Sharif Digital Repository

In this project rotational barrier around the C-N bond in 4-ethyle-morpholine- carboxylate has been studied using DNMR spectroscopy. Spectra were taken at variable temperature, and then with simulation of bandshape broadening pattern at coalescence region, rate constants of exchange were obtained for all temperatures. For simulation of line-shape broadening Spinworks software was used, that with two interfaces made possible simulation with two bandshape simulator programs, DNMR and MEXICO. The rate constants obtained from simulations, were used for calculation of thermodynamic activation parameters (∆G#, ∆H#, ∆S# and Ea). ∆G# 298 value of 13.66 Kcal/mol for 4-ethyle-morpholine- carboxylate... 

The Barrier of the internal rotation around C-N bond in O-ethyle morpholine-4-carbotioate were calculated using dynamic NMR spectroscopy (DNMR) in DMSO solvent. 1H and 13C NMR spectra were recorded at different temperatures (295-350K). Band shape broadening patterns at coalescence regions were simulated to extract rate constants of NMR spectera. Transition state thermodynamic properties of internal rotation around C-N bond in O- ethyle morpholine -4- carbotioate are estimated: , , , . To assay reliability of the estimated values, transition state thermodynamic properties were calculated using PCM model at method and basis set B3LYP/6-311++G(d,p). Theoretical values of thermodynamic... 

In this project rotational barrier around the C-N bond in Ethyl N-(pipyridin carbotioate) has been studied by using DNMR spectroscopy. Spectra were taken at various temperatures , and then with simulation of bandshape broadening pattern at coalescence region, the exchange rate constant of were obtained for all temperatures. For simulation of line-shpe broadening Spinworks software was used, that with two interfaces made possible simulation with two bandshape simulator programs, DNMR and MEXICO. The rate constants obtained from the simulation were used for calculation of thermodynamic activation parameters (... 

In this project rotational barrier of C-N bond in Ethyl N-(pyrrolidine carbotioate) has been studied using DNMR spectroscopy. Spectra were taken at various temperatures, and then with simulation of bandshape broadening pattern, rate constants of exchanges were obtained for all temperatures. For simulation of line-shape broadening SpinWorks software was used,which with two interfaces made possible simulation with two bandshape simulator programs, DNMR and MEXICO. The rate constants obtained from simulations, were used for calculation of thermodynamic activation parameters (?G#, ?H#, ?S# and Ea#).Experimental ?G# 298value(Experimental) of 18.3 Kcal/mol for Ethyl N-(pyrrolidine... 

In this work we have studied conformation of ranitidine by dynamic nuclear magnetic resonance spectroscopy (DNMR) in four different solvents: chloroform, acetone, dimethylsulfoxide, and deuteriumoxide. Ranitidine has three tatumeric forms of enamine, nitoic acid, and imine, but its stable structure is enamine. Temperature dependent 1HNMR spectra of ranitidine which reportet at 500MHz were consistent with the following free activation of energies ΔG# (kcal mol-1): chloroform = 16.2; acetone = 15.4; dimethylsulfoxide = 15.1. The experimental results were confirmed by DFT theoretical calculations at the B3LYP/6-311++G (d, p) level of theory. It was also proved that ranitidine has the form of... 

In this project, rotational barrier of C-N bond in thiobencarb (S-alkyl thiocarbamate) has been studied by HNMR spectroscopy. All the spectra were taken at different temperatures, and then by simulation of bandshape broadening pattern, rate constants for all temperatures were calculated. SpinWorks software was used for the simulation of line shape broadening which has two bandshape simulator programs, DNMR and MEXICO. The obtained rate constants were used to calculate the thermodynamic parameters of activation (ΔG‡, ΔH‡, ΔS‡ and Ea). Experimental ΔG‡298 value for thiobencarb was calculated 15.11kcalmol-1 and 15.86 kCalmol-1 in chloroform and acetone solvents respectively. The computational... 

In this research, the barrier around C-N bond in the molecule of 2-cyano ethyl morpholine-4-carbo dithioate was calculated by dynamic NMR. The 1H-NMR spectra of sample were recorded between temperatures of 240-332 K and 240-328 K in chloroform and acetone solvents, respectively. By analyzing the spectra by SpinWorks software, thermodynamic parameters (ΔG# , ΔH# , ΔS# ) extracded and compared with the data of quantum calculations . In quantum calculations, we compared data in two level (HF and B3LYP ).Consequently, the data of B3LYP method was better .Experimental ΔG# for internal rotation around C-N bond in 2-cyano ethyl morpholine-4-carbo dithioate was 14.04 kcal mol -1 and compared to... 

