cl-2b, 5a, 7a, 10a and 11 is reported.

The first phosphine-stabilized cationic rhodium silylene complex is reported. A dihydrido-silylene-Rh(iii) compound reacts with water and alcohols forming alkoxysilyl-Rh(iii) complexes and hydrogen gas. Moreover, benzophenone reacts with a cationic silylene rhodium complex leading to the reduction of the carbonyl group and the formation of an alkoxysilyl-Rh(iii) compound which has been identified as a likely intermediate in the mechanism for the hydrosilylation of ketones proposed by Hofmann and Gade.

A new coordination mode for the hybrid scorpionate/cyclopentadienyl ligand bpzcp, [bpzcp = 2,2-bis(3,5-dimethylpyrazol-1-yl)-1,1-diphenylethylcyclopentadienyl] is observed in iridium complexes. The reaction of the lithium precursor, [Li(bpzcp)(THF)], with a range of [IrCl(diene)]

This work was supported by FONDECYT, Project No. 1200748. Y.R.Y. acknowledges funding from Pontificia Universidad Catolica de Chile via a VRI 2015 -2017 fellowship and Ph.D. CONICYT 2018 fellowship No. 21182120. A.M.-S. acknowledges funding from Ph.D. CONICYT fellowship No. 51150322. The authors also gratefully acknowledge financial support from the Ministerio de Ciencia e Innovacion, Spain (grant numbers CTQ2016-77614-P and RED2018-102387-T) and "Plan Propio de I + D + i" of the Universidad Castilla-La Mancha (grant number 2020-GRIN29078)., A set of trisubstituted guanidine ligands L1H2-L4H2 with general formula (PrHN)(2)CNR (R = Ph (L1H2), R = 2,4,6-Me3C6H2(L2H2), R = p-BrC6H4(L3H2), R = (C5H4)Fe(C5H5), Fc (L4H2)) was employed to synthesize a family of mono- and dinuclear asymmetric methyl aluminum guanidinato compounds ((L2H)AlMe2 (1), (L4H)AlMe2 (2), (L-1)Al2Me4 (3), (L-2)Al2Me4 (4), (L-3)Al2Me4 (5), (L-4)Al2Me4 (6), (L1H)(2)AlMe (7), (L2H)(2)AlMe (8), and (L4H)(2)AlMe (9)) that were characterized by NMR spectroscopy (1-9) and single-crystal X-ray diffraction (4 and 8). These compounds were tested as catalysts for the fixation of carbon dioxide with epoxides to give cyclic carbonates, using tetrabutylammonium iodide (TBAI) as cocatalyst. The reactions were performed under solvent-free conditions at 70 degrees C and 1 bar CO2 pressure. Complexes 1-9 were more active than their respective free guanidines under the same experimental conditions for the synthesis of styrene carbonate (11a). The dinuclear complex 6 was the most efficient and active catalyst for the synthesis of several monosubstituted carbonates (11a-1) with excellent conversions and selectivities. Furthermore, the formation of some disubstituted cyclic carbonates (13a-c) using this dinuclear aluminum catalyst was also studied., Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT) CONICYT FONDECYT 1200748, Pontificia Universidad Catolica de Chile, Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT) 51150322 21182120, Spanish Government CTQ2016-77614-P RED2018-102387-T, "Plan Propio de I + D + i" of the Universidad Castilla-La Mancha 2020-GRIN29078

Herein, we report the magnetic and photoluminescence characterization of coordination polymers (CP) built from the combination of lanthanide(III) ions, pyrimidine-4,6-dicarboxylate (pmdc) ligand and a co-ligand with formula {[Dy(&mu, pmdc)(&mu, ox)0.5(H2O)3]&middot, 2H2O}n (1-Dy), {[Dy(&mu, 3-pmdc)(&mu, ox)0.5(H2O)2] ~2.33H2O}n (2-Dy), {[Dy2(&mu, 4-pmdc)(&mu, ox)(H2O)3]&middot, 5H2O}n (3-Dy), {[Ln(&mu, ox)0.5(H2O)2]&middot, H2O}n (where Ln(III) = Nd (4-Nd), Sm (4-Sm), Eu (4-Eu) and Dy (4-Dy)) and {[Dy(&mu, 4-pmdc)(NO3)(H2O)]&middot, H2O}n (5-Dy). It must be noted the presence of oxalate anion acting as ditopic co-ligand in compounds 1-Dy, 2-Dy, 3-Dy and 4-Ln, whereas in 5-Dy the nitrate anion plays the role of terminal co-ligand. Direct current measurements carried out for the dysprosium-based CPs reveal almost negligible interactions between Dy3+ ions within the crystal structure, which is confirmed by computed values of the exchange parameters J. In addition, alternating current measurements show field-induced single-molecule magnet (SMM) behavior in compounds 1-Dy, 2-Dy, 4-Dy and 5-Dy, whereas slight-frequency dependence is also observed in 3-Dy. Solid state emission spectra performed at room temperature for those compounds emitting in visible region confirm the occurrence of significant ligand-to-lanthanide charge transfer in view of the strong characteristic emissions for all lanthanide ions. Emission decay curves were also recorded to estimate the emission lifetimes for the reported compounds, in addition to the absolute quantum yields. Among them, the high quantum yield of 25.0% measured for 4-Eu is to be highlighted as a representative example of the good emissive properties of the materials.

This work reports on the preparation and optical characterization of two metal-organic frameworks (MOFs) based on strontium ions and 2-amino-1,4-benzenedicarboxylate (NH2-bdc) ligand: i.e., [Sr(NH2-bdc)(DMF)]n (1) and {[Sr(NH2-bdc)(Form)]·H2O}n (2) (where DMF = dimethylformamide and Form = formamide). Compound 1 has a 3D architecture built up from the linkage established by NH2-bdc among metal-carboxylate rods, leaving significant microchannels that are largely occupied by DMF molecules coordinated to strontium centers. The solvent molecules play a crucial role in the photoluminescence (PL) properties, which has been deeply characterized by diffuse reflectance and variable-temperature emission. Interestingly, both materials present intriguing photoluminescence (PL) properties involving intense short-lived and long-lasting phosphorescence (LLP), though the latter is especially remarkable for compound 2 with a lifetime of 815 ms at low temperature. Conversely, the strong PL shown by 1 may be successfully exploited due to both its luminescent thermochromism observed in the RT to 10 K range and its solvent-dependent PL sensing capacity, imbuing this material with potential activity as a PL thermometer as well as a toluene detector in water solutions.

