Experimental and Theoretical Study of the Structures and Enthalpies of Formation of the Synthetic Reagents 1,3-Thiazolidine-2-thione and 1,3-Oxazolidine-2-thione

2009 ◽  
Vol 113 (40) ◽  
pp. 10772-10778 ◽  
Author(s):  
María Victoria Roux ◽  
Manuel Temprado ◽  
Pilar Jiménez ◽  
Concepción Foces-Foces ◽  
Rafael Notario ◽  
...  
Keyword(s):  
Theoretical Study ◽  
Enthalpies Of Formation

Theoretical study on thermochemical parameters and IR spectra of chlorinated isomers of nitrobenzene

2013 ◽  
Vol 91 (10) ◽  
pp. 999-1008 ◽  
Author(s):  
Ibrahem Altarawneh ◽  
Mohammednoor Altarawneh ◽  
Saleh Rawadieh
Keyword(s):  
Experimental Data ◽  
Heat Capacity ◽  
Ir Spectra ◽  
Theoretical Study ◽  
Enthalpies Of Formation ◽  
Geometrical Parameters ◽  
Free Energies ◽  
Calculated Enthalpy ◽  
Standard Enthalpies Of Formation ◽  
Thermochemical Parameters

Thermochemical and geometrical parameters and internal rotation barriers of all chlorinated nitrobenzene isomers were calculated with the G3MP2B3 composite method. Standard entropies, standard Gibbs free energies of formation, standard enthalpies of formation, and heat capacities were calculated and compared with their corresponding available experimental data. Our calculated enthalpy values agree well with the corresponding experimental data. The temperature dependence of entropy and heat capacity has been analysed. All isomers with ortho-chlorine substituents were found to be less stable than other corresponding isomers. Rotational barriers and distortions of the benzene rings were incorporated in the calculations of values for entropy and heat capacity. The IR spectra were calculated and found to be in reasonable agreement with the experimental spectra.

Theoretical study of Si2Hn (n=0–6) and Si2H+n (n=0–7): Appearance potentials, ionization potentials, and enthalpies of formation

1991 ◽  
Vol 95 (4) ◽  
pp. 2433-2444 ◽  
Author(s):  
Larry A. Curtiss ◽  
Krishnan Raghavachari ◽  
Peter W. Deutsch ◽  
John A. Pople
Keyword(s):  
Theoretical Study ◽  
Ionization Potentials ◽  
Enthalpies Of Formation

Theoretical study of annulenes structure [14], [16] and [18] annulenes

1982 ◽  
Vol 47 (6) ◽  
pp. 1705-1720 ◽  
Author(s):  
Dušan Loos ◽  
Jaroslav Leška
Keyword(s):  
Theoretical Study ◽  
Enthalpies Of Formation ◽  
Equilibrium Geometry ◽  
Chemical Methods ◽  
Empirical Potential ◽  
Empirical Potentials ◽  
Quantum Chemical Methods ◽  
Degree Of Aromaticity ◽  
Bond Strengths ◽  
Potential Methods

The quantum-chemical methods EHT, CNDO/2, MINDO/2 and the method of empirical potentials have been used for calculation of equilibrium geometry of six isomers of [14] annulene, four isomers of [16], and three isomers of [18] annulenes. The bond strengths and degree of delocalization are characterized by the overlap populations and the Wiberg indices. Relative stabilities have been determined by comparison of enthalpies of formation calculated by the MINDO/2 and empirical potential methods. Influence of internal strain of the molecules on their stability lowering is discussed. The degree of aromaticity has been determined by calculation of several aromaticity indexes.

Theoretical Study of the Enthalpies of Formation for C40H56Carotenes

2008 ◽  
Vol 112 (1) ◽  
pp. 117-124 ◽  
Author(s):  
Cheng-Yi Tu ◽  
Wen-Hsin Guo ◽  
Ching-Han Hu
Keyword(s):  
Theoretical Study ◽  
Enthalpies Of Formation

DFT and G2MP2 Calculations of the N-N Bond Dissociation Enthalpies and Enthalpies of Formation of Hydrazine, Monomethylhydrazine and Symmetrical and Unsymmetrical Dimethylhydrazine

2004 ◽  
Vol 59 (2) ◽  
pp. 148-152 ◽  
Author(s):  
Manfred A Bohn ◽  
Thomas M Klapötke
Keyword(s):  
Theoretical Study ◽  
Enthalpies Of Formation ◽  
Bond Dissociation ◽  
Unsymmetrical Dimethylhydrazine

In a combined DFT (B3LYP) and G2MP2 theoretical study the following enthalpies of formation (ΔH°f) and bond dissociation enthalpies (BDE) for hydrazine, methylhydrazine (MMH), 1,1- dimethylhydrazine (UDMH) and 1,2-dimethylhydrazine (SDMH) were determined: BDE/kJ mol−1: N2H4, 278±4; MMH, 272±4; UDMH, 259±12; SDMH, 272±12. ΔH°f/kJ mol−1: N2H4, 95±6; MMH, 94±4; UDMH, 80±4; SDMH, 91±4. The bond enthalpy for the N-N bond in hydrazine amounts to BE (N-N, H2N−NH2) = 159±4 kJ mol−1.

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