In this project the energy of rotational barrier of C-N bond in 2-cyanoethyl piperidine-1-carbodithioate has been studied by using Dynamic Nuclear Magnetic Resonance spectroscopy. Spectra were taken at various temperatures in two different solvent; acetone and chloroform. For simulation of line-shape broadening SpinWorks software was used. This with two interfaces made possible simulation with two band-shape simulator programs; DNMR and MEXICO. The rate constants obtained from simulations were used for calculation of thermodynamic activation parameters (ΔG#. ΔH#. ΔS# and Ea#). The computational calculations were done by using Gaussian03 in several level and basis sets that are in good... 

In this project, 13 C nuclear magnetic shielding constants and also hindered internal rotation about C-N bond in compound 4 -(phenylacetyle) morpholine are investigated The Factorial Design method was used to obtain the best solution for chemical shift computations and comparison made out in two levels (HF and B 3 LYP). Consequently the (B 3 LYP) method own better data. 13 C NMR Spectra were taken at variable temperature ,and then with simulation of bandshape broadening pattern at coalescence region ,rate constants of exchange were obtained for all temperatures. For simulation of line-shape broadening Spinworks software was used, that with two interfaces made possible simulation with two... 

NMR spectroscopy as a powerful technique is often used to investigate on structural and conformational studies on proteins and drug compounds. In this work, conformations and structural properties of drug compounds and some nucleoside derivations have been studied using advanced NMR techniques including H-H COSY, HMQC, HMBC and NOESY and quantum based calculations.Experimental analysis on Valsartan show that there are two simultaneous conformers (M and m) with unequal population in M-m type solvents and two stable conformers (N and n) in the N-n type solvents. As the results show, different intramolecular hydrogen bond is the reason for stability af all available conformers. In the... 

In this project rotational barrier of C-N bond in 2-Cyanoethyl-Pyrrolidine-1-Carbodithioate has been studied using DNMR spectroscopy. Spectra were taken at various temperatures, and then with simulation of bandshape broadening pattern, rate constants of exchanges were obtained for all temperatures. For simulation of line-shape broadening SpinWorks software was used,which with two interfaces made possible simulation with two bandshape simulator programs, DNMR and MEXICO. The rate constants obtained from simulations, were used for calculation of thermodynamic activation parameters (ΔG#, ΔH#, ΔS# and Ea#). Experimental ΔG# value of 18.4 Kcal mol-1 for 2-Cyanoethyl-Pyrrolidine-1-Carboditioate in... 

Although CO2 is an environmentally benign solvent, many organic solutes are only sparingly soluble in CO2. We use Monte Carlo simulations in the context of statistical perturbation theory, Widom’s particle insertion and expanded ensemble techniques in order to investigate the molecular properties involved in enhancing the solubility of materials in CO2. Our Monte Carlo simulation of diluted methane and its fluorinated forms showed that substitution of H atom with F atom, results in more favorable solvation, but with further increase of F atom (after CH2F2) due to small size of solute it is impossible for all CO2 molecules in the first solvation shell (FSS) to have a good orientation against... 

In this project, investigation of C-N internal rotation in ethyl tetrahydro-1(2H)-pyridine carbdithioate and ethyl 1-pyrrolidine carbodithioate were investigated by dynamic nuclear magnetic resonance spectroscopy. The 1HNMR and 13CNMR spectra were taken at the variable tempratures around the coalescence temprature. Thermodynamic parameters were calculated by analysing the spectra and the outcomes were compared by the theoretical results. For ethyl tetrahydro-1(2H)-pyridine carbdithioate ∆G‡ was 14.3 (kcal/mol) and for ethyl 1-pyrrolidine carbodithioate ∆G‡ was 17.0 (kcal/mol) which were in accordance with the theoretical results. The analysis were done by the Spinworks program which... 

