97431-84-0Relevant academic research and scientific papers
Self-complementary [2]catenanes and their related [3]catenanes
Cabezon, Beatriz,Cao, Jianguo,Raymo, Francisco M.,Stoddart, J. Fraser,White, Andrew J. P.,Williams, David J.
, p. 2262 - 2273 (2007/10/03)
Three [3]catenanes with cavities large enough to accommodate aromatic guests have been designed and synthesized (yields = 5-20%) by means of kinetically controlled self-assembly processes. The X-ray structural analysis of one of three [3]catenanes confirmed the presence of a rectangular cavity (dimensions = 7 ×11 A) lined by π-electron-rich recognition sites and hydro-gen-bond acceptor groups. In spite of their apparently ideal recognition features, none of these [3]catenanes bind guests incorporating a π-electron-deficient bipyridinium unit. However, the template-directed syntheses of the [3]catenanes also produce, in yields of 2-23%, [2]catenanes incorporating a l,5-dioxynaphtho[38]crown-10 inter-locked with a bipyridinium-based tetracationic cyclophane. The X-ray structural analyses of two of these [2]catenanes revealed that a combination of [π...π] and [C-H...π] interactions is responsible for the formation of supramolecular homodimers in the solid state. 1H NMR spectroscopic investigations of the four [2]catenanes demonstrated that supramolecular homodimers are also formed (Ka= 17-31M-1, T= 185 K) in (CD3)2CO solutions. Dynamic 1H NMR spectroscopy revealed that the 1,5-dioxynaphtho[38]crown-10 and tetracationic cyclophane components in the four [2]catenanes and in the three [3]catenanes circumrotate (ΔGC? = 9-14 kcal mol-1) through each other's cavity in (CD3)2CO. Similarly, the 1,5-dioxynaphthalene and the bipyridinium ring systems rotate (ΔGc? =10-14 kcalmol-1) about their [O...O] and [N ... N] axes, respectively, in solution.
Quantitative Structure-Activity Relationship Analysis of Cation-Substituted Polyaromatic Compounds as Potentiators (Amplifiers) of Bleomycin-Mediated Degradation of DNA
Strekowski, Lucjan,Wilson, W. David,Mokrosz, Jerzy L.,Mokrosz, Maria J.,Harden, Donald B.,et al.
, p. 580 - 588 (2007/10/02)
A set of 21 polyheteroaromatic compounds substituted with flexible cationic groups and of similar molecular size has been analyzed for binding with DNA and for effects on the bleomycin-mediated degradation of the DNA double helix.Increases in apparent rat
Solid-State Inclusion Compounds of New Host Macrocycles with Uncharged Organic Molecules. Host Synthesis, Inclusion Properties, and X-ray Crystal Structure of an Inclusion Compound with 1-Propanol
Weber, Edwin,Josel, Hans-Peter,Puff, Heinrich,Franken, Sybille
, p. 3125 - 3132 (2007/10/02)
A series of organic macrocycles composed of a systematically varied combination of ethano, propano, benzeno, pyridino,and analogous groups, mainly ether-linked (see Chart I), are reported, and their abilities to function as solid-state inclusion hosts are studied.It is found that 3-5, 11-13, 18b, and 21 form crystalline inclusion compounds with a number of low-molecular-weight alcohols such as methanol, ethanol, 1- and 2-propanol, 1-butanol, ethylene glycol, and/or with dimethylformamide and acetonitrile as CH-acidic guests.The observed inclusion selectivities and thestoichiometries of the various host-guest compounds are discussed showing that by and large both chemical and steric host-guest fits apply in the formation of the aggregates.The crystal structure of the inclusion compound of the bipyridino host 11 with 1-propanol (1:1) has been determined from single-crystal X-ray diffraction.There are eight host and guest molecules in each unit cell of dimension a = 2665.2 pm, b = 813.8 pm, c = 2667.4 pm, β = 105.61 deg; space group C2/c; R = 0.088 for 2884 unique reflections.The host macrocycle shows a hollow-type conformation with the 1-propanol molecule coordinated via a moderately stable H-bond to one of the bipyridine nitrogens (O...N = 300 pm).The packing diagram characterizes the host-guest topology largely as a channel-like clathrate (actually "tubulato-coordinatoclathrate").A number of general conclusions that will facilitate the future design of selectively binding hosts for solid-state inclusion are given.
