Search

Tamarillo is an underutilized fruit in Indonesia, despite the fact that it contains two pigments (anthocyanin and carotenoid) with different properties (polar and non polar). Besides, there is a scarce information about extraction of anthocyanin and carotenoid of Tamarillo using sonication extraction. This study was aimed to investigate the comparison of extraction methods of sonication with maceration on antioxidant potency of anthocyanin and carotenoid of Tamarillo. Two pigmen types (anthocyanin and carotenoid) were extracted using two different methods (sonication and maceration). The parameters of analysis were yield, antioxidant activity (DPPH) with IC50, Ferric Reducing Antioxidant Power (FRAP), anthocyanin total, carotenoid total, phenolic total and scanning electron microscope of cover cell of material. The antioxidant potencies for both anthocyanin and carotenoid by sonication method were higher than those of obtained by maceration method. The results showed that both sonication and maceration were suitable for extraction of anthocyanin and carotenoid from Tamarillo.

Abstrak Studi secara teoritis telah dilakukan untuk mempelajari interaksi senyawa turunan kalkon hidroksi (CH) sebagai sensor kimia dengan anion F-, Cl-, Br-, CN-, CH3COO-, dan NO3-. Penelitian ini bertujuan untuk memodelkan struktur molekul senyawa turunan kalkon hidroksi (CH) dan sifat sensornya serta model interaksinya dengan anion dengan metode DFT. Hasil optimasi geometri menunjukkan terjadinya pemanjangan ikatan O-H sebesar 0,63-0,85 Å dengan adanya anion F-, CN-, and CH3COO-. Hal ini mengindikasikan terjadinya deprotonasi sensor kalkon hidroksi (CH) oleh anion. Sedangkan interaksi sensor kalkon hidroksi (CH) dengan anion Cl-, Br-, dan NO3- hanya berupa ikatan hidrogen dengan pemanjangan ikatan O-H sebesar 0,08-0,46 Å. Sensor kalkon hidroksi (CH) yang mengalami deprotonasi memiliki energi interaksi yang lebih besar yaitu -209,37 – -424,06 kJ/mol dibandingkan sensor yang hanya membentuk ikatan hidrogen yaitu -98,60 – -125,59 kJ/mol. Sensor yang mengalami deprotonasi mengakibatkan turunnya selisih energi HOMO-LUMO dari -3,94 – -4,06 eV menjadi -2,62 – -2,75 eV. Kata kunci: sensor kimia, kalkon hidroksi, anion, DFT Abstract Theoretical study had been carried out to investigate interaction between hydroxy chalcone derivatives (CH) as chemosensors with F-, Cl-, Br-, CN-, CH3COO-, and NO3- anions. This study was aimed to design molecular structures of chemosensor hydroxy chalcone (CH) properties for the anions and their interaction models with DFT method. The result of geometry optimization showed 0,63-0,85 Å O-H bond elongation of the hydroxy chalcone was occured by F-, CN-, and CH3COO-. It was indicated deprotonation of sensor hydroxy chalcone (CH) by anions. Where as the interaction of the hydroxy chalcone (CH) with Cl-, Br-, and NO3- just formed an hydrogen bond with 0,08-0,46 Å O-H bond elongation. Deprotonized sensor hydroxy chalcone (CH) had more energy change of interaction -209,37– -424,06 kJ/mol than sensor which just formed the hydrogen bond -98,60 – -125,59 kJ/mol. Deprotonized sensor caused reduction of the difference of HOMO-LUMO energy from - 3,94 – -4,06 eV to -2,62 – -2,75 eV. Keywords: chemosensor, hydroxy chalcone, anion, DFT

