Nonplanar aromatic compounds. 8.1 synthesis, crystal structures, and aromaticity investigations of the 1,n-dioxa[n](2,7)pyrenophanes. How does bending affect the cyclic π-electron delocalization of the pyrene system?
A series of 1,n-dioxa[n](2,7)pyrenophanes (n = 7-12) with increasingly nonplanar pyrene moieties was synthesized by a 9-10 step sequence starting from 5-hydroxyisophthalic acid. The crystal structure of each member of this series was determined crystallographically. Several spectroscopic properties were found to vary with the extent of the nonplanarity of the pyrene unit. The way in which the distortion from planarity of the pyrene system influences its π-electron delocalization was investigated by using two quantitative descriptors of aromaticity based on geometry (HOMA) and magnetism (magnetic susceptibility and NICS). Both methods suggest that the aromaticity of the pyrene moiety is diminished only slightly upon increasing the bend angle θ from 0° to 109.2°.
Bodwell, Graham J.,Bridson, John N.,Cyranski, Michal K.,Kennedy, Jason W. J.,Krygowski, Tadeusz M.,Mannion, Michael R.,Miller, David O.
Synthesis and antiproliferative activity of novel steroidal dendrimer conjugates
We describe the synthesis of steroidal dendrimer conjugates of first and second generation with tetramethylene core and 5-hydroxy-isophtalic acid dimethyl ester as branching unit modified to incorporate ethynylestradiol or 17α-estradiol as terminal units. The steroidal dendrimer conjugates, the free drug (steroids) and dendrimer were tested against a panel of cancer cell lines (CEM, MCF7, HeLa) and normal human fibroblast (BJ). The steroidal dendrimer conjugates of first generation exhibited cytotoxic activity and induced apoptosis in chronic leukemia (CEM) as resultant activation of caspase cascade which is mainly provoked in G2/M arrested cells.
Maga?a-Vergara, Nancy E.,Rárová, Lucie,Soto-Castro, Delia,Farfán, Norberto,Strnad, Miroslav,Santillan, Rosa
p. 1254 - 1262
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Ligand flexibility and framework rearrangement in a new family of porous metal-organic frameworks
Ligand flexibility permits framework rearrangement upon evacuation and gas uptake in a new family of porous MOFs. The Royal Society of Chemistry.
Hawxwell, Samuel M.,Espallargas, Guillermo Minguez,Bradshaw, Darren,Rosseinsky, Matthew J.,Prior, Timothy J.,Florence, Alastair J.,Van De Streek, Jacco,Brammer, Lee
p. 1532 - 1534
(2008/02/03)
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