Experimental thermochemical study of the monochloronitrobenzene isomers

The standard (p^° = 0.1 MPa) molar enthalpies of formation of 2-, 3-, and 4-chloronitrobenzene isomers, in the crystalline state, at T = 298.15 K, were derived from the standard (p^° = 0.1 MPa) massic energies of combustion, in oxygen, at T = 298.15 K, measured by rotating bomb combustion calorimetry. The standard molar enthalpies of sublimation of the isomers, at T = 298.15 K, were obtained by high temperature Calvet microcalorimetry.     

3.

Experimental thermochemical study of the three methyl substituted 2-acetylthiophene isomers     

Manuel A.V. Ribeiro da Silva  Ana Filipa L.O.M. Santos 《The Journal of chemical thermodynamics》2008,40(8):1309-1313

     

4.

Experimental and computational thermochemical study of the dichloronitrobenzene isomers     

Manuel A.V. Ribeiro da Silva  Ana I.M.C. Lobo Ferreira  Ana Rita G. Moreno 《The Journal of chemical thermodynamics》2009,41(8):904-910

     

5.

Calorimetric and computational thermochemical study of difluorophenol isomers     

Manuel A.V. Ribeiro da Silva  Ana I.M.C. Lobo Ferreira 《The Journal of chemical thermodynamics》2010,42(2):182-188

     

6.

Experimental and computational thermochemical study of the tri-, tetra-, and pentachloronitrobenzene isomers     

Manuel A.V. Ribeiro da Silva  Ana I.M.C. Lobo Ferreira  Joana I.T.A. Cabral  Ana Filipa L.O.M. Santos  Ana Rita G. Moreno  Tiago L.P. Galvão  Inês M. Rocha  Paula M.V. Fernandes  Sílvia Q. Salgueiro  Vanessa A.F. de Moura  Isabel M.S.C. Oliveira  Paula C. Cotelo  Mariana R.A. Ribeiro 《The Journal of chemical thermodynamics》2009,41(9):984-991

     

7.

Experimental thermochemical study of 4,5-dichloro-2-nitroaniline     

Manuel A.V. Ribeiro da Silva  Maria D.M.C. Ribeiro da Silva  Ana I.M.C. Lobo Ferreira  Ana Filipa L.O.M. Santos  Tiago L.P. Galvão 《The Journal of chemical thermodynamics》2009,41(11):1247-1253

     

8.

Experimental and computational thermochemical study of oxindole     

Margarida S. Miranda  M. Agostinha R. Matos  Victor M.F. Morais  Joel F. Liebman 《The Journal of chemical thermodynamics》2010,42(9):1101-1106

     

9.

Experimental thermochemical study of 3-acetyl-2-methyl-5-phenylthiophene     

Manuel A.V. Ribeiro da Silva  Ana Filipa L.O.M. Santos 《The Journal of chemical thermodynamics》2010,42(1):128-133

     

10.

Experimental and computational thermochemical study of 2-thiobarbituric acid: structure-energy relationship     

Roux MV  Notario R  Zaitsau DH  Emel'yanenko VN  Verevkin SP 《The journal of physical chemistry. A》2012,116(18):4639-4645

This paper reports an experimental and computational thermochemical study on 2-thiobarbituric acid (2-thioxodihydropyrimidine-4,6(1H,5H)-dione), [CAS 504-17-6]. The value of the standard (p(0) = 0.1 MPa) molar enthalpy of formation in the gas phase at T = 298.15 K has been determined. The energy of combustion was measured by bomb combustion calorimetry, using a rotatory bomb, and from the result obtained, the standard molar enthalpy of formation in the crystalline state at T = 298.15 K was calculated as -(396.8 ± 0.9) kJ·mol(-1). The enthalpy of sublimation was determined using a transference (transpiration) method in a saturated N(2) stream and a value of the enthalpy of sublimation at T = 298.15 K was derived as (118.3 ± 2.2) kJ·mol(-1). From these results a value of -(278.5 ± 2.4) kJ·mol(-1) for the gas-phase enthalpy of formation at T = 298.15 K was determined. Theoretical calculations at the G3 and G4 levels were performed, and a study of the molecular and electronic structure of the compound has been carried out. Calculated enthalpies of formation are in very good agreement with the experimental value.     