Ab initio of Quantum Mechanics Charge Field Molecular Dynamic (QMCF-MD) of K(I) ion in liquid ammonia has been studied. A Hartree-Fock level of theory was coupled with LANL2DZ ECP basis set for K(I) ion and DZP (Dunning) for ammonia. Two regions as first and second solvation shell were observed. In the first solvation shell at distance 3.7 (Å), K(I) ion was coordinated by four to eight ammonia molecules dominated by K(NH3)6+ species. Second shell of solvation was ranging between 3.7 Å to 7.3 Å. Within simulation time of 20 ps, the frequent exchange processes of ligands indicating for a very labile solvation structure. Four mechanism types of ligand exchange between first and second solvation shell were observed. Mean residence time of ligand is less than 2 ps confirming weak in ion-ligand interaction. Evaluation of K(NH3)6+ using natural bond orbital analysis shows that the Wiberg bond Index is less than 0.05 indicating weak electrostatic interaction of K-N.

Hydrocracking of α-cellulose has been conducted in a semi-batch reactor at 400, 450, and 500 °C with hydrogen flow (30 mL/min.) for 4 h. Mordenite (MOR) and Co, Ni and Pd metal supported on the MOR were used as solid catalysts. The catalysts were characterized using X-ray Diffractometer (XRD), Fourier Transform Infrared (FTIR) spectroscopy, and Scanning Electron Microscopy (SEM) to evaluate the physical-chemical properties. Energy Dispersive X-ray (EDX) and Inductively Coupled Plasma (ICP) were used to analyze the amount of metal impregnated on the catalysts. The liquid product was analyzed using Gas Chromatograph-Mass Spectroscopy (GC-MS). Thermal hydrocracking was also conducted at 450 °C with the amount of liquid product was 37.86 wt.%. The highest liquid conversion obtained by mordenite catalyst was 94.66 wt.% at 450 °C and the highest liquid conversion (98.08 wt.%) was reached by Pd/MOR catalyst at 400 °C.

A quantum mechanical charge field (QMCF) molecular dynamics (MD) simulation has been carried out to describe the structural and dynamical properties of Cu+ ion in liquid ammonia. The first and second shells were treated by ab initio quantum mechanics at the Hartree−Fock (HF) level with the DZP-Dunning basis set for ammonia and LANL2DZ ECP basis set for Cu. The system was equilibrated for 4 ps, then the trajectory data was collected every fifth step for 20 ps at 235.15 K. The structural analysis showed that in the first solvation shell, Cu+ is solvated by 4 ammonia molecules forming a stable structure of tetrahedral with Cu-N bond length of 2.15 Å, whereas in the second solvation shell there are 29 ammonia molecules that have an average distance of 4.79 Å to Cu+ ion. Mean residence time of 3.06 ps was observed for the ammonia ligand in the second solvation shell indicating for a highly unstable structure of the solvation shell. The obtained structure of the first solvation shell from this simulation is in excellent agreement with experimental data.

Determination of effective functional monomer and solvent for R(+)-cathinone imprinted polymer through modeling has been done using density functional theory (DFT) and molecular dynamics (MD) simulation approaches. The selection criteria of the best monomer and solvent are based on the classical potential energy (ΔEMM) from molecular dynamics simulation and confirmed further by quantum potential energy (ΔEDFT) from DFT calculation. The DFT calculation was performed in B3LYP exchange-correlation functional within the 6-31G(d) basis set of function including Polarizable Continuum Model (PCM) solvation effect. From this research, it is obtained that N,N’-methylene bis acrylamide and chloroform are respectively the best candidates for effective functional monomer and solvent, for the synthesis of R(+)-cathinone imprinted polymer.