Five new coordination polymers (CPs) constructed of aminopyridine-2-carboxylate (ampy) ligand have been synthesized and fully characterized. Three of them correspond to metal-organic chains built from the coordination of ampy to sodium and lanthanides with formulae [MNa(ampy)4]n (M = terbium (2), erbium (1) and ytterbium (3)) resembling a previously reported dysprosium material which shows anticancer activity. On another level, the reaction of Hampy with cobalt and copper ions ({[CoK(ampy)3(H2O)3](H2O)3}n (4) and [Cu(ampy)2]n (5)) lead to CPs with variable dimensionalities, which gives the opportunity of analyzing the structural properties of this new family. Lanthanide materials display solid state intense photoluminescent emissions in both the visible and near-infrared region and exhibit slow relaxation of magnetization with frequency dependence of the out-of-phase susceptibility. More interestingly, in our search for multifunctional materials, we have carried out antitumor measurements of these compounds. These multidisciplinary studies of metal complexes open up the possibility for further exploring the applications in the fields of metal-based drugs., This work has been funded by Red Guipuzcoana de Ciencia, Tecnología e Innovación (OF188/2017), University of the Basque Country (GIU 17/13), Gobierno Vasco/Eusko Jaurlaritza (IT1005-16), Junta de Andalucía (FQM-1484 and FQM-394) and the Spanish Ministry of Economy and Competitiveness (MCIU/AEI/FEDER, UE) (PGC2018-102052-A-C22, PGC2018-102052-B-C21). The authors thank for technical and human support provided by SGIker of UPV/EHU and European funding (ERDF and ESF).

Herein, we present, for the first time, a 2D-MOF based on copper and 4-hydroxypyrimidine-5-carbonitrile as the linker. Each MOF layer is perfectly flat and neutral, as is the case for graphene. High pressure X-ray diffraction measurements reveal that this layered structure can be modulated between 3.01 to 2.78 Å interlayer separation, with an evident piezochromism and varying conductive properties. An analysis of the band structure indicates that this material is conductive along different directions depending on the application of pressure or H doping. These results pave the way for the development of novel layered materials with tunable and efficient properties for pressure-based sensors., European Union (EU) 604391, Swiss National Science Foundation (SNSF) 200020_162861, Spanish Government CEX2018-000805-M CTQ2015-69163-CO2R1 PGC2018-102052-B-C21 PGC2018-102052-A-C22 PGC2018102047-B-I00 FIS2016-80434-P PID2019-109539GB-C43, Junta de Andalucia FQM-394, Comunidad Autonoma de Madrid through the Nanomag COST-CM Program S2018/NMT-4321, University of Seville, National Council for Scientific and Technological Development (CNPq) 405107/2017-0

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. Firstly, we determined the cytotoxicity and the anti-inflammatory potential of the cobalt compounds and ind and bum ligands in RAW 264.7 cells. Indomethacin-based metal complex was able to inhibit the NO production up to 35% in a concentration-dependent manner without showing cytotoxicity, showing around 6–37 times more effective than indomethacin. Cell cycle analysis showed that the inhibition of NO production was accompanied by a reversion of the differentiation processes in LPS-stimulated RAW 264.7 cells, due to a decreased of cell percentage in G0/G1 phase, with the corresponding increase in the number of cells in S phase. These two materials have mononuclear structures and show slow relaxation of magnetization. Moreover, both compounds show anti-diabetic activity with low in vitro cell toxicities. The formation of metal complexes with bioactive ligands is a new and promising strategy to find new compounds with high and enhanced biochemical properties and promises to be a field of great interest., This work has been funded by Junta de Andalucía (FQM-394 and FQM-1484), the Spanish Ministry of Economy and Competitiveness (MCIU/AEI/FEDER, UE) (PGC2018-102052-A-C22, PGC2018-102052-B-C21, and PGC2018-102047-B-I00) and Red Guipuzcoana de Ciencia, Tecnología e Innovación (OF188/2017), University of the Basque Country (GIU 17/13). The authors thank for technical and human support provided by SGIker of UPV/EHU and European funding (ERDF and ESF).

We report the formation of five novel multifunctional coordination polymers based on 1H-indazole-4- carboxylic acid (HL). To the best of our knowledge, these complexes are the first examples of coordination compounds constructed with this interesting ligand. These materials were synthesized by solvothermal routes, possess different 2D-structures and show interesting magnetic properties due to the copper compound showing an unusual spin-canted effect while the anisotropic cobalt material behaves as a fieldinduced single molecule magnet. MTT assays performed on human embryonic kidney (HEK293) and mouse skin melanoma (B16-F10) cell lines indicated that the Cd-based compound was the only one exhibiting dose-dependent toxicity on B16-F10 cells, most likely due to the release of toxic Cd(II). Cadmium and zinc polymers exhibit interesting luminescence properties. The fact that zinc polymers did not exhibit inherent toxicity against both cancer and non-cancerous cells make this new family an excellent candidate for further investigation in the field of luminescent materials with biomedical applications., Junta de Andalucia FQM-394 FQM-1484, Red Guipuzcoana de Ciencia, Tecnologia e Innovacion OF218/2018, University of Basque Country GIU 17/13, Basque Government IT1005-16, Spanish Ministry of Science, Innovation and Universities (MCIU/AEI/FEDER, UE) PGC2018-102052-A-C22 PGC2018-102052-B-C21, European Union (EU), ESF, Government of the Basque Country, FEDER/MCIU/AEI RYC-2016-21042 JdC-2017

