A novel Cu(I)-based two-dimensional (2D, 4 4 net) metal−organic framework (MOF) [Cu(L)(I)] 2n •2nDMF• nMeCN (1); L = 4′-(4-methoxyphenyl)-4,2′:6′,4″-terpyridine; DMF = N,N-dimethylformamide, MeCN = acetonitrile) has been synthesized and found to behave as a colorimetric detector for the widest variety of small molecules such as different solvents, halobenzenes, N-heterocycles, amine, and nitroaromatic explosives all in vapor phase through a single crystal to single crystal (SCSC) transformation. The 2D 4 4 nets are interdigitated with each other to form a supramolecular 3D MOF having 1D pore. The interdigitated layers are stabilized by π•••π interactions and CH•••π interactions and provide extreme stability up to 380 °C. Interestingly, all guest exchange and encapsulation processes are reversible without loss of structural integrity. Positions of the guest molecules in the host−guest complex have been identified from the crystal structure and found to involve weak interactions with the framework. Notably, this is the first time for a report of any material which encapsulates such a large number of small molecules in the vapor phase from different chemical classes in SCSC fashion with visible color changes. Tests confirm the selectivity toward most polar molecule in a class. In the presence of guest molecules, the MOF exhibits a blue shift in fluorescence emission spectra and the extent of the blue shift is appreciably high. It also shows high selectivity toward diethylamine (dea) among N-heterocycles, amine, and highly explosive trinitrophenol (TNP) among nitroaromatic explosives as revealed from concurrent luminescence quenching in solution. Finally, the MOF represents one of the best hosts reported so far having extreme stability and selectivity and meets the benchmark of reversibility for material applications.
The dermoid cyst is an uncommon clinicopathological lesion of developmental origin. The term dermoid cyst is used to describe 3 cysts that are closely related histologically: dermoid cyst, epidermoid cyst, and teratoma. Epidermoid and dermoid cysts are benign nature, which may occur anywhere in the body, but most predominantly in the ovary and scrotal regions. Only about 7% are found in the head and neck. The occurrence of such cysts in the oral cavity is extremely rare, with approximately 1.6% located in this area. The floor of the mouth is one of the most commonly affected area, however, these cysts can also be found in the tongue, lips, buccal mucosa and jaw bones. There is always a difficulty of making a correct diagnosis of these lesions with clinical examinations and conventional radiography. To achieve a diagnosis and to develop correct surgical strategy specialized imaging examinations such as ultrasonography (US), computed tomography (CT), Magnetic Resonance Imaging (MRI) and histopathological examination should be carried out. Treatment comprises total surgical excision the approach remains dictated logically by the cyst's location. Ample understanding and vigilance about this slow growing painless mass is essential not only because of the symptoms it produces but also due to its malignant potential. When dermoid cysts occur on the floor of the mouth, they may enlarge to such an extent that they can interfere with deglutition and produce respiratory obstruction. Early diagnosis and treatment are essential for these cystic entities.
The ligand HL has been built by linking an imidazole moiety to the 5-position of isophthalic acid. It forms two types of porous frameworks, {[Zn(L)]·2DMF·2HO} (1) and {[(CH)NH][Zn(L)(HO)PO]·2DMF} (2). 1 is a porous neutral framework and has rtl rutile 3,6-conn topology, while 2 is an organo-metallophosphate anionic porous framework with double-walled hexagonal channels. Framework 1' (desolvated) exhibits moderate CO adsorption (58 cc g at 273 K, 1 bar), whereas 2' (desolvated) shows a microporous nature with a high adsorption of CO (111.7 cc g or 22 wt % at 273 K, 1 bar). Interestingly, this adsorbed CO could be converted very efficiently to cyclic carbonates under mild conditions using 2' as the catalyst in the presence of tetrabutylammonium bromide as the cocatalyst. The presence of open metal sites in 2' makes it an efficient heterogeneous catalyst for solvent-free three-component Strecker reaction using various aldehydes/ketones together with amines and trimethylsilyl cyanide in high yields at room temperature. The straightforward experimental and product isolation procedure along with easy recovery and reusability of the catalyst provided an attractive route for the synthesis of α-amino nitriles.
Two 2D coordination polymers have been synthesized by employing V-shaped flexible terpyridine-based ligand L [L = 4′-(4-methoxyphenyl)-4,2′:6′,4′′-terpyridine] as linker and M II (M = Co II , Fe II ) as nodes. Structural analysis of both complexes revealed the formation of a rare [4+4] metallocyclic unit. The extension of these cyclic units into two dimensions gives rise to an interdigitated 2D sheet structure in which the methoxy group of the ligand is oriented above and below the sheet IntroductionOver the past few decades, coordination polymers (CPs) have attracted extensive research interest owing to the variety of their architectures and intriguing topologies [1] as well as potential applications. [2] Apart from their structural role in supporting solid-state architectures, the metal ions in CPs are the source of some useful physical properties, for example, the blocking of magnetization, and molecules having such properties are known as single-molecule magnets (SMMs). [3,4] SMMs are known for their potential applications in high-density data storage, quantum computing, and molecular spintronics. [3] Recently, there has been particular interest in molecular systems with only one spin carrier, large magnetic anisotropy, no intermetallic interactions, and properties similar to SMMs called single-ion magnets (SIMs). The most interesting feature of SIMs [5] is the possibility of tuning their magnetic anisotropy through the regulation of the coordination number and ligand field. In parallel with the extensive study of lanthanide-based SIMs, [5] significant effort has also been devoted to the research of transition-metal-based SIMs. [6][7][8] A common feature of all the reported transition-metal-based SIMs is the low coordination number of the metal centers, for which the single-ion anisotropy is enhanced due to unrestricted orbital angular momentum by limiting the coordination number of the metal ion. [9] Among 3d SIMs, Co II -based complexes are the most interesting because of their non-integer spin ground state, [10] which reduces the probability of quantum tunneling of magnetization (QTM). [11] Recently, a few octahedral Co II complexes have been [a] for their helpful scientific discussions.
A Cu(ii) metal-organic framework, {[Cu(L)(HO)]·(5DMF)(4HO)} (1), has been synthesized using an angular tetracarboxylic acid ligand (H4L) incorporating both trifluoromethyl (-CF) and amine (-NH) groups. Notably, the framework possesses high water and thermal stability. At atmospheric pressure, the activated framework 1' exhibits substantially high amounts of CO (35.5 and 20.8 wt% at 273 and 298 K respectively) and H (1.72 wt% at 77 K) adsorption. Also, 1' exhibits excellent catalytic activity for the condensation-cyclization reaction between 2-benzoyl pyridine and different benzylamines via oxidative amination of the C(sp)-H bond to form 1,3-diarylated imidazo[1,5-a]pyridines under mild aerobic conditions. In addition to this, 1' shows excellent heterogeneous catalytic activity in Biginelli reactions. The solid catalyst could be recycled several times without significant loss in the catalytic activities.
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