416 research outputs found
Unprecedented chemical transformation: crystallographic evidence for 1,1,2,2-tetrahydroxyethane captured within an Fe6Dy3 single molecule magnet
A nonanuclear {Fe6Dy3} coordination cluster displaying SMM
behaviour in which an unprecedented chemical transformation
provides structural information for the existence of 1,1,2,2-tetrahydroxyethane
is reported
Tubular glassy carbon microneedles with fullerene-like tips for biomedical applications
Glassy carbon, in general, is made by the pyrolysis of polymeric materials and has been the subject of research for at least fifty years. However, as understanding its microstructure is far from straightforward, it continues to be an area of active research. Glassy carbon adopts different allotropes depending on the hybridizations of the C–C bond, that is, sp, sp2, or sp3. Furthermore, a variety of short-range ordering effects can interact with each other and this, along with the effects of microporosity, grain boundaries, and defects, render this a fascinating material. Following the nanoarchitectonics concept of bottom-up creation of functional materials, we use methane rather than a polymer to form glassy carbon. Here we show that tubular glassy carbon microneedles with fullerene-like tips form when methane undergoes pyrolysis on a curved alumina surface. X-ray diffraction of these glassy carbon tubules shows long-range order with a d-spacing of 4.89 Å, which is indicative of glassy carbon. Raman spectroscopy shows the material to be graphitic in nature, and SEM shows the fullerene-like structure of the material. This work provides new insights into the structure of glassy carbons relevant to the application of glassy carbons as a biomaterial, for example, as a new form of carbon-based microneedles. Since metallic needles can introduce toxic/allergenic species into susceptible subjects, this alternative carbon-based microneedle form has great potential as a replacement biomedical material for metallic needles in the field of neural engineering and as acupuncture needles
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Recent bio-advances in metal-organic frameworks
Metal-organic frameworks (MOFs) have found uses in adsorption, catalysis, gas storage and other industrial applications. Metal Biomolecule Frameworks (bioMOFs) represent an overlap between inorganic, material and medicinal sciences, utilising the porous frameworks for biologically relevant purposes. This review details advances in bioMOFs, looking at the synthesis, properties and
applications of both bioinspired materials and MOFs used for bioapplications, such as drug delivery, imaging and catalysis, with a focus on examples from the last five years
Review: Recent advances of one-dimensional coordination polymers as catalysts
This review aims to provide reports of one dimensional (1-D) coordination polymers that have been used as catalysts in various organic reactions in the last decade, covering the literature from 2007 and onwards. The CPs have been mainly categorized into homometallic and heterometallic compounds; additional parameters such as the metal and ligand selection for the CP are discussed to provide a more detailed look into each system
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Recent advances in the coordination chemistry of benzotriazole-based ligands
With the use of N-donor ligands in coordination chemistry receiving significant interest and attention in the last few decades, benzotriazole has emerged as an ideal molecule that provides many synthetic advantages and reliable routes towards polynuclear coordination clusters and coordination polymers. In order to fully realise this potential, the current work provides a systematic study of the recent advances on the use of benzotriazole and its derivatives as ligands in coordination chemistry. The reported complexes have been primarily categorized in regards to the exact linker used and its role in the resulting architecture (either as a main or as a secondary ligand). Important structural information, as well as notable properties (such as magnetism, catalysis, luminescence, bio-applications) are also mentioned for the compounds