A selective three-component coupling was employed to fix carbon dioxide to boron guanidinato compounds. The one-pot reaction of carbon dioxide, carbodiimides, and borylamines (ArNH)BC8H14 afforded the corresponding 1,2-adducts {R(H)N}C{N(Ar)}(NR)(CO2)BC8H14. Alternatively, the reaction with p-MeOC6H4NC or 2,6-Me2C6H3NC gave the corresponding isocyanide 1,1-adducts {i-PrHN}C{N(p-Me-C6H4)}(Ni-Pr){CNAr}BC8H14. The molecular structures of products (2,6-i-Pr2C6H3NH)BC8H14 7, {i-Pr(H)N}C{N(p-MeC6H4)}(Ni-Pr)(CO2)BC8H14 9, {Cy(H)N}C{N(p-MeC6H4)}(Cy)(CO2)BC8H14 13, and {i-PrHN}C{N(p-MeC6H4)}(Ni-Pr){CNR″}BC8H14 (R″ = p-MeOC6H4, 2,6-Me2C6H3) 14 and 15 were established by X-ray diffraction. Density functional theory calculations at the M05-2X level of theory revealed that CO2 fixation and formation of the corresponding adduct is exothermic and proceeds via a nonchelate boron guanidinato intermediate.

Two triazolopyrimidine complexes have been obtained from reaction between 7-amino-1,2,4-triazolo[1,5-a]pyrimidine (7atp) and Cu (II) salts. Crystal structures of [Cu2(μ-7atp)4Cl2]Cl2·4H2O (1) and [Cu2(μ-7atp)4(H2O)2](NO3)4·H2O (2) have been studied by X-ray diffraction methods and characterized by spectroscopic and thermal analysis. Magnetic studies of these dinuclear complexes have revealed the existence of moderate antiferromagnetic interactions between the copper ions, with J values of -91.2 and -96.1cm-1 respectively. It must be highlighted that the antiparasitic activity of these new complexes has been studied in vitro against three different strains of leishmania spp. and Trypanosoma cruzi, showing a higher efficacy than the 7atp ligand and the reference commercial drugs.

Two novel coordination polymers (CPs) based on zinc(II) and acyclic dicarboxylate linkers, i.e. [Zn2(μ3-IA)2(H2O)4]n (1-W) and {[Zn2(μ-IA)2(DMF)]·H2O}n (2-DMF) (where IA2− = itaconate) have been obtained as a result of a systematic study of some synthetic factors such as pH and solvents, which has allowed optimizing the conditions that render the best yields. 1-W is obtained as X-ray quality single crystals upon which diffraction analysis has been conducted, showing that it consists of a neutral 2D layered structure. Some structural details have been elucidated for 2-DMF based on a comparison of PXRD data with 1-W and in view of the similar composition of both crystalline phases. Photoluminescence (PL) measurements confirm that 2-DMF presents slightly different spectra from those of 1-W. Time-dependent density functional theory (TD-DFT) calculations of 1-W reveal that electronic transitions arise from both first excited singlet and triplet states involving ligand-centred emissions. Moreover, both compounds exhibit blue fluorescence and green phosphorescence that involves less frequent long-lasting phosphorescence (LLP) at 10 K. Exhaustive characterization of long-lasting phosphorescence by means of time-resolved spectroscopy reveals remarkably long lifetimes (τ) of ca. 352 ms (λem ≈ 550 nm) for 1-W and 547 ms (λem ≈ 500 nm) for 2-DMF.

A series of alkyl aluminium complexes based on heteroscorpionate ligands were designed as catalysts for the ring-opening polymerisation of cyclic esters and ring-opening copolymerisation of epoxides and anhydrides. Treatment of AlX3 (X = Me, Et) with ligands bpzbeH [bpzbe = 1,1-bis(3,5-dimethylpyrazol-1-yl)-3,3-dimethyl-2-butoxide], bpzteH [bpzte = 2,2-bis(3,5-dimethylpyrazol-1-yl)-1-para-tolylethoxide], and (R,R)-bpzmmH [(R,R)-bpzmm = (1R)-1-{(1R)-6,6-dimethyl-bicyclo[3.1.1]-2-hepten-2-yl}-2,2-bis(3,5-dimethylpyrazol-1-yl)ethoxide] for 2 hours at 0 °C afforded the mononuclear dialkyl aluminium complexes [AlMe2{κ2-bpzbe}] (1), [AlEt2{κ2-bpzbe}] (2), [AlMe2{κ2-(R,R)-bpzmm}] (3) and [AlEt2{κ2-(R,R)-bpzmm}] (4), and the dinuclear dialkyl complexes [AlMe2{κ2-bpzte}]2 (5) and [AlEt2{κ2-bpzte}]2 (6). The molecular structures of the new complexes were determined by spectroscopic methods and confirmed by X-ray crystallography. The alkyl-containing aluminium complexes can act as highly efficient single-component initiators for the ring-opening polymerisation of ε-caprolactone and l-lactide and for the ring-opening copolymerisation of cyclohexene oxide and phthalic anhydride to give a range of biodegradable polyesters.

We report the formation of a novel multifunctional metal–organic framework (MOF) based on dysprosium(III) ions using pyrene-1,3,6,8-tetrasulfonate (pytet)4− as a ligand, synthesized using a soft hydrothermal route. This material shows a two-dimensional network with small channels along a crystallographic axis and displays intense photoluminescence properties in the solid state at room temperature due to the pyrene derivative ligand. The magnetic properties of this 2D-MOF are also accomplished, confirming slightly frequency-dependent out of phase signals under an applied field of 1000 Oe.

Herein, we report the detailed structural characterization and photoluminescence (PL) properties of two new isostructural coordination polymers (CPs) based on 2-aminonicotinate (2ani) ligand and zinc(II) or cadmium(II) metal ions, namely, [M(μ-2ani)2]n [MII = Zn(1) and Cd(2)]. These compounds are characterized as chiral 2D-layered structures, resulting from the bridging of the 2ani ligands in the MN2O4 coordination shell. Also, strong supramolecular interactions are found to sustain the overall crystal structure, which endows these materials with high stability. The single crystals of 1 exhibit waveguiding behaviour along some preferred orientations. The examination of the polycrystalline samples of both compounds under UV light also shows that the samples exhibit remarkably strong PL emissions, which consist of blue fluorescence and green phosphorescence involving long-lasting phosphorescence (LLP) at low temperature. Fitting of the decay curves confirms the occurrence of short (in the order of nanoseconds) and very large lifetimes (τ ≈ 320 and 560 ms for 1 and 2, respectively) of the wavelengths responsible for their blue and green emissions, respectively, which have been studied using DFT calculations.

