All wrapped up: An easy, highly selective separation of C70 and the higher fullerenes has been achieved by solid–liquid extraction with a 2‐ureido‐4‐[1H]‐pyrimidinone‐based scaffold which wraps around the guest as a dimeric capsule (see picture), thereby solubilizing it in THF. Acidification disrupts the hydrogen‐bonding network and allows easy recovery of the guest and recycling of the receptor without chromatography or tedious procedures.

Protein p53 is a transcription factor crucial for cell cycle and genome integrity. It is able to induce both cell arrest when DNA is damaged and the expression of DNA repair machinery. When the damage is irreversible, it triggers apoptosis. Indeed, the protein, which is a homotetramer, is mutated in most human cancers. For instance, the inherited mutation p53-R337H results in destabilization of the tetramer and, consequently, leads to an organism prone to tumor setup. We describe herein a rational designed molecule capable of holding together the four monomers of the mutated p53-R337H protein, recovering the tetramer integrity as in the wild-type structure. Two ligand molecules, based on a conical calix[4]arene with four cationic guanidiniomethyl groups at the wider edge (upper rim) and hydrophobic loops at the narrower edge (lower rim), fit nicely and cooperatively into the hydrophobic clefts between two of the monomers at each side of the protein and keep the tetrameric structure, like molecular templates, by both ion-pair and hydrophobic interactions. We found a good agreement between the structure of the complex and the nature of the interactions involved by a combination of theory (molecular dynamics) and experiments (circular dichroism, differential scanning calorimetry and 1 H saturation transfer difference NMR). molecular recognition ͉ multivalent calix[4]arene ligands ͉ oligoprotein stabilization ͉ protein-protein interactions

The Bingel-Hirsch reactions on non-isolated pentagon rule (non-IPR) Gd(3)N@C(2n) (2n = 82, 84) are studied. Computational results show that the two metallofullerenes display similar reactivity according to their related topologies. Long C-C bonds with large pyramidalization angles lead to the most stable adducts, the [5,6] bonds in the adjacent pentagon pair being especially favored. The lesser regioselectivity observed for Gd(3)N@C(82) is probably due to the activation of some C-C bonds by means of the metal cluster.

Potassium channels are among the core functional elements of life because they underpin essential cellular functions including excitability, homeostasis, and secretion. We present here a series of multivalent calix [

The reactions of phosphido complexes [Nb(eta(5)-C(5)H(4)SiMe(3))(2)(L)(PPh(2))] [L = CO (1), CNxylyl (2), CNCy (3)] with alkynes have been carried out. The new diphenylphosphinoalkenyl niobocene complexes [Nb(eta(5)-C(5)H(4)SiMe(3))(2)(eta(1)-C-C(CO(2)CH(3))=C(R)PPh(2))(CO)] [R = H (4), CH(3) (5)] and [Nb(eta(5)-C(5)H(4)SiMe(3))(2)(eta(1)-C-C(CO(2)R)=C(CO(2)R)PPh(2))(CO)] [R = CH(3), (6), R = (t)Bu, (7)] were successfully synthesized by the reaction of with methyl propiolate (HC[triple bond]CCO(2)CH(3)) or methyl 2-butynoate (CH(3)C[triple bond]CCO(2)CH(3)) and dimethyl 2-butynedioate [(CH(3) O(2)C)C[triple bond]C(CO(2)CH(3))] or di(tert-butyl) 2-butynedioate [((t)BuO(2)C)C[triple bond]C(CO(2)(t)Bu)], respectively. However, reaction was not observed with more electron-rich alkynes. Complex reacted with methyl propiolate, methyl 2-butynoate (MeC[triple bond]CCO(2)Me) or di(tert-butyl) 2-butynedioate to give surprising new heteroniobacycle complexes [Nb(eta(5)-C(5)H(4)SiMe(3))(2)(eta(1)-C-C(=NXylyl)C(R(1))=C(R(2))PPh(2)-kappa(1)-P)] [R(1) = H, R(2) = CO(2)Me (8); R(1) = Me, R(2) = CO(2)Me (9); R(1) = CO(2)(t)Bu, R(2) = CO(2)(t)Bu (10)]. Finally, the phosphido complexes and reacted with phenylacetylene (PhC[triple bond]CH) to give new diphenylphosphinoalkenyl niobocene derivatives [Nb(eta(5)-C(5)H(4)SiMe(3))(2)(eta(1)-C-C(C(6)H(5))=C(H)PPh(2))(CNR)] [R = xylyl (11), Cy (12)]. All of these compounds were characterized by NMR spectroscopy and the molecular structure of was determined by single-crystal X-ray diffraction studies. Theoretical studies were also carried out by means of density functional theory (DFT) calculations on the insertions of alkynes into the Nb-P bond in the phosphido niobocenes.

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Fullerenes C60, C70, and C84 may be readily encaged within a hydrogen-bonded dimeric capsule, based on two concave cyclotriveratrylene (CTV) scaffolds each bearing three self-complementary 2-ureido-4-[1H]-pyrimidinone (UPy) subunits. We herein report NMR and CD studies-complemented by dispersion-corrected density functional theory calculations-aiming to characterize such capsulefullerene complexes both structurally and energetically. Six fullerenes are considered: in agreement with experiment, calculations find that encapsulation is most favorable for C84 (on a par with C90), and follows the trend C60

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