11.

Experimental and computational thermochemical study of 3-hydroxypropanenitrile     

《The Journal of chemical thermodynamics》2007,39(10):1377-1383

     

12.

Unexpected Migratory Insertion Reactions of M(alkyl)2 (M=Zn,Cd) and Diamidocarbenes          下载免费PDF全文

Lee R. Collins  Gabriele Hierlmeier  Dr. Mary F. Mahon  Dr. Ian M. Riddlestone  Prof. Michael K. Whittlesey 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(8):3215-3218

The electrophilic character of free diamidocarbenes (DACs) allows them to activate inert bonds in small molecules, such as NH₃ and P₄. Herein, we report that metal coordinated DACs also exhibit electrophilic reactivity, undergoing attack by Zn and Cd dialkyl precursors to afford the migratory insertion products [(6‐MesDAC‐R)MR] (M=Zn, Cd; R=Et, Me; Mes=mesityl). These species were formed via the spectroscopically characterised intermediates [(6‐MesDAC)MR₂], exhibiting barriers to migratory insertion which increase in the order MR₂ = ZnEt₂ < ZnMe₂ < CdMe₂. Compound [(6‐MesDAC‐Me)CdMe] showed limited stability, undergoing deposition of Cd metal, by an apparent β‐H elimination pathway. These results raise doubts about the suitability of diamidocarbenes as ligands in catalytic reactions involving metal species bearing nucleophilic ligands (M‐R, M‐H).     

13.

Study of thermochemical properties of diphenyl[dialkyl(alkyl)carbamoylmethyl]phosphine oxides     

B. I. Petrov  G. A. Abakumov  A. V. Arapova  E. V. Sharova  O. I. Artiushin  I. L. Odinets  N. M. Lazarev  Yu. A. Bessonova 《Russian Journal of General Chemistry》2011,81(11):2231-2234

The synthesis and the studies of properties of diphenyl[dialkyl(alkyl)carbamoylmethyl]phosphine oxides by differential scanning calorimetry, mass spectrometry and Knudsen effusion method were performed. The thermodynamic parameters of melting and vaporization were calculated.     

14.

Experimental thermochemical study of 5-bromoindole and 5-bromoindoline     

Manuel A.V. Ribeiro da Silva  Joana I.T.A. Cabral 《The Journal of chemical thermodynamics》2009,41(1):84-89

     

15.

Experimental and computational thermochemical study of 2- and 3-thiopheneacetic acid methyl esters     

Roux MV  Temprado M  Notario R  Chickos JS  Santos AF  da Silva MA 《The journal of physical chemistry. A》2007,111(24):5280-5286

Thiophene-based compounds have widespread use in modern drug design, biodiagnostics, electronic and optoelectronic devices, and conductive polymers. The present study reports an experimental and computational thermochemical study on the relative stabilities of 2- and 3-thiopheneacetic acid methyl esters. The enthalpies of combustion and vaporization were measured by a rotating-bomb combustion calorimeter, Calvet microcalorimetry, and correlation gas chromatography, and the gas-phase enthalpies of formation at T=298.15 K were determined. Standard ab initio molecular orbital calculations at the G3 level were performed, and a theoretical study of the molecular and electronic structure of the compounds studied was carried out. Calculated enthalpies of formation, using atomization and isodesmic reactions are in very good agreement with the experimental results.     

16.

Structures of trans-bis(dimethylglyoximato)(alkyl)(1,5,6-trimethylbenzimidazole)cobalt(III) with alkyl = chlorocyanomethyl and adamantyl     

N. Bresciani-Pahor  W. M. Attia  L. Randaccio  C. Lopz  J.-P. Charland 《Acta Crystallographica. Section C, Structural Chemistry》1987,43(8):1484-1487

     

17.