Objective: To investigate in vitro antimalarial activity of chalcone derivative compounds against Plasmodium falciparum 3D7 (Pf3D7) strain and in silico antimalarial activity. Methods: Synthesis of the chalcone derivatives was conducted via Claisen-Schmidt method using NaOH 60% base as catalyst. An in vitro antimalarial activity assay was carried out according to the Rieckmann method against the chloroquine-sensitive Pf3D7 strain. Molecular docking studies of the prepared compounds were performed using Discovery Studio 3.1 (Accelrys, Inc., San Diego, USA) software to dihydrofolate reductases–thymidylate synthase (PfDHFR-TS) protein with Protein Data Bank ID of 1J3I.pdb (sensitive-protein) and ID: 4DP3.pdb (resistance-protein). Results: This work has successfully synthesized seven chalcone derivatives with a great antimalarial activity. It has been revealed that allyloxy, hydroxy and alkoxy functional groups could increase the antimalarial activity of the chalcone derivatives. The best antimalarial activity of the prepared compounds was possessed by 3b with an IC50 value of 0.59 μM and categorized as an excellent antiplasmodial. Molecular docking studies of 3b showed binding interaction with the amino acid residues such as Ala16, Ile164, Phe58, Tyr170 of the 1J3I.pdb protein and also Ala16, Phe58, Ile112, Met55 of the 4DP3.pdb protein. Conclusions: An in vitro antimalarial assay of the prepared chalcone derivative (3a–g) showed an excellent and good antiplasmodial activity against the chloroquine-sensitive Pf3D7 strain. In silico antimalarial studies revealed that 3a–g made binding interaction with both sensitive-protein (1J3I.pdb) and resistance-protein (4DP3.pdb), which means that they were both active against chloroquine-sensitive and resistant plasmodium strain.

Linear equation of QSAR model of insecticidal activity of carbamate derivatives based on atomic charge and hydrofobic, electronic and steric descriptors has been investigated. The descriptors were calculated by semiempirical PM3 method and biological activities of the compound were taken from experiment. The relationship between descriptors and their biological activities was analyzed with multilinear regression analysis.The best linier equation resulted from that analysis is : Log 1/LD 50 = 12,651 + (2,467 qC2) + (2,832 qC4) - (14,089 qC6) - (0,24 qO7) + (0,293 μ) - (0,08 SA (grid)) +(0,041 V)+ (0,141 EH) - (0,303 log P) n = 39 ; r = 0,839 ; adjusted r2 = 0,612 ; SE = 0,355; Fhit/Ftable = 3,443 PRESS=5,188 Based on that model, a new carbamate derivative has been designed which show better predicted activity (log 1/LD50 = 9,79) while the old one (log 1/LD50 = 8,81). This new carbamate insecticide derivative can be synthesized laboratoriccally for the next prove. Key Word:QSAR, Insecticides carbamate, PM3.

