Langmuir-Schaefer Film Investigation and Density Functional Theory Band Gap Calculations of Calix[n]arene-Para-Aminobenzoic Acid for Drug Nanosensor Application

Calix[n]arenes was utilized to detect PABA,the primary sunscreen component.This study investigates the interaction of calix[4]arene(C4),calix[6]arene(C6),and PABA using the Langmuir method and first-principle density functional theory(DFT).Using the Langmuir-Schaefer(LS)technique,an ultrathin film composed of calix[n]arenes and their complexes with PABA was deposited on various substrates.Based on the Langmuir study,the PABA molecule was bonded to the lower rims of both C4 and C6 with the host-guest ratio of 1:1.All of the LS films formed were then characterized by ultravioletvisible spectroscopy(UV-Vis),Fourier-transform infrared spectroscopy(FTIR)and carbon,hydrogen,nitrogen,sulfur elemental analyzer(CHNS).The band gap reduction obtained in the DFT study denotes the charge transfer interaction with promising reactivity between the calix[n]arenes and PABA.The sensing of PABA by C4 and C6 is successful based on the formation of bonding between them due to the hosts’effective trapping capacity.The outcomes of this study could be applied to drug delivery systems for future pharmaceutical and medical applications.

Synthesis and Crystal Structure of Calix[4]arene Bearing a 1,8-Bis(propoxy)anthracene-9,10-dione

The title complex （C50H44C14O8） was synthesized and structurally determined by single-crystal X-ray diffraction method. It crystallizes in monoclinic, space group P21/n with a = 19.7768（4）, b =10.2085（2）, c = 21.2721（4）A,β= 97.153（1）°, V = 4261.23（14）A^3, Z = 4, Mr = 914.65, F（000） = 1904, Dc = 1.426 g/cm^3,μ = 0.336, the final R = 0.0550 and wR = 0.1647. The compound was structurally characterized by IR and ^1H NMR. The molecules are stacked through C-H...π interactions and intermolecular C-H...O hydrogen bonds.

Separation of Salbutamol by Nano-baskets of Calix[4]arene Bearing Sulfonyl-carboxamides in Partial-cone Conformation

Salbutamol,which increases the muscle mass and decreases the adipose tissue,is misused as nutrient repartitioning agent in the livestock.The novelty of this work is the determination of salbutamol in the livestock meat via new bonded-phases bearing eight derivatives of p-tert-calix[4]arene in partial-cone conformation.The new synthesized bonded-phases were characterized and optimized.The bonding interactions of solute and stationary-phases were examined and the main interactions were reported.The salbutamol levels in six samples of livestock meat were analyzed and the results reveal that for the best bonded-phases,the limit of detection（LOD） and limit of quantitation（LOQ） were 0.02 and 0.06 μg/mL,respectively.

Synthesis of Bis-substituted Calix[4]arenes and Mechanism of Substituents Effect on K^+ and Hg^(2+) Ions Transports through Liquid Membrane

New calix[4]arene derivatives containing nitro,amino and benzoyl in the upper and lower rims of molecule were successfully synthesized.Their effectiveness towards K+ and Hg2+ across bubbling liquid membrane(BLM) was examined.For K+ ion transfer,preserving phenolic hydroxyl in the lower rim of calix[4]arene could enhance its transport ability.When benzoyl replaced phenolic hydroxyl,the transport would fall off,because benzoyl caused steric hindrance on the K+ transfer.The study also revealed that the group having the electron-withdrawing conjugative effect on phenolic hydroxyl,-NO2 in the upper rim of calix[4]arene,made transport ability of calix[4]arene fall off.On the contrary,-NH2 that had electron-repulsive conjugative effect enhanced the transport ability of the compound.For Hg2+ ion,only -NH2 in the upper rim of calix[4]arenes had high affinity for it and contributed to Hg2+ transfer.Transport amount of Hg2+ ion increased with increasing calix[4]arene5 concentration and ΔpH in BLM.

A New Efficient Synthesis of p-Nitrocalix[4]arene

A new efficient synthesis of p-nitrocalix[4]arene from calix[4]arene by using nitrogen dioxide is described. The compound is an useful intermediates for the introduction of other functional groups to obtain N containing substituted calix[4]arene. The reaction mechanism is briefly discussed.

Calix[4]arene Polyaza Derivatives: Novel Effective Neutral Receptors for Cations and α-Amino Acids

Introduction Calixarenes are one of the most important supra- molecular building blocks, which can be modified by introducing different functional and/or structural groups to create a specific interaction between the host and the target molecules, such as metal cations and small organic molecules. In particular, the recognition of amino acids is an interesting theme in biomimetic chemistry.

