Tetrakis- -calix arenes

The silver(I) complexes with the tetrakis(methylthio)tetrathiafulvalene ligand have been reported, the nitrate salt presents a 3D structure with an unprecedented 4.16-net porous inorganic layer of silver nitrate,1160 the triflate salt presents a two interwoven polymeric chain structure.1161 The latter behaves as a semiconductor when doped with iodine. With a similar ligand, 2,5-bis-(5,5,-bis(methylthio)-l,3,-dithiol-2 -ylidene)-l,3,4,6-tetrathiapentalene, a 3D supramolecular network is constructed via coordination bonds and S"-S contacts. The iodine-doped compound is highly conductive.1162 (Methylthio)methyl-substituted calix[4]arenes have been used as silver-selective chemically modified field effect transistors and as potential extractants for Ag1.1163,1164... 

C80H56C14JN4O12 CPCHA (25,26,27,28-telrahydroxy-5,11,17,23-tetrakis(A -p-chlorophenyl)calix[4]arene-p,p, p", p "-tetrakis(amino-bis(acetohydroxamic acid))) Extraction Th, U, Zr 149-151... 

This tetrakis-urea was expected to self-assemble in apolar media by hydrogen bond formation between urea moieties of two different units. The analogous behavior of calix[4]arene tetrakis-ureas is well documented [75], but, in contrast to the corresponding calix[4]arene capsules, those deriving from 31 would feature hydrogen bond donor sites within the cavity (Fig. 5). 

The term calix[n]arenes indicates a class of phenolic metacyclophanes derived from the condensation of phenols and aldehydes. The name was coined by Gutsche and derives from the Latin calix because of the vase-like structure that these macrocycles assume when all the aromatic rings are oriented in the same direction.1 The bracketed number indicates the number of aromatic rings and hence defines the size of the macrocycle. To identify the phenol from which the calixarene is derived, the para substituent is designated by name. Thus the cyclic tetramer derived from p-f-butylphenol and formaldehyde is named p-f-butylcalix[4]arene, or with a more systematic but still simplified nomenclature proposed by Gutsche and used in this chapter 5,11,17,23-Te trakis( 1,1 -dimethylethyl)-25,26,27,28-tetrahydroxy calix [4] arene, 1 (Scheme 7.1). The systematic name reported by Chemical Abstracts is pentacyclo[19.3.1.13,7.19 13.115 19]octacosa-l (25),3,5,7(28),9,11,13(27),15,17, 19(26), 21,23-dodecaene-25,26,27,28-tetrol-5,l l,17,23-tetrakis(l, 1 -dimethylethyl). 

Tetrakis(3-Diphenylphospbinoxide-acetamide-propoxy)-p-t-butyl calix[4]arene... 

An alternative method for preparing tetrakis(3-aminoalkoxy)-p-t-butyl calix[4]arene was also provided by the author as illustrated in Eq.l ... 

Beginning with 4-nitro calix[4]arene, alkoxy derivatives of tetrakis-4-diphenylphosphinoxide-propylamide)-calix[4]arene, (I), have been prepared and are described (2,3). 

The macrocyclic diphosphonite 25 was obtained in good yield from phenylbis-(diethylamino)phosphine. A new calix[4]arene tetrakis(dimethylphosphinite) (26) has been synthesised and its X-ray crystal structure determined. Both in... 

Among the four conformations of the calix[4]arenes, the least often encountered is the 1,2-alternate. The first reported example is the complex obtained by treatment of the tetramethyl ether of 4 with AlMe3. More recent examples, include the tetraethyl ether 94a, the tetrakis(2-pyridylmethyl) ether 94b, the dimethyl ether diphosphate 94c of bridged ether... 

The p-quinonemethide route, introduced in the late 1980s,starts with the reaction of a p-H-calixarene with HCHO and a dialkylamine to produce a Mannich base, followed by methylation of the Mannich base to give the quaternary salt, and treatment with two equivalents of a nucleophile to produce a p-CH2Nu-calixarene, as illustrated by the conversion of 194 to 196. The Mannich reaction appears to occur with greater facility with the fully hydroxylated calixarenes than with their partial ethers, perhaps a consequence of the greater acidity of the former. For example, 4 reacts smoothly at room temperature (24 h) to afford the tetrakis(dimethylaminomethyl)calix[4]arene, whereas its A,C-dimethyl ether fails to react under these conditions and requires 66 h reaction time in refluxing dioxane. The A,C-dibenzoate and the A,C-diallyl ether of 4 both fail to undergo the Mannich reaction even at 140°C. ... 

On the basis of the catalytic roles of calix[4]arene derived model 18-[Zn"]2 (99JOC3896) and cis-diaqua Cu complexes for cleavage of phosphate diesters, Reinhoudt designed a calix[4]arene derivative 66-[Cu ]2 functionalized with two ds-diaqua Cu° centers at the distal positions of the upper rim as a model for dinuclear metalloenzymes that catalyze chemical transformations of phosphate esters. It was synthesized from Cu(C104)2 and 5,17-bis(bis(l-methylimidazol-2-yl)hydroxy-methyl)-25,26,27,28-tetrakis(2-ethoxyethoxy)calix[4]arene which was conveniently obtained from the precursor diester and lithiated 1-methyl-imidazole. In this model, the two Cu° centers are well organized on the calixarene scaffold for performing S5mergistic action. 

BSA and then polymerized by both cationic and radical initiators before liberating the free phenolic groups by cleavage with acid. A number of calixarene trimethylsilyl ethers have been prepared from the phenols using BSA. Calix[4]arene has been converted into a mixture of tris- and tetrakis(trimethylsilyl) ethers by heating the phenol with BSA in acetonitrile. ... 

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