Cocoa bean shell is waste from chocolate industry that containing polyphenol 5.78 % and can be used as natural antioxidant source. The most important step in cocoa processing is roasting. Roasting is needed for developing the chocolate flavor. Chocolate industries do their roasting with low, medium and high degree, depend on product’s necessity. The objective of this research is to determine the effect of roasting degree toward cocoa bean shell antioxidant activity. Cocoa bean roasted at low degree (110 ºC for 60 minutes), medium (140 ºC for 40 minutes) and high (190ºC for 15 minutes). Cocoa bean shell polyphenol was extracted with acetone 70 %. Yield, total phenolic, DPPH free radical scavenging activity as IC50 and inhibition of linoleic acid oxidation was analyzed from crude polyphenol extract. The result shows that the increasing of roasting temperature leads to low yield. Cocoa bean shell polyphenol extract with high roasting degree has the lowest yield (8.07 % b/b). While cocoa bean shell polyphenol extract using medium roasting degree has the highest total phenolic and DPPH free radical scavenging activity of 21.23 ± 0.39 mg GAE/g dry extract and IC50 74.31 ± 0.72 μg/mL, respectively. Cocoa bean shell polyphenol extract is able to inhibit the linoleic acid oxidation. Roasting enhance the inhibition of linoleic acid oxidation compared to extract without roasting about 6%. For the future study, it is needed to identify the cocoa bean shell antioxidant compound during roasting. ABSTRAK Kulit biji kakao merupakan limbah dari industri pengolahan cokelat yang mengandung polifenol sebesar 5,78 %, sehingga berpotensi untuk dimanfaatkan sebagai sumber senyawa antioksidan alami. Tahapan penting dalam pengolahan biji kakao kering adalah penyangraian yang berguna untuk pengembangan citarasa khas cokelat. Industri pengolahan cokelat melakukan penyangraian dengan derajat ringan, sedang dan berat, berdasarkan produk yang dikehendaki. Penelitian ini bertujuan untuk mengetahui pengaruh derajat penyangraian terhadap aktivitas antioksidan kulit biji kakao. Biji kakao kering disangrai pada derajat ringan (110 ºC selama 60 menit), sedang (140 ºC selama 40 menit) dan berat (190 ºC selama 15 menit). Polifenol kulit biji kakao diekstrak menggunakan aseton 70 %. Ekstrak polifenol kering dianalisis rendemen, total fenolik, RSA DPPH yang dinyatakan sebagai IC50 dan penghambatan oksidasi asam linoleat. Hasil penelitian menunjukkan bahwa semakin tinggi suhu penyangraian, rendemen yang diperoleh semakin kecil. Ekstrak polifenol kulit biji kakao dengan penyangraian derajat berat mempunyai rendemen paling kecil (8,07 % b/b). Ekstrak polifenol kulit biji kakao dengan penyangraian derajat sedang mempunyai total fenolik dan aktivitas antioksidan penangkap radikal DPPH paling tinggi yaitu sebesar 21,23 ± 0,39 mg EAG/g ekstrak kering dan nilai IC50 74,31 ± 0,72 μg/mL. Ekstrak polifenol kulit biji kakao mampu menghambat oksidasi asam linoleat. Penyangraian meningkatkan aktivitas penghambatan oksidasi asam linoleat sebesar 6 % bila dibandingkan dengan ekstrak polifenol kulit biji kakao tanpa penyangraian. Perlu dilakukan penelitian selanjutnya untuk identifikasi senyawa antioksidan kulit biji kakao dari hasil penyangraian.

Study on cytotoxicity of diarylaniline derivatives by using quantitative structure-activity relationship (QSAR) has been done. The structures and cytotoxicities of diarylaniline derivatives were obtained from the literature. Calculation of molecular and electronic parameters was conducted using Austin Model 1 (AM1), Parameterized Model 3 (PM3), Hartree-Fock (HF), and density functional theory (DFT) methods. Artificial neural networks (ANN) analysis used to produce the best equation with configuration of input data-hidden node-output data = 5-8-1, value of r2 = 0.913; PRESS = 0.069. The best equation used to design and predict new diarylaniline derivatives. The result shows that compound N1-(4′-Cyanophenyl)-5-(4″-cyanovinyl-2″,6″-dimethyl-phenoxy)-4-dimethylether benzene-1,2-diamine) is the best-proposed compound with cytotoxicity value (CC50) of 93.037 μM.

A QM/MM molecular dynamics (MD) simulation has been carried out using three-body corrected pair potential to investigate the structural and dynamical properties of Zr4+ in dilute aqueous solution. Structural data in the form of radial distribution function, coordination number distribution, and angular distribution function were obtained. The results indicate eight water molecules coordinate to zirconium ion and have two angles of O-Zr4+-O, i.e. 72.0° and 140.0° with a Zr4+-O distance of 2.34 Å. According to these results, the hydration structure of Zr4+ ion in water was more or less well-defined square antiprismatic geometry. The dynamical properties have been characterized by the ligand’s mean residence time (MRT) and Zr4+-O stretching frequencies. The inclusion of the three-body correction was important for the description of the hydrated Zr4+ ion, and the results indicated in good agreement with experimental values.

