Synthesis of Calix[4]pyrroles: A Class of New Molecular Receptor

Calix[4]pyrroles, as a class of new molecular receptor in the area of supramolecular chemistry, have displayed interesting anion and neutral substrate binding properties. In this paper, several new calix[4]pyrrole macrocycles were synthesised and characterized.

Effect of Calix[4]pyrrole as Addition Reagent on Anions Separation in Capillary Zone Electrophoresis (CZE)

Supramolecular interaction of calix[4]pyrroles with several inorganic anions is reported by addition of calix[4]pyrroles to background electrolyte (BGE) in CZE. The retention time (t(R)) of all anions increased with increasing concentration of calix[4]pyrroles. The effect on F- is most evident.

Alkylations of Resorcarenes and Calix[4]pyrroles in Phase Transfer Catalytic Systems

Resorcarens 1a-b (R'=Ph, p-MeOC6H4) were fully alkylated with alkyl iodides or bromides in TEBA/KOH/DMF solid-liquid PTC process with 63-82% yields, whereas the three calix[4]pyrroles 3a-b (2R= 2Me, (CH2)(4), (CH2)(5)) were alkylated with alkyl iodides in TBAB/ 50%NaOH/ CH2Cl2 liquid-liquid PTC system with lower yields (10-38%).

New Subsidiary Interaction Mode of Counteranions with the Periphery Cavity of Calix[4]pyrroles Binding with the Anion Subunits

The solution binding properties of calix[4]pyrroles with anion （as tetraalkylammonium salts） were investigated using UV-Vis spectroscopic techniques. The obvious red-shift of absorption maximum band of calix[4]pyrrole in EtOH in the presence of the tetramethylammonium （TMA^＋） salts or tetraethylammonium （TEA^＋） salts were observed, due to the charge-transfer interactions between the electron-rich pyrrole rings of calix[4]pyrroles and TMA^＋ or TEA^＋ cation subunit. The results indicated that calix[4]pyrrole receptors, which link the anionic species through multiple hydrogen bonding interactions, can use the periphery cavity for selectively binding cation subunits by cation-π charge-transfer interaction. The subsidiary interaction mode helps to further stabilize the calix[4]pyrrole-anion complex.

Synthesis and Properties of Functionalized Schiff Bases of 5α,10α-Di（4-hydroxylphenyl）calix[4]pyrrole and 5α,15β-Di（4-hydroxylphenyl）calix｜4] pyrrole

A series of calix[4]pyrrole meso-substituted Schiff bases was synthesized with 5α,10α-di（4- hydroxylphenyl）calix[4]pyrrole or 5α,15β-di（4-hydroxylphenyl）calix[4]pyrrole as starting materials. The synthetic routes included alkylation with methyl a-chlroroaceate, ammonolysis with alkylene diamine, and condensation with salieylladehyde or 2-hydroxynaphthaldehyde. The crystal structures of the new calix[4]pyrroles and their Schiff bases were determined by X-ray diffraction. The coordination properties of the representative ealix[4]pyrrole Sehiff bases to transition metal ions were also investigated by UV-Vis spectra.

Research on Inorganic Anion Recognition of Calix[4]pyrroles and Dipyrrylmethanes by Capillary Zone Electrophoresis

Capillary electrophoresis （CE） can separate charged and neutral substances with high speed and efficiency. In this paper, utilizing meso-octamethylcalix[4]pyrrole, meso-tetraspirocyclohexylcalJx[4]pyrrole, bimethyl bi（2-pyrryl）- methane and 1,1-bi（2-pyrryl）cyclohexane as additives in capillary zone electrophoresis （CZE） electrolyte, their recognition ability to inorganic anions was discussed. The dipyrrylmethanes have better recognition ability than others. Their effects on separation of seven normal inorganic anions by CZE were studied.

Turn-on fluorescence probe for selective detection of Hg(Ⅱ)by calixpyrrole hydrazide reduced silver nanoparticle: Application to real water sample

A simple and quick method for the synthesis of water dispersible stable silver nanoparticles has been developed. Calix[4]pyrrole octahydrazide （CPOH）, has been successfully used as a reducing as well as stabilizing agent for the synthesis of silver nanoparticles. CPOH-AgNps have been duly characterized by SPR, PSA, TEM and EDX-ray. The ability of CPOH-AgNps as selective and sensitive sensor for various ions （Pb（Ⅱ）, Cd（II）, Mn（Ⅱ）, Fe（Ⅲ）, Ni（Ⅱ）, Zn（Ⅱ）, Hg（Ⅱ）, Co（Ⅱ）, Cu（Ⅱ）） by colorimetry and spectrofluorimetry has been explored. CPOH-AgNps were found to be selective only for Hg（Ⅱ） ions. Nanomolar concentration of Hg（Ⅱ） ions can also be determined by spectrofluorimetry by increase in fluorescence intensity. Linear range of detection of Hg（Ⅱ） ions in water was found to be from 1nmol/L to mol/L. The method has been successfully applied for determination of Hg（Ⅱ） ions in ground water and industrial effluent waste water samples.

Synthesis and crystal structure of Ni,Cu complexes of 5-methyl-10,10,15,15,20,20-hexaethylcalix[4]pyrrole mono-Schiff bases

The functionalized calix[4]pyrrole meso-substituted Schiff bases were conveniently prepared by four- step synthetic route. Furthermore, the nickel and copper complexes of calix[4]pyrrole meso-substituted Schiff base with 1：2 stoichiometry were obtained. The crystal structures of the calix[4]pyrroles and their metal complexes were determined by X-ray diffraction.