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Basket-shape

The cryptophane is typical of the chiral resolution of methane derivatives (eg, CHFClBr) (146) and the basket-shaped host of Figure 23d exhibits extremely high enantioselectivity for various peptides (144). [Pg.187]

FIGURE 35 Copper vessel. Basket-shaped copper vessel from the Cave of the Treasure, Nahal Mishmar, Israel. Copper, one of the earliest used metals, has been one of the most important materials in the development of materials technology. Masses of native copper were being pounded into tools and ornaments as early as the tenth millennium b.c.e. Because of the relative ease with which it is recovered from its ores, its remarkable physical properties (high ductility, malleability, and thermal conductivity) and its resistance to corrosion, copper has been among the major metals in terms of the quantities consumed. [Pg.193]

As a first step toward a dopamine-jS-hydroxylase mimic, basket-shaped receptor 17 was functionalized with two sets of bis-[2-(3,5-dimethyl-l-pyra-zolyl)ethyl]amine ligands to give compound 35 (see Scheme 5). Reaction of 35 with Cu(C104,)2-6H20 yielded complex 36 which was fully characterized [39], Ligand system 35 binds dopamine derivative 37 and phloroglucinol (1,3,5-trihydroxybenzene) with association constants of = 60 and 3500 respectively. The affinity of the Cu(I) analogon of 36 for 37 was very similar to that of 36 itself and amounted to Ka = 60 M L Resorcinol is bound in the cavity of the Cu(I) complex with a Xj-value of 2(XX) M". ... [Pg.54]

Smeets, J.W.H., van Dalen, L., Kaats-Richters, V.E.M. and Nolte, R.J.M. (1990) Functionalized basket-shaped hosts. Synthesis and complexation studies with (alkali) metal and ammonium and diammonium ions. J. Org. Chem., 55, 454—461. [Pg.162]

Figure 4. The synthetic strategy for basket-shaped molecules 12 led to a simple one-step synthesis of the tetramethoxy-substituted [2]catenane 11. Figure 4. The synthetic strategy for basket-shaped molecules 12 led to a simple one-step synthesis of the tetramethoxy-substituted [2]catenane 11.
Scheme 6 Schematic representation of the synthetic approach to basket-shaped molecules with... Scheme 6 Schematic representation of the synthetic approach to basket-shaped molecules with...
Calix[4]arenes are characterized by a three-dimensional basket shape, the internal volume being around 10 nm3. Calixarenes exist in different chemical conformations because rotation around the methylene bridge is possible. In calix[4]arene, four conformations are possible cone, partial cone, 1,2-altemate, and 1,3-altemate. These four conformations are in dynamic equilibrium. Conformations can be locked, for instance, by placing a bulkier substituent than the ethyl group on the lower (or narrow) rim, this chain prevents the benzene units from rotating inside the calixarene cavity. [Pg.202]

FIGURE 6. Comparison of the closed cubane-like core unit (a) of [(Et2S)3 Cu4(p3-I)4 ] 1 with the flower-basket-shaped core unit (b) of [(Me2S)3 Cu4(p,-I)4 ] 4. [Pg.97]

A Newman-Kwart rearrangement of the O-thiocarbamoy I derivative of a thiacalix[4]arene results in the synthesis of thiacalix[2]thianthrenes 69. The two thianthrene units are linked by two sulfur bridges producing a basket-shaped molecule <07TL5401>. Treatment with... [Pg.425]

Bis-macrocycles two macrocycles joined together Calixarenes basket-shaped macrocycles with phenyl backbones... [Pg.2418]

A basket-shaped, macrotricyclic cyclophane receptor with a deep cavity (Figure 72) has been utilized by Meric et al. for binding quaternary ammonium cations [98]. Association constants of the order of 10 -10 M were reported. [Pg.77]

Figure 72 A basket-shaped macrotricyclic receptor for the complexation of quaternary ammonium cations [98]... Figure 72 A basket-shaped macrotricyclic receptor for the complexation of quaternary ammonium cations [98]...
Myoepithelia Basket-shaped, mononuclear cells surrounding the acini of exocrine glands have cytoplasmic fibrils resembling smooth muscle derived from ectoderm rather than mesoderm. Contraction stimulated by hormones (e.g., oxytocin) and presumably by autonomic nerves may have noncontractile functions such as pressure transduction in the renal cortex. Contraction to expel contents of exocrine glands (salivary, sweat, mammary) form the dilator muscle of the iris may be the pressure transducers in juxtaglomerular cells. [Pg.455]

A basket-shaped host that is a crown ether containing a bi-cyclic urea structure (7.6) (where R is phenyl) has been used to bind the herbicide Paraquat analogue (7.7) (where the anion is hexafluorophosphate) and some polymeric derivatives of it with iPup to 57,000.63 Even stronger binding with a Kof 7 million has been obtained with a cyclic urea porphyrin.64... [Pg.180]

Figure 14. Stereoviews of the defensin dimer crystal structure [coordinates courtesy of D. Eisenberg (160)7. (A) Perspective that shows the basket shape of the molecule and the van der Waals surfaces of the charged side chains. In some cases, side-chain atom positions are not defined and have been placed in a low-energy conformation. (B) Perspective that shows the beta-sheets within each dimer and the subunit interaction. Figure 14. Stereoviews of the defensin dimer crystal structure [coordinates courtesy of D. Eisenberg (160)7. (A) Perspective that shows the basket shape of the molecule and the van der Waals surfaces of the charged side chains. In some cases, side-chain atom positions are not defined and have been placed in a low-energy conformation. (B) Perspective that shows the beta-sheets within each dimer and the subunit interaction.
Vogtle and Wambach recently for the first time described basket-shaped host molecules of the types 106a, b and 107 which apart from a 30-membered ring as the wall contain a floor-plate , which cannot dive through the 30-membered basket-... [Pg.166]

Fabrication needs also include the ability to combine organic and inorganic nanoparticles into hybrid materials. For example, organic clathrates, binders, and basket-shaped molecules - such as block copolymers and triblock polymers - may be combined with inorganic oxides, polyoxometaUates, and chemically aggressive porous materials to form useful hybrids. This is important in the development of countermeasures that can select, detect, and decontaminate a wide range of toxic materials. [Pg.106]


See other pages where Basket-shape is mentioned: [Pg.187]    [Pg.985]    [Pg.13]    [Pg.55]    [Pg.162]    [Pg.179]    [Pg.180]    [Pg.187]    [Pg.182]    [Pg.70]    [Pg.96]    [Pg.126]    [Pg.187]    [Pg.117]    [Pg.464]    [Pg.226]    [Pg.271]    [Pg.28]    [Pg.29]    [Pg.985]    [Pg.884]    [Pg.280]    [Pg.814]    [Pg.118]    [Pg.584]    [Pg.68]    [Pg.465]   
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Basket-shaped molecules

Shaping the Baskets Conformations of Calixarenes

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