Carbon dioxide is one of the most significant greenhouse gases in biocycle. This gas makes the equilibrium temperature by absorbing IR radiations on the earth. It is the reason that prevent the earth from freezing. Increasing CO2 emissions in atmosphere, makes problems such as global warming. According to the Kyoto Protocol, all the countries attended to this protocol, must decrease greenhouse gases emissions. Although H2 fuel is one of the best alternative fuel against fossil fuels, the most important industrial process (steam-methane reforming) produce CO2 as by-product. Thus, gas separation has a prominent role in industrial processes such as CO2 capture and H2 purification.Today, gas... 

We used spectroscopic techniques to study self-assembled structures based on nucleobases like G-quadruplexes and macrocycles. Also we used DOSY NMR technique to study hydrogen bonding network in alcohol solutions. First part of our results indicate thermodynamic stability and slow kinetic of G-quadruplexes in apolar aromatic solvents like toluene. Also our results show easy monitoring of formation of each K+ or Na+ complex by NMR, due to the low solubility of alkaline metal salts in apolar media and possibility to stop at any given time in order to control G-quadruplex yield. When combined with suitable functional units, these valuable attributes may be used for the noncovalent synthesis of... 

Metabonomics is a quantitative measurement of time dependent metabolic interactions for living systems in response to the pathological or genetic variations. NMR spectroscopy has emerged as a key tool for understanding metabolic processes in living systems. In this project, the study of metabolomics was performed as classification and regression on samples of parkinson’s disease, multiple sclerosis disease, celiac disease and crohn’s disease. In classification part, various methods were applied using optimal parameters.classification methods in Parkinson’s disease, multiple sclerosis disease, celiac disease and crohn’s disease were RF, CART, PLS-DA, RF and RF respectively. Based on the... 

In this research the relaxation processes of spin nuclei was quantitatively described using computer programs. According to our data, both longitudinal and transverse relaxations consist of five exponentials of the forms of and . The parameters and were represented as a functions of . Analytical expressions were extracted for dynamic frequency shift's components in addition to representing them as a function of . In solving of transverse and longitudinal relaxation's equations, the transverse and longitudinal relaxation matrices were extracted which are useful in the investigation of exchange effect in these nuclei. The accuracy of our computer program was confirmed using it for... 

The study of energy and structure of fentanyl was performed by using quantum mechanical calculations method of Density Functional Theory(DFT) at the computational level B3 L YP and the basis set 6-311++G^(**). Proton-proton and proton-carbon coupling constants were computed around dihedral angles  and . All Karplas equation indicating the relation between coupling constants (namely 〖(_^"1" )"J" 〗_"CH" ^ ، 〖(_^"2" )"J" 〗_"HH" ^ ، 〖(_^"2" )"J" 〗_"CH" ^ ، 〖(_^"2" )"J" 〗_"CH" ^ ، 〖(_^"3" )"J" 〗_"CH" ^ ، 〖(_^"3" )"J" 〗_"HH" ^ and appropriate dihedral angles were extracted. The impact of three water solvents, dimethyl sulfoxide, and carbon tetrachloride with different polarity on the values of... 

The structure and energy of vitamin B1 (Thiamine), vitamin B2 (Riboflavin) and vitamin B6 (Pyridoxine) have been studied employing quantum mechanical calculation, DFT methods at B3LYP level using 6-311+G* basis set. Values of the coupling constants involving carbon-hydrogen and hydrogen-hydrogen on the torsion angle α and β were theoretically calculated. All Karplus equations which represent the correlation between coupling constants 1JCH, 2JHH, 2JCH, 3JHH, 3JCH and proper dihedral angle have been yielded. The effect of three solvents, water, ethanol and carbon¬ tetrachloride with different polarity on coupling constants, energy and structural parameters were calculated employing PCM model.... 

The spin – spin coupling constants have been calculated by the Gaussian 2009 program in order to study the nucleosides conformation. To study the effect of solvent, the calculations were performed in four solvent including water, DMSO, chloroform and Carbon tetrachloride.
Also, the comparison is done on two computing methods including DFT (B3LYP) and HF using 6-311++g** and 6-311g basis set.One bonding (1JC-H), two bonding (2JN-H, 2JC-H) and three bonging coupling constants (3JC-H) have been calculated for unpaired adenosine, thymidine and uridine molecules.Formation of intra-molecular hydrogen bond and electron pair repulsion, respectively, makes the compounds stable and unstable....