Calix[n]arene derivatives for gas storage

Abstract only availableThe calix[n]arenes are versatile inclusion compounds (Scheme 1) comprise of cyclic, polyphenolic compounds that can be tailored synthetically by altering X, Y, R and n. In solid state, we found simple calixarenes are quite interesting for example separation of hydrogen from mixture of gases so our attention turned into the closely related calixarenes for sorption studies. With this little back ground on calixarenes and their uses in solid state, we designed and synthesized tert-butylsulfonylcalix[4]arene and Tetra-p-tert-butyl-tetramethoxysulfonylcalix[4]arene from tert-butylthiacalix[4]arene by oxidizing in the presence H2O2 or NaBO3 in exceptional yield. Furthermore, asymmetric bridging of two calix[4]arene molecules to form a calixarene tubes with a larger and easily accessible cavity was also attempted to synthesize. Finally, H1NMR spectral and X- ray crystallographic modeling studies was done to reveal the conformational characteristics of the synthesized compounds.Stevens' Chemistry Progra

Demonstrate the removal efficiency and capacity of MOF materials for krypton recovery

Metal organic framework materials (MOFs) were developed and tested in support of the U.S. Department of Energy Office of Nuclear Energy, Fuel Cycle Technology Separations and Waste Forms Campaign. Specifically, materials are being developed for the removal of xenon (Xe) and krypton (Kr) from gaseous products of nuclear fuel reprocessing unit operations. Two metal organic framework structures were investigated in greater detail to demonstrate the removal efficiency and capacity of MOF materials for krypton recovery. Our two bed breakthrough measurements on NiDOBDC and FMOFCu indicate these materials can capture and separate parts per million levels of Xe and Kr from air. The removal efficiency and adsorption capacity for Kr on these two MOFs were further increased upon removal of Xe upfront

Unusually long cooperative chain of seven hydrogen bonds. An alternative packing type for symmetrical phenols

Conformational flexibility in a symmetrical tris-phenol leads to close packed structures that are also characterised by an extended though finite cooperative chain of hydrogen bonds

Initial proof-of-principle for near room temperature Xe and Kr separation from air with MOFs

Materials were developed and tested in support of the U.S. Department of Energy, Office of Nuclear Energy, Fuel Cycle Technology Separations and Waste Forms Campaign. Specifically, materials are being developed for the removal of Xenon and krypton from gaseous products of nuclear fuel reprocessing unit operations. During FY 2012, Three Metal organic framework (MOF) structures were investigated in greater detail for the removal and storage of Xe and Kr from air at room temperature. Our breakthrough measurements on Nickel based MOF could capture and separate parts per million levels of Xe from Air (40 ppm Kr, 78% N2, 21% O2, 0.9% Ar, 0.03% CO2). Similarly, the selectivity can be changed from Xe > Kr to Xe < Kr simply by changing the temperature in another MOF. Also for the first time we estimated the cost of the metal organic frameworks in bulk

Advances in Lymphatic Imaging and Drug Delivery

Cancer remains the second leading cause of death after heart disease in the US. While metastasized cancers such as breast, prostate, and colon are incurable, before their distant spread, these diseases will have invaded the lymphatic system as a first step in their progression. Hence, proper evaluation of the disease state of the lymphatics which drain a tumor site is crucial to staging and the formation of a treatment plan. Current lymphatic imaging modalities with visible dyes and radionucleotide tracers offer limited sensitivity and poor resolution; however, newer tools using nanocarriers, quantum dots, and magnetic resonance imaging promise to vastly improve the staging of lymphatic spread without needless biopsies. Concurrent with the improvement of lymphatic imaging agents, has been the development of drug carriers that can localize chemotherapy to the lymphatic system, thus improving the treatment of localized disease while minimizing the exposure of healthy organs to cytotoxic drugs. This review will focus on the use of various nanoparticulate and polymeric systems that have been developed for imaging and drug delivery to the lymph system, how these new devices improve upon current technologies, and where further improvement is needed

Fluorocarbon adsorption in hierarchical porous frameworks

Metal-organic frameworks comprise an important class of solid-state materials and have potential for many emerging applications such as energy storage, separation, catalysis and bio-medical. Here we report the adsorption behaviour of a series of fluorocarbon derivatives on a set of microporous and hierarchical mesoporous frameworks. The microporous frameworks show a saturation uptake capacity for dichlorodifluoromethane of &#62;4 mmol g-1 at a very low relative saturation pressure (P/Po) of 0.02. In contrast, the mesoporous framework shows an exceptionally high uptake capacity reaching &#62;14 mmol g-1 at P/Poof 0.4. Adsorption affinity in terms of mass loading and isosteric heats of adsorption is found to generally correlate with the polarizability and boiling point of the refrigerant, with dichlorodifluoromethane &#62; chlorodifluoromethane &#62; chlorotrifluoromethane &#62; tetrafluoromethane &#62; methane. These results suggest the possibility of exploiting these sorbents for separation of azeotropic mixtures of fluorocarbons and use in eco-friendly fluorocarbon-based adsorption cooling

An ortho­rhom­bic polymorph of pyrazino­[2,3-f][1,10]phenanthroline-2,3-dicarbonitrile

The title compound, C16H6N6, is a polymorph of the previously reported structure [Kozlov & Goldberg (2008 ▶). Acta Cryst. C64, o498–o501]. Unlike the previously reported monoclinic polymorph (space group P21/c, Z = 8), the title compound reveals ortho­rhom­bic symmetry (space group Pnma, Z = 4). The mol­ecule shows crystallographic mirror symmetry, while the previously reported structure exhibits two independent mol­ecules per asymmetric unit. In the title compound, adjacent mol­ecules are essentially parallel along the c axis and tend to be vertical along the b axis with dihedral angles of 72.02 (6)°. However, in the reported polymorph, the entire crystal structure shows an anti­parallel arrangement of adjacent columns related by inversion centers and the two independent mol­ecules are nearly parallel with a dihedral angle of 2.48 (6)°

Pillared two-dimensional metal-organic frameworks based on a lower-rim acid appended calix[4]arene

Solvothermal reactions of the lower-rim functionalized diacid calix[4]arene 25,27-bis(methoxycarboxylic acid)-26,28-dihydroxy-4-tert-butylcalix[4]arene (LH₂) with Zn(NO₃)₂•6H₂O and the dipyridyl ligands 4,4/-bipyridyl (4,4/-bipy), 1,2-di(4-pyridyl)ethylene (DPE) or 4,4/-azopyridyl (4,4/-azopy) afforded a series of 2-D structures of the formulae {[Zn(4,4/-bipy)(L)]•2¼DEF}n (1), {[Zn₂(L)(DPE)]•DEF}n (2) and {[Zn(OH₂)₂(L)(4,4/-azopy)]•DEF}n (3) (DEF = diethylformamide)