We have synthesized a novel family of metal–organic chains based on 4-nitro-1H-pyrazole linker and zinc as metal center. We report the formation of these coordination polymers using hydrothermal routes with water as solvent. These materials display one-dimensional structures with major structural modifications from minimal synthetic variations. What is more interesting, we have carried out antitumor measurements, and we have related these properties with the structural networks. To the best of our knowledge, these materials constitute the first examples of polymeric structures for 4-NO2-pz ligands. NMR and MS spectrometry were used to verify the characterization of the metal complexes in solution to corroborate that these materials are present in the biological assays.

Isostructural dinuclear dysprosium and yttrium coordination compounds based on the 5-nitropicolinic carboxylate ligand were synthesized and characterized. The formation of these air-stable complexes is achieved via solvothermal routes employing water as the reaction solvent. The dysprosium-based complex exhibits single-molecule magnet behavior with frequency dependence of the out-of-phase susceptibility at zero direct-current field. High-resolution mass spectrometry (electrospray ionization) experiments and advanced NMR methods including diffusion NMR techniques were applied on the diamagnetic yttrium analogue and established that these species retained their solid-state structure in solution with hydrodynamic radii of 6.5 A. Full 1H, 13C, 15N, 89Y, Δ1Hcoord, Δ13Ccoord, and Δ15Ncoord NMR data are given, and through the analysis of the Ramsey equation, the first electronic insights of these derivatives are provided.

Detailed structural characterization and photoluminescence properties of four new metal–organic frameworks (MOFs) based on zinc(II) or cadmium(II) metal ions, di- or tricarboxylic aromatic ligands, and bipyridyl-like elongated ancillary linkers, namely, {[Zn2(μ4-bdc)2(μ-pbptz)]·2DMF·3H2O}n (1), {[Cd(μ3-bdc)(μ-pbptz)]·3DMF}n (2), {[Cd3(μ5-btc)2(μ-pbptz)]·2DMF}n (3), and {[Zn2(μ-dhbdc)2(μ-pbptz)(DMF)4]·2DMF·H2O}n (4) (where bdc = benzene-1,4-dicarboxylato, btc = benzene-1,3,5-tricarboxylato, dhbdc = 2,5-dihydroxobenzene-1,4-dicarboxylato, pbptz = 3,6-bis(4-pyridyl)-1,2,4,5-tetrazine, DMF = N,N-dimethylformamide) are reported. The occurrence of large accessible volumes and structural and topological diversity are a constant for crystal structures of these compounds, which is a result of the connectivity established among the metal-carboxylato building units formed in each case. Three-dimensional (3D) pcu frameworks of compounds 1 and 2 are built from the linkage of dimeric cores (established by the coordinat...

A new cadmium/6-aminonicotinate-based coordination polymer (CP) with an unprecedented multicolored and long-lasting emission is reported. This material shows a blue fluorescence which rapidly turns to green persistent phosphorescence with a lifetime of nearly 1 s. Time-dependent density functional theory calculations revealed that electronic transitions arising from both first excited singlet and triplet states involving ligand-centered and ligand-to-metal charge-transfer mechanisms are responsible for such behavior.

A series of ruthenium(II) arene complexes (arene = p-cymene, hexamethylbenzene and benzene) containing dibenzoylmethane ligand (DBMH) of formula [(arene)Ru(DBM)Cl] and their ionic derivatives bearing PTA (1,3,5-triaza-7-phosphaadamantane), of formula [(arene)Ru(DBM)(PTA)]X (X = PF6- or SO3CF3-) have been synthesized and fully characterized. The solid-state structures of five complexes have been determined by single-crystal X-ray diffraction. These ruthenium materials exhibit intense photoluminescence emission at room temperature in the solid state. All complexes effectively bind to calf thymus DNA through intercalative/electrostatic interactions with more affinity for DNA minor groove. Finally, the antitumor activity of both ligand and complexes was evaluated against the U266 and RPMI human multiple myeloma cell lines, and some of them showed a cytotoxic and pro-apoptotic effect toward both cell lines.

We report on a process for immobilizing metal–organic chains constructed of dysprosium and sodium ions based on 5-aminopyridine-2-carboxylic acid, onto silicon-based surfaces coated with poly(acrylic acid) (PAA) polymer brushes. Atomic force microscopy (AFM) and fluorescence microscopy were used to study the film morphology before and after the deposition of the 1D metallo-organic polymer. The covalent linkage of the dysprosium complex is also confirmed using X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray spectroscopy (SEM-EDS) analysis. Using magnetic force microscopy (MFM) we particularly addressed the magnetic properties of the grafted metal–organic structure. These results suggest a simple and effective method for incorporation of such molecules onto nanometric surfaces.

A novel metal-organic framework (MOF) based on strontium alkaline-earth metal and 2-amino-1,4-benzenedicarboxylic acid (NH2-bdc) has been developed. This material is formed by a linear succession of face-sharing strontium polyhedra bridged by an organic ligand molecule to give a three-dimensional network with rhombohedral one-directional channels. This MOF is stable in polar organic solvents and up to 250 °C. The basic catalytic activity of both strontium metal nodes and amino groups of the ligand was tested in Knoevenagel condensation reactions. The influence of the temperature and reaction solvent over the catalytic performance of the MOF catalyst was demonstrated. The strontium/amino-containing MOF material evidenced a remarkable activity as compared to other conventional alkaline oxides typically used as reference basic solid catalysts. The novel MOF material showed remarkable activity and structural stability during five consecutive catalytic runs with no evidence of activity loss under the best reaction conditions found in this study., The authors wish to thank Spanish Ministry of Science and Innovation for the financial support to the CICYT Project (CTQ2015-64526-P).

