By varying the reaction conditions, the reaction of [W(eg)3] (eg = 1,2-ethanediolato) with p-tert-butylcalix[n]areneHn (n = 6 or 8) in refluxing toluene affords, following work-up, a number of products which have been fully characterized. From the reaction of p-tert-butylcalix[6]areneH6 with one or two equivalents of [W(eg)3], only the oxo-bridged complex {[W(eg)]2(μ-O)p-tert-butylcalix[6]arene...

A photoresponsive ion carrier based on calix[4]arene was synthesized for the control of Na+ flux across lipid bilayer membranes by visible light. Calix[4]arene was chosen as a basic skeleton of a photoresponsive ion carrier because its ether derivatives are known to act as Na+ ion carriers in lipid bilayer membranes. For the synthesis of a photoresponsive carrier, dimethylaminoazobenzene was in...

A photoresponsive ion carrier based on calix[4]arene was synthesized for the control of Na+ flux across lipid bilayer membranes by visible light. Calix[4]arene was chosen as a basic skeleton of a photoresponsive ion carrier because its ether derivatives are known to act as Na+ ion carriers in lipid bilayer membranes. For the synthesis of a photoresponsive carrier, dimethylaminoazobenzene was in...

Structural and mechanistic studies of the lithium diisopropylamide (LDA)-mediated anionic Fries rearrangements of aryl carbamates are described. Substituents at the meta position of the arene (H, OMe, F) and the dialkylamino moiety of the carbamate (Me(2)N, Et(2)N, and i-Pr(2)N) markedly influence the relative rates of ortholithiation and subsequent Fries rearrangement. Structural studies using...

The conductometric sensor based on 25,27-di-(5-thio-octyloxy)calix[4]arene-crown-6 was developed for the quantitative analysis of ammonium. The calixarene was immobilized on the surface of the planar interdigitated electrodes by attachment of its dialkyl sulfide groups to the surface of the gold electrodes. The intrinsic ability of the calixarene to capture ammonium was studied in the conductom...

The conformational behavior of monosubstituted tri-methylsilyle ethynyl Derivative of Cal ix[4]arene as a newgeneration of Caliarene was compared with tetra alkylated calyx[4]arene. The most important conformationalphenomena in these compounds which are pinched cone interconversion process were done by semi-empiricalmethod and ab initio calculations with Gaussian 98w programming.

The per-ipso-nitration of a TMPA-capped calix[6]arene has been achieved. The substitution of the six bulky tBu substituents for nitro groups has a strong impact on the behavior of the ligand during guest recognition. The complexation of the aza cap (by H(+) or Cu(+)) associated with the encapsulation of a guest triggers an induced-fit process leading to the loss of the cone conformation of the ...

Enantiopure cis-dihydrodiol bacterial metabolites of substituted benzene substrates were used as precursors, in a chemoenzymatic synthesis of the corresponding benzene oxides and of a substituted oxepine, via dihydrobenzene oxide intermediates. A rapid total racemization of the substituted benzene 2,3-oxides was found to have occurred, via their oxepine valence tautomers, in accord with predict...