A 12-fold ths interpenetrated network utilizing a glycine-based pseudopeptidic ligand
We report the synthesis and characterization of a 3D Cu(II) coordination polymer, [Cu3(L1)2(H2O)8]·8H2O (1), with the use of a glycine-based tripodal pseudopeptidic ligand (H3L1 = N,N’,N’’-tris(carboxymethyl)-1,3,5-benzenetricarboxamide or trimesoyl-tris-glycine). This compound presents the first example of a 12-fold interpenetrated ths net. We attempt to justify the unique topology of 1 through a systematic comparison of the synthetic parameters in all reported structures with H3L1 and similar tripodal pseudopeptidic ligands. We additionally explore the catalytic potential of 1 in the A3 coupling reaction for the synthesis of propargylamines. The compound acts as a very good heterogeneous catalyst with yields up to 99% and loadings as low as 3 mol%
A new family of high nuclearity CoII/DyIII coordination clusters possessing robust and unseen topologies
Mixing Co(NO3)2·6H2O/Dy(NO3)3·6H2O/(E)-4-(2-hydroxy-3-methoxybenzylideneamino)-2,3-dimethyl-1-phenyl-1,2-dihydropyrazol-5-one (HL)/pivalic acid/Et3N in various solvents results in the synthesis of seven compounds formulated as [CoII2DyIII2(μ3-MeO)2(L)2(piv)4(NO3)2] (3), [CoIIDyIII3(μ3-MeO)2(μ2-MeO)2(L)2(piv)2(NO3)3]·2(CH3OH) (4·2CH3OH), 2[CoII4DyIII4(μ2-O)2(μ3-OH)4(L)4(piv)8][CoII2DyIII5(μ3-OH)6(L)2(piv)8(NO3)4] (5), [CoII4DyIII4(μ2-O)2(μ3-OH)4(L)4(piv)8]·2(CH3CN) (6·2CH3CN), [CoII2DyIII5(μ3-OH)6(L)2(piv)8(NO3)4]·4(CH3CN) (7·4CH3CN), [CoII2DyIII2(μ3-OH)2(L)2(piv)2(NO3)2(EtOH)2(H2O)2](NO3)2·(EtOH) (8·EtOH) and [CoII4DyIII4(μ2-O)2(μ3-OH)4(L)4(piv)8] (9) with robust and unseen topologies. These show that the temperature and reaction time influence the formation of the final product. Preliminary magnetic studies, performed for 6 and 7 in the temperature range 2-300 K, are indicative of Single Molecule Magnet (SMM) behaviour. Moreover, analysis of the catalytic properties of compound 3 as an efficient catalyst for the synthesis of trans-4,5-diaminocyclopent-2-enones from 2-furaldehyde and primary amines has been carried out
Synthesis, characterization, magnetic properties, and topological aspects of isoskeletal heterometallic hexanuclear Co II 4 Ln III 2 coordination clusters possessing 2,3,4M6-1 Topology
The reaction of (E)-2-(2-hydroxy-3-methoxybenzylideneamino)phenol (H2L1) with Co(NO3)26H2O and LnCl3x(H2O) afforded a family of hexanuclear heterometallic coordination clusters (CCs) formulated as [CoII4LnIII2(µ3-OH)2(L1)4Cl2(NO3)2(MeOH)4] 3(Et2O) where Ln is Y (1), Gd (2), Dy (3), and Tb (4). All the compounds are stable in solution as confirmed by ESI-MS studies. The compounds can be described as twisted boat-like and possess a 2,3,4M6–1 topology. The reaction of (E)-2-(5-bromo-2-hydroxy-3-methoxybenzylideneamino)phenol (H2L2) with Co(NO3)26H2O and DyCl3x(H2O) afforded [CoII4DyIII2(µ3-OH)2(L2)4Cl2(NO3)2(MeOH)4] (5), which is isoskeletal to compounds 1–4. Magnetic studies performed over the temperature range 1.8–300 K show that compound 3 undergoes slow magnetic relaxation
Dinuclear Lanthanide (III) coordination polymers in a domino reaction
A systematic study was performed to further optimise the catalytic room-temperature synthesis of trans-4,5- diaminocyclopent-2-enones from 2-furaldehyde and primary or secondary amines under a non-inert atmosphere. For this purpose, a series of dinuclear lanthanide (III) coordination polymers were synthesised using a dianionic
Schiff base and their catalytic activities were investigated
Isoskeletal Schiff base polynuclear coordination clusters: synthetic and theoretical aspects
This work addresses and enlightens synthetic aspects derived from our effort to systematically construct isoskeletal tetranuclear coordination clusters (CCs) of the general formula [TR2Ln2(LX)4(NO3)2(solv)2] possessing a specific defected dicubane topology, utilizing various substituted Schiff base organic ligands (H2LX) and NiII/CoII and Dy(OTf)3 salts. Our synthetic work is further supported by DFT studies
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