A novel URJC-3 material based on cobalt and 5,5′-(diazene-1,2-diyl)diisophthalate ligand, containing Lewis acid and basic sites, has been synthesized under solvothermal conditions. Compound URJC-3, with polyhedral morphology, crystallizes in the tetragonal and P4 3 2 1 2 space group, exhibiting a three-dimensional structure with small channels along a and b axes. This material was fully characterized, and its hydrogen adsorption properties were estimated for a wide range of temperatures (77–298 K) and pressures (1–170 bar). The hydrogen storage capacity of URJC-3 is quite high in relation to its moderate surface area, which is probably due to the confinement effect of hydrogen molecules inside its reduced pores of 6 Å, which is close the ionic radii of hydrogen molecules. The storage capacity of this material is not only higher than that of active carbon and purified single-walled carbon nanotubes, but also surpasses the gravimetric hydrogen uptake of most MOF materials., This work has been support by “Comunidad de Madrid” (project: ALCCONES (S2013/MAE‐2985) and Spanish Ministry of Science and Innovation (project: MOF4Energy (CTQ2015‐64526) and grant (FPI BES‐2016‐076433).

We report on the formation of a triazolopyrimidine derivative ligand, 7-amino-5-methyl-1,2,4-triazolo[1,5-a]pyrimidine (7-amtp), and a new family of coordination compounds based on this ligand and zinc as metal ion, synthesized by conventional routes. These materials possess different mononuclear structures, namely [ZnCl2(7-amtp)2] (1), [Zn(7-amtp)2(H2O)4](NO3)2·2(7-amtp)·6H2O (2) and [Zn(7-amtp)2(H2O)4](SO4)·1.5H2O (3) derived from the use of different zinc (II) salts, in such a way that the counterions govern the crystallization to a large extent. These compounds present and show variable luminescent properties based on ligand-centred charge transfers which have been deeply studied by Time Dependent Density Functional Theory (TD-DFT) calculations. When these compounds are transferred to solution, preserving complex entities as corroborated by NMR studies, they present interesting anti-diabetic and anti-parasitic capabilities, with a comparatively higher selectivity index than other previously reported triazolopyrimidine-based materials. The results derived from in vivo experiments conducted in mice also confirm their promising activity as anti-diabetic drug being capable of dropping glucose levels after oral administration. Therefore, these new materials may be considered as excellent candidates to be further investigated in the field of luminescent coordination compounds with biomedical applications.

2-Aminoalkylpyridines [H2N(CH2)nC5H4N] (n = 1 or 2) react with [IrHCl{(PPh2(o-C6H4CO))2H}] (1a) in THF to afford hydridoirida-β-ketoimines [IrHCl{(PPh2(o-C6H4CO))(PPh2(o-C6H4CN(CH2)nC5H4N))H}] (2, n = 1; 3, n = 2) with intramolecular N-H···O hydrogen bonding and a dangling pyridine. In protic media 2–3 transform into [IrH(PPh2(o-C6H4CO))(PPh2(o-C6H4C=N(CH2)nC5H4N))] (4, n = 1; 5, n = 2) containing new terdentate PCN ligands in a facial disposition with the phosphorus atom trans to H and an iminoacyl fragment trans to the other phosphorus atom. The formation of 4–5 requires breaking of the hydrogen bond, isomerization, and dehydrochlorination of an intermediate iminium-acyl species to allow the coordination of the nitrogen atom of pyridine to iridium. The reaction of 1a with the N-substituted N-methylaminomethylpyridine allows the synthesis of [IrH(PPh2(o-C6H4CO))(PPh2(o-C6H4C=N(CH3)CH2C5H4N))]ClO4 (6) containing a PCN ligand with an iminium-acyl moiety trans to phosphorus. The reaction of [IrH2{(PPh2(o-C6H4CO))2H}] (1b) with 2-(aminoalkyl)pyridines [H2N(CH2)nC5H4N] (n = 1 or 2) in MeOH requires the presence of KOH to afford the hydrido derivatives [IrH(PPh2(o-C6H4CO))2(NH2(CH2)nC5H4N,κNH2)] (7, n = 1; 8, n = 2) were the ligands are amino-coordinated with a dangling pyridine. The reaction occurs with hydrogen evolution and transfer of hydrogen from a hydroxyl in the solvent to iridium. Single-crystal X-ray diffraction analysis was performed on 3, 4, 6, and 8.

We have synthesized a novel zinc metal–organic framework (MOF) under mild hydrothermal routes using 5-aminotetrazole and methyl-2-amino-4-isonicotinate anionic ligands. The MOF exhibits a three-dimensional structure with intense blue-greenish photoluminescence emission at room temperature in the solid state. The luminescence, porosity, and adsorption capacity for CO2 and H2 of the Zn-based MOF have been fully determined using a combination of computational methods and experimental techniques. The synthesized Zn-based compound in this study exhibited a remarkable in vivo anti-diabetic activity and low in vitro cell toxicity.

We have designed and synthesized two novel vanadium coordination compounds using 1H-benzimidazole-2-carboxylic acid and 5-aminopyridine-2-carboxylic acid. These two materials have a mononuclear structure with crystallization water molecules in the network. Both compounds exhibit intense photoluminescence emission at room temperature in the solid state and show in vivo antidiabetic activity together with low in vitro cell toxicities. Luminescence theoretical studies have been performed.

[RhCl(NCO)(nbyl)(PR3)] (nbyl = σ-norbornenyl; NCO = quinoline-8-acyl; R = p-F-C6H4) (1) has been synthesized by the reaction of [Rh(nbd)Cl]2 (nbd = norbornadiene) with 2 equivalents of NCHO (quinoline-8-carbaldehyde) and 2 equivalents of PR3. Compound 1 has been fully characterized in solution and also in the solid state by X-ray diffraction. Compound 1 shows low stability in solution and undergoes slow ring closure isomerization to [RhCl(NCO)(ntyl)(PR3)] (ntyl = σ-nortricyclyl) (2) after 12 hours. Reaction of 1 with an extra equivalent of aldehyde (NCHO) and PR3 led to the formation of [RhCl(H)(NCO)(PR3)2] (3) and an equivalent of ketone, which is a hydroacylation product. The catalytic activity of 3 in the hydroacylation of nbd with NCHO is reported as well as the catalytic activity of compound 1. Compounds 1 and 3 are proposed as intermediate species in the catalytic hydroacylation of norbornadiene with NCHO.