Synthesis of Calix[4] arene Thia Derivative and Extraction Effect of Substituents on Mercury( Ⅱ) and Lead( Ⅱ)

Calix[4]arene derivatives have been reported to possess high selectivity for metal ions.In order to analyze the extraction effect of substituents on Hg^(2+)and Pb^(2+),calix[4]arene derivatives containing hydroxyl,bromoethoxy and 1,11-dioxa-4,8-dithiahendecene were successfully synthesized,with their extraction effectiveness towards Hg^(2+)and Pb^(2+)were evaluated respectively.The results indicated that the phenolic hydroxyl in calix[4]arene improved the extraction ability on Hg^(2+)by promoting the formation of the negative oxygen ions that could bind with Hg^(2+)by coordination and ionic bonds.The extraction ability of 5,17-dinitro-26,28-(1’,11’-dioxa-4’,8’-dithiahendecene)-calix[4]arene(calix[4]arene thia derivative)was improved slightly due to the better coordination capacity for metal ions after introduction of 1,11-dioxa-4,8-dithiahendecene,which was a chelate-binding centre.Regarding to Pb^(2+),only 1,11-dioxa-4,8-dithiahendecene on molecule contributed to extraction due to the coordination bond.Since the metal ion with higher charge-to-radius ratio could coordinate with one ligand more stably,Pb^(2+)with higher charge-to-radius ratio than Hg^(2+)was coordinated and extracted by the calix[4]arene thia derivative more easily.Furthermore,extraction rates of the calix[4]arene thia derivative on both ions(Hg^(2+)and Pb^(2+))increased with the increase of pH value in acidic aqueous system(pH<7).

Synthesis of Schiff Base Calix[4]arene Crowns

This letter reports the synthesis of Schiff base calix[4]arene crowns containing m-xylylene phenol subunit, in which calix[4]arene Schiff base crowns 2a, 2b and 2c were formed by 1:1 condensation of calix[4]arene diamine 1 with dialdehydes (2, 6-diformyl-4-chlorophenol 3a, 2, 6-diformyl-4-methylphenol 3b, 2, 6-diformyl-4-tert-butylphenol 3c) under high dilute condition in refluxing anhydrous ethanol in 65-70% yield.

Syntheses and Binding Properties of Novel Calix[4]arene Derivatives Containing Multiple Azo-groups

Calixarenes are excellent scaffolds that can De modified by introducing various functional groups to create specific interactions between the host and guest molecules. Thus, many calixarene derivatives containing special functional groups, such as ester, amide and thiourea, have been synthesized and their excellent complexing capability for cations have also been studled. Lately, calixarene derivatives containing two or more sorts of functional groups have attracted much attention.

Synthesis of a novel calix[4]arene-based fluorescent ionophore and its metal ions recognition properties

A novel fluorescent ionophore derived from calix[4]arene and pyrazoline was designed and synthesized.Its molecular structure was confirmed by ^1H NMR and element analysis.The resulting material shows specific fluorescent behavior toward the Zn^2＋ion among the other divalent metal ions,such as Co^2＋,Ni^2＋,Cu^2＋.The primary results indicate this ionophore material is a potential material for developing efficient fluorescent Zn^2＋ chemosensors.

A fluorescent probe for fluoride ion based on 2-aminopyridyl-bridged calix[6]arene

An 2-anfinopyddyl-bddged calix[6]arene on the upper rim fixed in cone conformation （3） was successfully synthesized and its highly selective recognition towards fluoride ion was proved by fluorescent and 1H NMR titration experiments.

On-line Preconcentration and Determination of Trace Metals in Water Samples by Flow Injection Combined with Flame Atomic Absorption Spectrometry via Calix[4]arene Carboxylic Acid Packed Micro-column

An adsorbent calix[4]arene carboxylic acid was employed as the adsorption material for on-line flow in jection（FI） micro-column preconcentration coupled with flame atomic absorption spectrometry（FAAS） determination of trace heavy metals（Cu, Pb, Co, Ni and Cd）. Parameters such as the pH, loading time and flow rate of sample, and the concentration, volume and flow rate of eluent were optimized. The enrichment factors are 50.0, 56.5, 11.6, 12.1 and 19.1 for Cu, Pb, Co, Ni, and Cd, respectively, and a sample throughput of 20 h–1 was obtained. The limits of de tection for Cu, Pb, Co, Ni, and Cd were in a range of 1.56―3.91 μg/L, and the relative standard deviations（RSDs） were less than 2.76%（n=7）. Furthermore, the proposed method was successfully applied to the determination of Cu, Pb, Co, Ni, and Cd in certified reference materials and various water samples.

Synthesis, Crystal Structure and Anti-integrase Activity of 25,27-Bis[(Z)-4-(p-methoxyphenyl)-4-hydroxybut-3-en-2-one-1-methyl]-26,28-dihydroxycalix[4]arene

The title compound （C50H.44010） was synthesized and structurally determined by single-crystal X-ray diffraction method. It crystallizes in monoclinic, space group P21/c with a = 16.713（4）, b --- 13.189（3）, c = 19.434（5） A, β = 104.411（4）°, Mr = 804.85, Dc = 1.288 g/cm3, V = 4149.2（17） A3, Z = 4, F（000） = 1696, #（MoKa） = 0.089 mm-1T = 296（2） K, 7279 independent reflections with 3172 observed ones （I 〉 2δ（/））, R = 0.0520 and wR = 0.1203 with GOF = 0.928 （R = 0.1464 and wR = 0.1657 for all data）. The calixarene moiety maintains the symmetric cone conformation through intramolecular O-H…O hydrogen bonds. Preliminary bioassays indicated that the title compound has a potent inhibitory activity against the strand transfer process of HIV-1 integrase.