The roles of counterions, solvent types and extraction temperatures on the selectivity of 18-crown-6 (L) toward alkaline earth salts MX2 (M = Ca, Sr, Ba; X = Cl-, NO3-) have been studied by density functional method at B3LYP level of theory in gas and solvent phase. In gas phase, the chloride anion Cl- is the preference counterion than nitrate anion NO3-. This result is confirmed by the interaction energies, the second order interaction energies, charge transfers, energy difference between HOMO-LUMO and electrostatic potential maps. The presence of solvent reversed the gas phase trend. It is found that NO3- is the preference counterion in solvent phase. The calculated free energies demonstrate that the solvent types strongly change the strength of the complex formation. The free energies are exothermic in polar solvent while for the non polar solvent the free energies are endothermic. As the temperature changes the free energies also vary where the higher the temperatures the lower the free energy values. The calculated free energies are correlated well with the experimental stability constants. This theoretical study would have a strong contribution in planning the experimental conditions in terms of the preference counterions, solvent types and optimum extraction temperatures.

Study on anti-HIV activity of diarylaniline derivative compounds by using quantitative structure-activity relationship (QSAR) has been done. The compounds structure and their anti-HIV activities were obtained from literature. Molecular and electronic parameters were calculated by Austin Model 1 (AM1), Parameterized Model 3 (PM3), Hartree-Fock (HF), and density functional theory (DFT) methods. QSAR analysis was performed using multilinear regression method. The result shows that HF method can produce the best model as follows: log EC50 = 46.418 + (99.360 × qC4) - (67.189 × qC9) - (278.869 × qC15) + (782.466 × qC19) - (127.463 × qO7) n = 20; r2 = 0.815; SEE = 0.393; Fcal/Ftab = 4.185; PRESS = 2.160 Those model can predict a good inhibitory activity (log EC50) value of -0.3359 to compound N1-(4′-Cyanophenyl)-5-(4″-cyanovinyl-2″,6″-dimethyl-phenoxy)-4-hydroxyethylbenzene-1,2-diamine).

The structures, energetic and thermodynamic parameters of crown ethers with different cavity size, electron donating/withdrawing substituent groups and donor atoms have been determined with density functional method at B3LYP level of theory in gas and solvent phase. Small core quasi-relativistic effective core potentials was used together with the accompanying SDD basis set for Sr2+ and DZP basis set was used for crown ether atoms. Natural bond orbital (NBO) analysis was evaluated to characterize the distribution of electrons on the complexes. The interaction energy is well correlated with the values of Strontium charge after complexation, the second order interaction energies (E2) and HOMO-LUMO energy gab (∆Egab). The interaction energy and thermodynamics parameters in gas phase are reduced in solvent phase as the solvent molecules weaken the metal-crown ether interaction. The thermodynamic parameters indicated that less feasibility to extract Sr2+ ion directly from pure water without presence of organic solvent. The theoretical values of extraction energy for Sr(NO3)2 salt from aqueous solution in different organic solvent is validated by the experimental trend. This study would have strong contribution in planning the experiments to the design of specific host ligand and screening of solvent for extraction of metal ion.

The capability of 15-crown-5 ethers to form complexes with some metal cations (Li+, Na+, K+, Zn2+, Cd2+ and Hg2+) was investigated by an ab initio quantum mechanical method. The calculations were performed at the RHF/lanl2mb level of theory. The interaction energies were used to evaluate the metal binding capability of the crown ether. The effect of nature of the metal on the binding properties was also studied. The results of the calculations showed that the interaction energy of the complexes increased in proportion with the ratio of ion charge, electronegativity and ionization potential to the cation diameter. In addition, based on the extraction distribution coefficient in the gas phase, it is found that the 15-crown-5 could not extract metal cations investigated.