A novel metal–organic chain constructed of dysprosium and sodium ions based on 5-aminopyridine-2-carboxylic acid has been synthesized and characterized. The formation of this 1D-MOF is achieved using a soft solvothermal route with dimethylformamide as solvent. This material displays intense photoluminescence properties in the solid state at room temperature and exhibits SIM behavior with frequency dependence of the out-of-phase susceptibility at zero dc field. More interesting, we report here the magnetic field dependent cytotoxicity and multidrug-resistant properties of this 1D-MOF. This multidisciplinary preliminary study of the applications of this metal complex opens up the possibility of further investigations in the fields of metal-based drugs, luminescence and magnetism.

Three novel metal–organic-frameworks (MOFs) based on dysprosium as the metal and dicarboxylic ligands have been solvothermally synthesized with the aim of studying and modulating their magnetic properties according to the variation of the distances between metal centers. These materials display intense photoluminescence properties in the solid state at room temperature. In addition, a very interesting property of compound 1 is that it exhibits slow relaxation of magnetization with an activation energy barrier of 32 K. Magneto-structural correlations have been analyzed.

A new dysprosium based Metal-Organic Framework with {[Dy(dhbdc)(DMF)]·DMF} formula has been obtained from solvothermal reaction with 2,5-dihydroxyterephthalic acid ligand and dysprosium chloride. This coordination polymer has been characterized and its crystal structure has been solved by X-ray diffraction methods elucidating a three-dimensional network. Magnetic studies of this compound reveal the existence of weak antiferromagnetic interactions among the metal ions with θ value of −0.26 K. Dynamic ac magnetic susceptibility measurements were carried out under an external dc field of 1 kOe, highlighting that at high frequencies two relaxation processes can be observed. However, when studying the diamagnetically diluted analogue 1, a single relaxation process was detected highlighting the effect of the weak but not negligible exchange interactions. Finally, photoluminescence measurements were performed at different temperatures with the aim of getting a more representative characterization of the emissive performance of the material for potential applications in lighting and thermometry., Financial support was given by Junta de Andalucía (Spain) (project number FQM-394 and FQM-1484), University of the Basque Country (GIU 17/13), Gobierno Vasco/Eusko Jaurlaritza (IT1005-16) and the Spanish Ministry of Economy and Competitiveness (MCIU/AEI/FEDER, UE) (PGC2018-102052-A-C22, PGC2018-102052-B-C21 and CTQ-2015-64049-C3-3R). The authors thank for technical and human support provided by SGIker of UPV/EHU and European funding (ERDF and ESF). A.Z.-L. is grateful to the Government of the Basque Country for the predoctoral fellowship

Some series of isostructural chains with general formula [M(diclof)(HO)]·(EtOH) have been obtained from reaction between diclofenac ligand (diclof) and first row transition salts (M = Mn (1),Ni (2) and Co (3)). These monodimensional coordination polymers have been characterized and their crystal structures have been solved by X-ray diffraction methods, elucidating isostructural compounds that are chains with water molecules acting as bridge between different metallic centers, while diclofenac ligands are coordinated to the octahedral coordination environment of the same. Magnetic studies of these complexes have revealed the existence of moderate ferromagnetic interactions among manganese, nickel and cobalt ions, with J values of 0.1, 0.60 and 3.3 cm, respectively. It must be highlighted that in vitro leishmanicidal activity of these new complexes has been studied against three different strains of Leishmania spp. showing a higher efficacy than the reference drug Glucantime® and demonstrating the potential of these novel materials based on coordination chemistry., Financial support was provided by Junta de Andalucía , Spain (project number FQM-394 and FQM-1484 ), University of the Basque Country , Spain ( GIU 17/13 ) and the Spanish Ministry of Economy and Competitiveness , Spain ( MCIU/AEI/FEDER , UE) (PGC2018-102052-A-C22 and PGC2018-102052-B-C21). The authors thank for technical and human support provided by SGIker of UPV/EHU , Spain and European funding ( ERDF and ESF, Europe). R.M-E. is grateful for a FPU Grant ( FPU14/01537 ) from the Ministry of Education of Spain.

We aimed to study the effect of vanadium(V) exposure on cell viability, nuclear DNA (nDNA) and mitochondrial DNA (mtDNA) and to elucidate if these effects can be reverted by co-exposure to V and manganese (Mn). HepG2 cells were incubated with various concentrations of bis(maltolato)oxovanadium(IV) or MnCl2 for 32 h for viability study. The higher concentrations (59 μM V, 54 nM Mn and 59 μM V+54 nM Mn) were used to study DNA damage and uptake of V and Mn. Comet assay was used for the study of nDNA damage; mtDNA damage was studied by determining deletions and number of copies of the ND1/ND4 mtDNA region. Cellular content of V and Mn was determined using ICPMS. Cellular exposure to 59 μM V decreased viability (14%) and damaged nDNA and mtDNA. This effect was partially prevented by the co-exposure to V + Mn. Exposure to V increased the cellular content of V and Mn (812.3% and 153.5%, respectively). Exposure to Mn decreased the content of V and Mn (62% and 56%, respectively). Exposure to V + Mn increased V (261%) and decreased Mn (56%) content. The positive effects on cell viability and DNA damage when incubated with V + Mn could be due to the Mn-mediated inhibition of V uptake.

A series of triazolopyrimidine transition metals complexes have been synthesized by the reaction between the derivative 5,7-dimethyl-1,2,4-triazolo[1,5-a]pyrimidine (dmtp) with M(NO3)2·XH2O (M = Cu(II), Co(II), Ni(II) and Zn(II)). These four compounds have been characterized by spectroscopic and thermal analysis and the crystal structure of the Cu(II) one has been solved by X-ray diffraction methods. The in vitro antiparasitic activity of these complexes against four leishmania spp. strands and their toxicity against macrophage host cells have also been studied, in order to elucidate the influence of different metal centres in the leishmanicidal effect to fight neglected tropical diseases.

Acyl(σ-norbornenyl)rhodium(III) dimer [Rh(μ-Cl)(C9H6NCO)(C7H9)L]2 (1) (C7H9 = σ-norbornenyl; L = 4-picoline, isoquinoline) reacts with diphenylphosphine oxide (SPO) to undergo a one-pot reaction in...

