325814-48-0

Upstream product

• 143406-35-3 25,27-dihydroxy-26,28-dipropoxycalix[4]arene 
• 157432-87-6 5,11,17,23-tetra-t-butyl-25,26,27,28-tetrahydroxycalix-4-arene 
• 248590-47-8 25,26,27,28-tetrakis(hydroxy)calix[4]arene 

Downstream Products

• 945554-43-8 11,23-dibromo-25,27-dibenzyloxy-26,28-bis(propyloxy)calix[4]arene 
• 910885-83-5 C₄₀H₄₄Br₂O₆ 
• 1038081-71-8 11,23-bis[5'-(4-hexadecyloxyphenyl)-2,2'-bithiophen-5-yl]-25,27-dihydroxy-26,28-dipropoxycalix[4]arene 
• 217454-83-6 5,17-bis(diphenylphosphonium)-25,26,27,28-tetrapropoxycalix[4]arene 

Relevant academic research and scientific papers

Novel biscalix[4]arene-based anion receptors

Novel biscalix[4]arene derivatives where two calixarene units are connected via one or two ureido bridges on the upper rim has been prepared. These compounds represent well preorganised cavities with interesting complexation abilities towards anions. The structure of bis-ureido derivative was proved by X-ray crystallography.

Lower-Rim-Modified Calix[4]arene-Pyrrolotetrathiafulvalene Molecular Tweezers

An approach for the lower rim modification of the calix[4]arene-based molecular tweezes with monopyrrolo-tetrathiafulvalene (MPTTF) arms attached to the upper rim of calixarenes is described. First, calixarene-MPTTF conjugates with free hydroxyl on the lower rim are synthesized using the Ullmann reaction, then hydroxyl groups are substituted by propargyl groups, which can be used for further modification by the click reaction. The new calixarene-TTF derivatives displayed reversible redox processes, as well as demonstrated binding affinity for electron-deficient molecular guests such as tetracyanoquinodimethane. The described synthetic approach will be used for the modular synthesis of molecular receptors tailored for specific applications.

Synthesis of calix[4]arene-cyclen conjugates

Novel calix[4]arene derivatives constrained in the cone or 1,3-alternate conformations, bearing one or two cyclen (1,4,7,10-tetraazacyclododecane) moieties directly connected to the upper rim, have been synthesized using Buchwald-Hartwig coupling reaction. The complexation ability and hydrolytic activities of selected Zn(II) complexes of these calixarenes were studied. Although the attempts to hydrolyze activated phosphodiester bonds were unsuccessful, the NMR titration experiments revealed binding affinity for chloride, acetate, and benzoate anions in defined stoichiometry.

Two structural types of 1,3-alternate tetrapropoxycalix[4]arene derivatives in the solid state

The solid state structures of seven tetrapropoxycalix[4]arene derivatives immobilised in a 1,3-alternate conformation were determined using single-crystal X-ray crystallography. The cavity shapes of investigated derivatives (upper rim unsubstituted, dista

Regioselective upper-rim functionalizations of calix[4]arene by diphenylphosphino groups

The regioselective upper-rim functionalization of calix[4]arene have been performed to prepare all the multisubstituted diphenylphosphine derivatives. In addition, the X-ray structures of 5,17-dibromo-11,23-bis(diphenylphosphino)-25,26,27,28-tetra-n-propoxycalix [4]arene and 5,11,17,23-tetrakis(diphenylphosphino)-25,26,27,28-tetra-i-propoxy-calix[4] arene have been determined. Regioselective functionalizations have been achieved using methods that involve appropriate choices of bases, alkyllithium-solvent systems, stoichiometry, and reaction times. A new and convenient method for selectively preparing derivitized calix[4]arenes at proximal positions in relative large scale quantity has been developed and involves a transesterification of the distal diester derivative into the proximal isomer.

Synthesis and inclusion properties of a upper-rim-connected biscalix[4]arene

The conformationally-immobile biscalix[4]arene was synthesized by connecting the upper rims with two spacers. It showed high inclusion ability and selectivity for quaternary ammonium ions. A comparison with reference compounds established that the enhanced selectivity is due to the cooperative action of two howl-shaped calix[4]arenes.

Upper-rim urea-derivatized calix[4]arenes as neutral receptors for monocarboxylate anions

Several new anion receptors have been synthesized by introducing one or two urea or thiourea units at the upper rim of calix[4]arenes, blocked in the cone conformation. The difunctionalized receptor 13 shows selectivity n the recognition of acetate anion, which interacts with the two urea units through four hydrogen bonds The monofunctionalized receptors 21 and 22 complex more strongly aromatic carboxylates or butyrate anion since the primary hydrogen bonding contacts are strengthened by weak π/π or CH3/π host-guest interactions.

Aggregates of calix[4]arenes based on the 2,6-diaminotriazine · imide system

The synthesis of several calix[4]arenes functionalized with uracil or diaminotriazine moieties is described. The association between these complementary calix[4]arenes is strongly influenced by processes related to the position and directionality of the hydrogen-bonding moieties. In the case of bis(uracil)calix[4]arene (4), self-association is observed (K = 3.4 · 103 M-1 in CDCl3) whereas, in the case of bis(diamidotriazine)calix[4]arene (16), it was concluded from 1H-NMR studies that intermolecular association is hampered by the formation of intramolecular hydrogen bonds. Due to the divergent orientation of the hydrogen-bonding groups of bis(diaminotriazine)calix[4]arene (15b), it forms hydrogen-bonded strands through interaction with 5-ethyl-5-phenylbarbituric acid (17), resulting in the formation of a gel in chloroform.