Structural properties of Iridium(III) hydration have been studied based on an ab initio Quantum Mechanical Charge Field (QMCF) Molecular Dynamics (MD) Simulations. The most chemical-relevant region was treated by ab initio calculation at Hartree-Fock level. For the remaining region was calculated by Molecular Mechanics method. LANL2DZ ECP and DZP Dunning basis sets were applied to Ir3+ ion and water, respectively. The average distance of Ir-O in the first hydration shell is 2.03 Å. The QMCF MD Simulation can detect only one complex structure with coordination number of 6 in the first hydration shell. Bond angle analysis shows that Ir3+ ion hydration in the first hydration shell has octahedral structure.

Xanthones and their derivatives have been reported to exhibit inhibitory activities towards Plasmodium falciparum. To provide deep insight into the correlation between inhibitory activities and structures of xanthones, linear regression method was employed to establish QSAR models for 16 xanthone derivatives that have diverse structures. The accuracy and predictive power of the proposed QSAR model were verified by semi empirical PM3 method, optimation, and validation. The result showed that the best model is model 3 i.e. Log 1/IC50 = Σ (-1.446)qO(7)+ (-8.775)q.C(12) + (-10.592)qC(13) + 1,979; Y = PRESS = 1.124192.

The dissociative chemisorption of hydrogen on both pure and Sc-incorporated Mg(0001) surfaces have been studied by ab initio density functional theory (DFT) calculation. The calculated dissociation energy of hydrogen molecule on a pure Mg(0001) surface (1.200 eV) is in good agreement with comparable theoretical studies. For the Sc-incorporated Mg(0001) surface, the activated barrier decreases to 0.780 eV due to the strong interaction between the molecular orbital of hydrogen and the d metal state of Sc. This could explain the experimentally observed improvement in absorption kinetics of hydrogen when transition metals have been introduced into the magnesium materials. Keywords: Dissociation, Adsorption, Chemisorptions, DFT, Magnesium

Two steps transformation of (+)-citronellal, cyclization and hydrogenation, on ZnBr2/γ-Al2O3 and Ni/γ-Al2O3 catalyst have been realized with the selectivity to cyclization products (isopulegols) was very high (yield up to ~92.58%) over ZnBr2/γ-Al2O3 under mild condition (90 °C and 1 atm nitrogen atmosphere) with high Brønsted acid concentration, while at the same time very low cyclization rates were achieved over Ni/γ-Al2O3 with low or no Brønsted acidity, respectively. The highest cyclization rates were observed over Ni/ZnBr2/γ-Al2O3 under mild condition (90 °C and 1 atm hydrogen atmosphere). The second step transformation towards cyclization products, hydrogenation to menthols, was performed with Ni/γ-Al2O3 under hydrogen atmosphere. Surprisingly the one-step transformation of (+)-citronellal into menthols was investigated over Ni/γ-Al2O3 with yield ~84% under hydrogen atmosphere (90 °C, 1 atm) by exploiting the presence of acidic and hydrogenation sites on the catalyst surface. On the Ni/γ-Al2O3 catalyst it was found that the cyclization of (+)-citronellal to isopulegols occurs on the surface of the support. In the presence of the noble metal, the isopulegols are further hydrogenated to the menthols. Keywords: cyclization, hydrogenation, citronellal, isopulegol, menthol

Ab initio calculations have been performed in order to investigate the conformational characteristics of p-(nitro)methoxycalix[4]arene and p-(tert-butyl)methoxycalix[4]arene. The structures of four types (cone, partial cone, 1,2-alternate and 1,3-alternate) of conformers for each compound have been optimized by ab initio method at the restricted Møller-Plesset fourth-order perturbation (RMP4) level of theory using 6-311G and 6-311G++(d,p) basis sets. General trends in relative stabilities of p-(nitro)methoxycalix[4]arene and p-(tert-butyl)methoxycalix[4]arene are similar and decrease in following order: partial cone > cone > 1,3-alternate > 1,2-alternate. The calculated results of the most stable conformation of partial cone structure agree with the reported NMR experimental observations. Keywords: ab initio, RMP4, conformational characteristics, p-(nitro)methoxycalix[4]arene, p-(tert-butyl)methoxycalix[4]arene