Functionalized magnetite nanoparticles (FMNPs) and functionalized mesoporous silica nanoparticles (FMSNs) were synthesized by the conjugation of magnetite and mesoporous silica with the small and fluorogenic benzothiazole ligand, that is, 2(2-hydroxyphenyl)benzothiazole (hpbtz). The synthesized fluorescent nanoparticles were characterized by FTIR, XRD, XRF, 13C CP MAS NMR, BET, and TEM. The photophysical behavior of FMNPs and FMSNs in ethanol was studied using fluorescence spectroscopy. The modification of magnetite and silica scaffolds with the highly fluorescent benzothiazole ligand enabled the nanoparticles to be used as selective and sensitive optical probes for zinc ion detection. Moreover, the presence of hpbtz in FMNPs and FMSNs induced efficient cell viability and zinc ion uptake, with desirable signaling in the normal human kidney epithelial (Hek293) cell line. The significant viability of FMNPs and FMSNs (80% and 92%, respectively) indicates a potential applicability of these nanoparticles as in vitro imaging agents. The calculated limit of detections (LODs) were found to be 2.53 &times, 10&minus, 6 and 2.55 &times, 6 M for Fe3O4-H@hpbtz and MSN-Et3N-IPTMS-hpbtz-f1, respectively. FMSNs showed more pronounced zinc signaling relative to FMNPs, as a result of the more efficient penetration into the cells.

Two new squaramide-based platinum(II) complexes C1 and C2 have been synthesized and fully characterized. Their photoresponse has been assessed and is discussed. A remarkable enhancement in the DNA binding activity has been observed for both complexes, up on irradiation. For C2, the release of Pt(II) provoked by its irradiation has been studied. The response of C2 has been found to be regulated by the presence of oxygen. In vitro cytotoxicity tests show an enhancement in the activity of complex C2 after selective irradiation under hypoxic conditions. Resulting Pt(II) species have been isolated and characterized by various analytical methods establishing this type of squaramido-based complexes as a proof of concept for new Pt(II) photocages.

The reactivities of cobalt(II) and manganese(II) salts toward HDMV (N,N′-dimethylvioluric acid monohydrate) were studied. Reaction of cobalt(II) chloride hexahydrate with HDMV in water–methanol medium at pH = 8.0 led to the formation of a cobalt(III) complex [CoIII(DMV)3]·0.5H2O (1), whereas the interaction of manganese(II) chloride tetrahydrate with HDMV under similar reaction conditions afforded [MnII(H2O)6](DMV)2 (2). Dimethylviolurate anion behaves as a bidentate ligand in 1 and counteranion in 2. Both compounds were characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy, cyclic voltammetry and thermogravimetric analysis. Presence of Co(III) in 1 indicates the aerial oxidation of the cobalt(II) precursor. In 1, Co(III) adopts a distorted octahedral [CoN3O3] coordination environment through bonding to the three dimethylviolurato anions. In 2, the [Mn(H2O)6]2+ cations and (DMV)− anions are assembled by multiple hydrogen bonds into a complex 3D H-bonded network. It was analyzed from the topological viewpoint, disclosing a binodal 4,8-connected underlying net with the flu (fluorite) topology. Electrochemical studies reveal that the compounds undergo a quasi-reversible one electron metal centered redox process. DFT studies were carried out to analyze the supramolecular assemblies in the solid state structures, especially lone pair(lp)–π interactions in 1 and H-bonding network in 2.

Bidimensional novel cadmium metal-organic frameworks (MOFs) based on the 1,3-bis(4-pyridyl)propane linker and flexible dicarboxylate ligands derived from glutarate (2-methylglutarate, 2-dimethylglutarate and 3-methylglutarate) have been synthesized by conventional routes. These MOFs show fascinating structural features and they display long lifetime photoluminescence emission in the solid state, at room temperature.

A series of zinc(II) or cadmium(II)-based compounds with elongated dicarboxylate and bipyridine ligands, namely {dma[Cd(μ-azdc)(μ-ac)]·xDMF}n (1), {[Cd2(μ4-azdc)(μ-azdc)(DMSO)4]·DMSO}n (2), [Cd3(μ4-azdc)3(DMF)2]n (3), {[Zn2(μ3-azdc)2(μ-pbptz)]·xDMF}n (4), and {[Zn3(μ4-azdc)3(μ-pbptz)2]·xDMF·yH2O}n (5) (where dma = dimethylammonium, azdc = azobenzene-4,4′-dicarboxylate, ac = acetate, DMF = dimethylformamide, DMSO = dimethylsulfoxide, pbptz = 3,6-bis(4-pyridyl)-1,2,4,5-tetrazine), have been synthesized under solvothermal conditions and structurally characterized by single-crystal X-ray diffraction. Crystal structures range from 2D to 3D systems according to the presence of the pbptz co-ligand, which aids the layers established by azdc ligands to increase their dimensionality. The structural diversity found in each system is the result of three factors that govern the assembling process by modulating the coordination mode of the azdc ligands: the employed solvent, counterion and metal : ligand stoichiometry. A common structural feature of these compounds is the highly open architectures achieved due to the length of the employed ligands, which favours the resulting frameworks to be interpenetrated by different degrees depending on the network topology. A careful computational analysis of the void systems of the compounds permits establishing a relationship of this phenomenon with the pore size. The photoluminescence properties of all compounds have been also investigated.