Experimental and computational thermochemical studies of 9-R-xanthene derivatives (ROH,COOH, CONH2)     

《The Journal of chemical thermodynamics》2012

In the present work, the standard (p° = 0.1 MPa) molar enthalpies of formation of xanthydrol, 9-xanthenecarboxylic acid and 9-xanthenecarboxamide, in the gaseous state, at T = 298.15 K, were determined by experimental and computational studies. The experimental techniques used were the static-bomb combustion calorimetry, which enabled the determination of the standard molar enthalpy of formation, in the crystalline state, and the vacuum drop microcalorimetric and the Knudsen effusion techniques used to derive the enthalpy of sublimation. For comparison purposes, we performed standard ab initio molecular orbital calculations, using the G3(MP2)//B3LYP composite procedure, of the enthalpies of several homodesmotic reactions, allowing to extract the standard molar enthalpies of formation, in the gaseous state, of the three xanthene derivatives considered in this work. The calculated results are in good agreement with the experimental data.     

18.

The thermochemical characteristics of AIII(HSiUO6)3 · nH2O series compounds (AIII = Y and Ln and n = 0 and 10)     

N. G. Chernorukov  A. V. Knyazev  T. A. Gur’eva 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2006,80(8):1210-1214

The standard enthalpies of formation of anhydrous rare-earth metal uranosilicates and their decahy-drates were determined by reaction calorimetry at 298.15 K. The standard enthalpies of dehydration and synthesis of these compounds were calculated.     

19.

Structures of two pyridine alkylcobaloximes with alkyl = cyanomethyl and benzyl     

N. Bresciani Pahor  L. Randaccio  E. Zangrando  L. Antolini 《Acta Crystallographica. Section C, Structural Chemistry》1988,44(12):2052-2055

     

20.

Theoretical study of the gas-phase thermolysis reaction of alkyl (ethyl,isopropyl, and tert-butyl) N,N-dimethylcarbamates and N,N-diethylcarbamates     

Camilo?Quijano  Rafael?NotarioEmail author  Jairo?Quijano  Claudia?Sánchez  Luis A.?León  Ederley?Vélez 《Theoretical chemistry accounts》2003,110(6):377-386

Theoretical studies on the thermolysis in the gas phase of alkyl N,N-dialkylcarbamates were carried out using ab initio theoretical methods, at the MP2/6-31G(d), MP2/6-31++G(d,p) and MP2/6-311++G(2d,p)//MP2/6-31G(d) levels. The reactions have two steps: the first one corresponds to the formation of an alkene and a neutral dialkylcarbamic acid intermediate via a six-membered cyclic transition state; the second one is the decarboxylation of this intermediate via a four-membered cyclic transition state, leading to carbon dioxide and the corresponding dialkylamine. The progress of the reactions was followed by means of the Wiberg bond indices. The results indicate that the transition states have character intermediate between reactants and products, and the calculated synchronicities show that the reactions are slightly asynchronous. The bond-breaking processes are more advanced than the bond-forming ones, indicating a bond deficiency in the transition states. The rate constants calculated for all the reactions agree very well with the available experimental data.From the Proceedings of the 28th Congreso de Químicos Teóricos de Expresión Latina (QUITEL 2002)     

Experimental and computational thermochemical study of 2-thiobarbituric acid: structure-energy relationship

This paper reports an experimental and computational thermochemical study on 2-thiobarbituric acid (2-thioxodihydropyrimidine-4,6(1H,5H)-dione), [CAS 504-17-6]. The value of the standard (p(0) = 0.1 MPa) molar enthalpy of formation in the gas phase at T = 298.15 K has been determined. The energy of combustion was measured by bomb combustion calorimetry, using a rotatory bomb, and from the result obtained, the standard molar enthalpy of formation in the crystalline state at T = 298.15 K was calculated as -(396.8 ± 0.9) kJ·mol(-1). The enthalpy of sublimation was determined using a transference (transpiration) method in a saturated N(2) stream and a value of the enthalpy of sublimation at T = 298.15 K was derived as (118.3 ± 2.2) kJ·mol(-1). From these results a value of -(278.5 ± 2.4) kJ·mol(-1) for the gas-phase enthalpy of formation at T = 298.15 K was determined. Theoretical calculations at the G3 and G4 levels were performed, and a study of the molecular and electronic structure of the compound has been carried out. Calculated enthalpies of formation are in very good agreement with the experimental value.     