Relation of electronic structures with their anti malaria activities on artemisinin derivatives was evaluated by means of quantitative structure activity relationship (QSAR) method. To describe electronic structures, atomic charges and dipol moments calculated by quantum mechanics on PM3 semiempirical level. A linear relation between activities and electronic structures was used to construct linear equation models. An equation model showing a good statistically criteria and a realibility of antimalarial activity was chosen to be used to design a compound with new activities against P. facilparum. Results show that 13 equation models were obtained, showing only three models with a good criteria. O2 and C4 atoms were observed for a key role of an improvement of the antimalarial activity. Keywords: artemisinin, antimalaria, atomic charge, dipole moment, PM3

Analysis of quantitative structure - activity relationship (QSAR) for a series of antimalarial compound artemisinin derivatives has been done using principal component regression. The descriptors for QSAR study were representation of electronic structure i.e. atomic net charges of the artemisinin skeleton calculated by AM1 semi-empirical method. The antimalarial activity of the compound was expressed in log 1/IC50 which is an experimental data. The main purpose of the principal component analysis approach is to transform a large data set of atomic net charges to simplify into a data set which known as latent variables. The best QSAR equation to analyze of log 1/IC50 can be obtained from the regression method as a linear function of several latent variables i.e. x1, x2, x3, x4 and x5. The best QSAR model is expressed in the following equation, (;;) Keywords: QSAR, antimalarial, artemisinin, principal component regression

Molecular structures were optimized for the calix[4]arene by ab initio method at the Hartree-Fock level of theory using LANL2DZ and 6-311G basis sets. Conformational equilibrium of four calix[4]arene conformers are reported. The results are compared with experiment, force field, and semiempirical molecular orbital calculations. General trends in relative stabilities of calix[4]arene decrease in following order: cone > partial-cone > 1,2-alternate > 1,3-alternate. The most stable conformer is the cone conformer that is stabilized by an array of four hydrogen bonds and these results agree with the reported experimental observations. All structures were analyzed using theoretical IR, UV-Vis, and 1H NMR spectra attributed to the conformational equilibrium at the Hartree-Fock level of theory using LANL2DZ basis set. Keywords: ab initio calculation, calix[4]arene, conformations, cone

The structure and binding energies of 12-crown-4 and benzo-12-crown-4 complexes with Li+, Na+, K+, Zn2+, Cd2+, and Hg2+were investigated with ab initio calculations using Hartree-Fock approximation and second-order perturbation theory. The basis set used in this study is lanl2mb. The structure optimization of cation-crown ether complexes was evaluated at HF/lanl2mb level of theory and interaction energy of the corresponding complexes was calculated at MP2/lanl2mb level of theory (MP2/lanl2mb//HF/lanl2mb). Interactions of the crown ethers and the cations were discussed in term of the structure parameter of crown ether. The binding energies of the complexes show that all complex formed from transition metal cations is more stable than the complexes formed from alkali metal cations. Keywords: 12-crown-4, benzo-12-crown-4, alkali metals, transition metals

The structure and NMR chemical shifts of endo-cone [CS2(p-methylcalix[4]arene)] complex have been computationally investigated using BIO+ force fields, semi-empirical (PM3) and ab initio (RHF/6-311G++(d,p)) calculations. The first comparison of ab initio NMR chemical shift calculations for a calix[4]arene inclusion complex with solid-state 13C NMR chemical shifts based on the 1:1 complex of p-methylcalix[4]arenes with carbon disulfide in endo-cone complexation mode has been reported. The results showed that ab initio (RHF/6-311G++(d,p)) NMR calculations of the host-guest [CS2(p-methylcalix[4]arene)] complex are in good agreement with experimental solid-state NMR data. Keywords: computational investigation, structure, NMR chemical shifts, [CS2(p-methylcalix[4]arene)].