Six novel NiII complexes, ranging from mononuclear to tetranuclear, have been prepared from the polytopic symmetrical Mannich base ligand N,N′-dimethyl-N,N′-bis(2-hidroxy-3-formyl-5-bromo-benzyl)ethylenediamine (H2L) and different anionic coligands: [Ni(H2L)(NO3)(H2O)]NO3·H2O (1), [Ni2(μ-L)(acac)2(H2O)]·CH3CN (2), [Ni2(μ-L)(μ-OAc)(NCS)] (3), [Ni3(μ-L)2(μ-OH2)2(H2O)(CH3CN)](NO3)2·4CH3CN (4), [Ni4(μ-L)2(μ-OAc)2(μ-OCH3)2]·6H2O·2CH3OH (5) and [Ni4(μ-L)2(μ-OAc)2(μ-N3)2]·2H2O·CH3OH (6). These complexes have been characterized by single crystal X-ray diffraction, magnetic measurements and DFT theoretical calculations. The structural analysis of these complexes reveals that the anionic coligand and reaction conditions play a fundamental role in determining their final structures and magnetic properties. Compound 1 contains a monomeric cationic unit with the nickel ion coordinated in the external O4 site of the compartmental ligand H2L, which acts in a neutral zwitterionic form. Complexes 2 and 3 are dinuclear Ni2 neutral entities, in which the NiII ions are connected through two μ-phenoxido bridging groups. The Ni(O)2Ni bridging fragment in 2 is almost planar, whereas in 3 is bent due to the additional presence of a syn–syn acetate bridge connecting the NiII atoms. Complex 4 has a bent trinuclear structure with double μ-phenoxido/μ-water bridges between the central and terminal nickel atoms. Complexes 5 and 6 are Ni4 complexes with defective dicubane structures, in which triple μ-phenoxido/μ1,1,1-X/syn–syn acetate and double μ-phenoxido/μ1,1,1-X mixed bridges connect central and terminal NiII atoms, whereas double μ1,1,1-X bridging ligands link the central NiII ions (X = methoxido and azido groups for 5 and 6, respectively). Magnetic susceptibility measurements reveal that complex 2 shows a moderate antiferromagnetic interaction between the NiII ions through the double di-μ-phenoxido bridge, leading to a S = 0 ground state. Compared to 2, complex 3 shows a much weaker magnetic exchange interaction due the counter-complementarity effect provoked by the additional presence of the syn–syn acetate bridging group, as well as the non-planarity of the bridging fragment. In complex 4, the double μ-phenoxido/μ-water mixed bridges lead to very weak antiferromagnetic interactions between the central and external NiII ions. Overall ferromagnetic interactions are found for 3, 5 and 6, although in 5 not all the magnetic pathways transmit ferromagnetic interactions. A detailed analysis of the magnetic exchange interactions transmitted through the different pathways as well as DFT calculations on the X-ray structures of compounds 2–6 were performed to support the magneto-structural data of these compounds.

The ligand 4,4′-(1,2,4,5-tetrazine-3,6-diyl)dibenzoic acid has been designed and explored with the aim of using it as a linker to construct three-dimensional metal–organic frameworks (MOFs). We have been successful in the formation of a potassium 3D-MOF using this novel linker. This compound has a three-dimensional structure, wherein the layers formed by potassium ions and carboxylate groups are separated by this organic ligand. Luminescence and cytotoxicity studies have been performed. We used molecular simulations to predict the porous properties of an isoreticular compared to IRMOF-16 based on this linker due to the similarity of the newly designed ligand with p-terphenyl-4,4′′-dicarboxylate present in IRMOF-16.

2-Aminopyridines (H2NC5H3RN) react with [IrH2{(PPh2(o-C6H4CO))2H}] (1) in refluxing methanol to afford [IrH(PPh2(o-C6H4CO))(PPh2(o-C6H4CHNHC5H3RN))] (R = H (2), R = CH3 (3)) containing new terdentate PCN ligands in a facial disposition with the phosphorus atom trans to H and the new alkyl fragment trans to the other phosphorus atom. The formation of 2 and 3 requires imination of the hydroxycarbene moiety in 1, iridium to carbon hydrogen transfer, and coordination of the nitrogen atom of pyridine to iridium. In refluxing methanol the reaction of 1 with the N-substituted 2-(methylamino)pyridine leads to [IrH(PPh2(o-C6H4CO))(PPh2(o-C6H4C(OH)N(CH3)C5H4N))] (4), containing a PCN ligand with a hydroxyalkyl moiety trans to phosphorus and the nitrogen atom of pyridine trans to hydride. By performing this reaction in the presence of KOH, complex [IrH(PPh2(o-C6H4CO))(PPh2(o-C6H4C(OCH3)N(CH3)C5H4N))] (5), with a methoxyalkyl moiety in the PCN ligand and similar stereochemistry to that of 2 and 3, is obtained. In chl...

We report here 1,1- and 1,2-insertion reactions of small unsaturated molecules in the N–B bonds of two boron guanidinates, (Me2N)C(NiPr)2BCy2 (1) and {iPr(H)N}C(NiPr){N(p-tBu-C6H4)}BCy2 (2), and two bisboron guanidinates(2–), {iPr(BCy2)N}C(NiPr){N(p-tBu-C6H4)}BCy2 (3) and {iPr(C8H14B)N}C(NiPr){N(p-Me-C6H4)}BC8H14 (4), the latter being prepared for the first time by double deprotonation of the corresponding guanidine with the 9-borabicyclo[3.3.1]nonane dimer, (H-BC8H14)2. Compounds 1–4 easily insert aromatic isonitriles, XylNC (Xyl = 2,6-Me2-C6H3) and (p-MeO-C6H4)NC, to give the expected diazaboroles 5–12, some of them being structurally characterised by X-ray diffraction. Interestingly, the BC8H14 derivatives 11 and 12 are in a fast temperature-dependent equilibrium with the de-insertion products, whose thermodynamic parameters are reported here. A correlation between these equilibria and the puckered heterocyclic structure found in the solid state for 11, and confirmed by DFT calculations, is also established. Reactions of the aforementioned guanidinates with CO are more sluggish or even precluded, and only one product, {iPr(H)N}C{N(p-tBu-C6H4)}(NiPr)(CO)BCy2 (13), could be isolated in moderate yields. The 1,2-insertions of benzaldehyde in compounds 1, 2 and 4 are reversible reactions in all cases, and only one of the insertion products, {iPr(H)N}C{N(p-tBu-C6H4)}(NiPr)(PhHCO)BCy2 (16a), was isolated and diffractrometrically characterised. Likewise, CO2 reversibly inserts into a N–B bond of 2 to give {iPr(H)N}C{N(p-tBu-C6H4)}(NiPr)(CO2)BCy2 (19) with a conversion of ca. 9%. In all these equilibria, de-insertion is always favoured upon increasing the temperature.