One-dimensional Inclusion Polymers of Calix[4]arene Monomethoxycarboxylic Acid

X-ray crystal structures of the inclusion complexes of calix[4]arene monomethoxycarboxylic acid 1 （C30H2606） with acetontrile and acetone are reported. The crystal of C30H26O6·CH3CN is of monoclinic, space group P2 1/c with a = 11.691（5）, b = 13.753（5）, c = 17.072（7）A, β = 100.104（7）°, C32H29NO6, Mr = 523.56, V = 2702.4（18）A^3, Z = 4, De= 1.287 g/cm^3, μ（MoKα） = 0.089 mm^-1, T = 293（2） K, 5570 independent reflections with 3220 observed ones （1 〉 2σ（I））, R = 0.0521 and wR = 0.1132 with GOF = 1.042 （R = 0.1055 and wR = 0.1350 for all data）. The data for C30H26O6·CH3COCH3： monoclinic, space group P2 1/c, α = 12.366（4）, b = 12.119（4）, c = 18.796（6） A, β = 90.871（6）°, C33H32O7, Mr = 540.59, V = 2816.6（16）A^3, Z = 4, Dc = 1.275 g/cm^3, μ（MoKα） = 0.089 mm^-1, T = 293（2） K, 5783 independent reflections including 2580 observed ones （I 〉 2σ（I））, R = 0.0555 and wR = 0.1424 with GOF= 0.975 （R = 0.1601 and wR = 0.1884 for all data）. Their architectures exhibit one-dimensional inclusion polymers which are mediated head-to-tail by the guests.

Synthesis and Characterization of Picolinamide Calix[6]arenes Derivatives

Three full-substituted calix[6]arenes containing the picolinamide groups were synmesized and characterized by IR, ^1HNMR and MS, after series reactions, including lower rim etherification, upper rim ipso-nitration, reduction, amidation.

Synthesis and Characterization of Boron Complex of Calix[4]arene

A new boron complex of calix[4]arene was synthesized by the reaction of calix[4]arene with BMS; and the structure of the product was characterized by IR- (HNMR)-H-1. (CNMR)-C-13, (BNMR)-B-11 and MS spectra.

Synthesis of Pyridylazo-substituted Chromogenic Calix[4]arenes

This letter reports a novel method for preparing chromogenic calix[4]arenes, in which the 4-aminopyridine was diazotized with isoamyl nitrite in EtONa/EtOH, and mono(azo)-, bis(azo)- and tetra(azo)-substituted calix[4]arenes were obtained as main product respectively by diazo-coupling in different molar ratio to calix[4]arene in non-aqueous solution at 0-5 degrees.

Nano CaCO_3 : An Unique Condensation Agent for the Preparation of Monosubstituted Calix[4]arene by Ring-opening Reaction

Nano CaCO3 was used as a condensation agent in the ring-opening reaction of p-tert-butylcalix[4]arene with epichlorohydrin to afford 5,11,17,23-tetra-tert-butyl-26,27,28-trihyd- roxy-25-(1-chloro-2-hydroxy-3-propyl)calix[4]arene regioselectively in 52% yield. The yield was less than 2% by using normal CaCO3 instead of nano one under the same conditions.

Synthesis of Calix[4]arenes with Dendritic Fragments

The 1,3-distally selective functionalization of calix[4]arenes with benzylicbromides at the lower rim in excellent ytelds is described. The calix[4]arenes withdendritic fragnents obtalned exist in cone conformation.

Determination of Vanadyl Porphyrins by Liquid-liquid Microextraction and Nano-baskets of p-tert-Calix[4]arene Bearing Di-[N-(X)sulfonye Carboxamide] and Di-(1-propoxy) in Ortho-cone Conformation

Dispersive liquid-liquid microextraction technique was introducd to remove the centrifuging step and conduct inclusion microextraction of charged porphyrins by nano-baskets. For nano-baskets of p-tert-calix[4]arene bearing di-[N-（X）sulfonyl carboxamide] and di-（1-propoxy） in ortho-cone conformation was synthesized and used. The related parameters including ligand concentration, the volume of water disperser, salt effect, and extraction time were optimized. The linear range, detection limit（S/N=3） and precision（RSD, n=6） were determined to be 0.2―50, 0.07 μg/L and 5.3%, respectively. The results reveal that the new approach is competitive analytical tool and an alternative of the traditional methods in the crude oil and related systems.