80 research outputs found
The synthesis, structure, topology and catalytic application of a novel cubane-based copper(II) metal-organic framework derived from a flexible amido tripodal acid
A novel chiral metal-organic framework, [Cu-4(HL)(2)(H2O)(4)(MeO)(4)](n) (1), has been successfully synthesized from a tripodal flexible ligand (2S, 2'S, 2 '' S)- 2,2', 2 ''-(benzenetricarbonyltris(azanediyl)) tripropanoic acid (H3L). Compound 1 was characterized by IR and X-ray powder diffraction analysis. The structure was determined by X-ray single crystal diffraction analysis revealing that 1 possesses a 3D network, featuring a tetranuclear cubane-type secondary building block [Cu-4(MeO)(4)](4+), formed via the connection of four metal ions to four methoxide ions. These secondary building blocks are linked by four different HL2- ligands to construct a porous three dimensional framework of the dia topology with one-dimensional channels. Compound 1 also acts as a heterogeneous catalyst for the diastereoselective nitroaldol (Henry) reaction, providing high yields (up to 91%) and good diastereoselectivities under ambient conditions. This catalyst can be recycled without significant loss of activity
Single-Crystal-to-Single-Crystal Transformation of a Novel 2-Fold Interpenetrated Cadmium-Organic Framework with Trimesate and 1,2-Bis(4-pyridyl)ethane into the Thermally Desolvated Form Which Exhibits Liquid and Gas Sorption Properties
A novel 2-fold interpenetrated pillared cadmium metal organic framework namely [Cd(HBTC)-BPE](n)center dot nDMF has been synthesized using 1,3,5-benzenetricarboxylic acid and 1,2-bis(4-pyridyl)ethane (BPE). This compound has been desolvated and subjected to various liquids and gases for sorption studies. Structures of the assynthesized (1) desolvated (2) and resolvated in benzene (3) have been determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis IR spectra, and thermogravimetric/differential scanning calorimetry analysis. Single crystal X-ray analysis revealed a 2-fold interpenetrated, three-dimensional (3D) framework which exhibits a 3,5-connected network with the Schlafli symbol of [(6(3))(6(9).8) and hms topology. Compound I exhibits a temperature-induced single-crystal-to-single-crystal (SC SC) transformation upon the release of N,N'-dimethylformamide molecules forming compound 2 (stable up to 300 C). SC SC transformation is also observed when it is immersed in benzene, chloroform, 1,4dioxane, and tetrahydrofuran. The uptake of different solvent molecules was analyzed, and desolvated samples selectively adsorb benzene, chloroform, 1,4-dioxane, and THF molecules over other selected polar solvents. Gas (N-2, CO2, and N2O) sorption experiments were also performed and the structure showed 2.5% N-2 4.5% CO2, and 3.4% N2O absorption by mass at room temperature and moderate gas pressures (similar to 10 bar)
Queen Nefertari, the royal spouse of pharaoh Ramses II: a multidisciplinary investigation of the mummified remains found in her tomb (QV66)
Queen Nefertari, the favourite Royal Consort of Pharaoh Ramses II (Ancient Egypt, New Kingdom, 19th Dynasty c. 1250 BC) is famous for her beautifully decorated tomb in the Valley of the Queens. Her burial was plundered in ancient times yet still many objects were found broken in the debris when the tomb was excavated. Amongst the found objects was a pair of mummified legs. They came to the Egyptian Museum in Turin and are henceforth regarded as the remains of this famous Queen, although they were never scientifically investigated. The following multidisciplinary investigation is the first ever performed on those remains. The results (radiocarbon dating, anthropology, paleopathology, genetics, chemistry and Egyptology) all strongly speak in favour of an identification of the remains as Nefertari's, although different explanations-albeit less likely-are considered and discussed. The legs probably belong to a lady, a fully adult individual, of about 40 years of age. The materials used for embalming are consistent with Ramesside mummification traditions and indeed all objects within the tomb robustly support the burial as of Queen Nefertari.Michael E. Habicht, Raffaella Bianucci, Stephen A. Buckley, Joann Fletcher, Abigail S. Bouwman, Lena M. Őhrström, Roger Seiler, Francesco M. Galassi, Irka Hajdas, Eleni Vassilika, Thomas Böni, Maciej Henneberg, Frank J. Rühl
Findings in ancient Egyptian mummies from tomb KV64, Valley of the Kings, Luxor, with evidence of a rheumatic disease
Objective: In 2011, a spectacular find was made in the Valley of the Kings, Egypt - a well-known archaeological site, where pharaohs were buried during the New Kingdom (ca. 1500-1100 BCE). A team from the University of Basel's Kings' Valley Project discovered a tomb (KV64) containing two mummies that were buried in different time episodes (unidentified elite burial, 18th dynasty, and Nehemesbastet, 22nd dynasty).
Method: Anthropological investigations of the mummies were performed using portable X-ray and photographic documentation.
Results and conclusion: The first burial was an adult individual with bilateral pathological changes at the temporomandibular joints (TMJs), most likely of inflammatory origin, possibly psoriatic arthritis. Investigations of the second burial revealed an intact body of a younger female individual
Anionic zinc-trimesic acid MOFs with unusual topologies: Reversible hydration studies
The reaction of 1,3,5-benzenetricarboxylic acid (H3BTC) with ZnSO4 center dot 6H(2)O in a DMF-water solution afforded two new metal-organic frameworks [Zn-6(mu(3)-OH)(2)(BTC)(4)(DMF)(2.5)(H2O)(2)]center dot[Zn(H2O)(3)(DMF)(3)]center dot 3.1H(2)O (1) and Zn-2(HBTC)(BTC)(H2O)(3)]center dot DMA center dot 3H(2)O (2). Both compounds are thermally stable and can be prepared reproducibly. Rehydration experiments on compound 2 demonstrate reversible dehydration and rehydration while 1 rehydrates to a different crystalline material. Network analysis revealed a binodal (3,6)-net for 1 and a (3,5)-net for 2, both rare topologies
On the Potential of THz Time-Domain Spectroscopy to Identify Typical Ancient Egyptian Embalming Materials
We investigated the dielectric properties of typical embalming materials used in ancient Egypt in the THz frequency range. In addition, we evaluated the potential to identify these materials based on a principal component analysis of the spectroscopic data. Based on this, we estimated the composition of two unknown ancient bandages of mummified bodies
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