Unexpected Migratory Insertion Reactions of M(alkyl)2 (M=Zn,Cd) and Diamidocarbenes

The electrophilic character of free diamidocarbenes (DACs) allows them to activate inert bonds in small molecules, such as NH₃ and P₄. Herein, we report that metal coordinated DACs also exhibit electrophilic reactivity, undergoing attack by Zn and Cd dialkyl precursors to afford the migratory insertion products [(6‐MesDAC‐R)MR] (M=Zn, Cd; R=Et, Me; Mes=mesityl). These species were formed via the spectroscopically characterised intermediates [(6‐MesDAC)MR₂], exhibiting barriers to migratory insertion which increase in the order MR₂ = ZnEt₂ < ZnMe₂ < CdMe₂. Compound [(6‐MesDAC‐Me)CdMe] showed limited stability, undergoing deposition of Cd metal, by an apparent β‐H elimination pathway. These results raise doubts about the suitability of diamidocarbenes as ligands in catalytic reactions involving metal species bearing nucleophilic ligands (M‐R, M‐H).     

Study of thermochemical properties of diphenyl[dialkyl(alkyl)carbamoylmethyl]phosphine oxides

The synthesis and the studies of properties of diphenyl[dialkyl(alkyl)carbamoylmethyl]phosphine oxides by differential scanning calorimetry, mass spectrometry and Knudsen effusion method were performed. The thermodynamic parameters of melting and vaporization were calculated.     

Experimental and computational thermochemical study of 2- and 3-thiopheneacetic acid methyl esters

Thiophene-based compounds have widespread use in modern drug design, biodiagnostics, electronic and optoelectronic devices, and conductive polymers. The present study reports an experimental and computational thermochemical study on the relative stabilities of 2- and 3-thiopheneacetic acid methyl esters. The enthalpies of combustion and vaporization were measured by a rotating-bomb combustion calorimeter, Calvet microcalorimetry, and correlation gas chromatography, and the gas-phase enthalpies of formation at T=298.15 K were determined. Standard ab initio molecular orbital calculations at the G3 level were performed, and a theoretical study of the molecular and electronic structure of the compounds studied was carried out. Calculated enthalpies of formation, using atomization and isodesmic reactions are in very good agreement with the experimental results.     

Experimental and computational thermochemical studies of 9-R-xanthene derivatives (ROH,COOH, CONH2)

In the present work, the standard (p° = 0.1 MPa) molar enthalpies of formation of xanthydrol, 9-xanthenecarboxylic acid and 9-xanthenecarboxamide, in the gaseous state, at T = 298.15 K, were determined by experimental and computational studies. The experimental techniques used were the static-bomb combustion calorimetry, which enabled the determination of the standard molar enthalpy of formation, in the crystalline state, and the vacuum drop microcalorimetric and the Knudsen effusion techniques used to derive the enthalpy of sublimation. For comparison purposes, we performed standard ab initio molecular orbital calculations, using the G3(MP2)//B3LYP composite procedure, of the enthalpies of several homodesmotic reactions, allowing to extract the standard molar enthalpies of formation, in the gaseous state, of the three xanthene derivatives considered in this work. The calculated results are in good agreement with the experimental data.     

The thermochemical characteristics of AIII(HSiUO6)3 · nH2O series compounds (AIII = Y and Ln and n = 0 and 10)

The standard enthalpies of formation of anhydrous rare-earth metal uranosilicates and their decahy-drates were determined by reaction calorimetry at 298.15 K. The standard enthalpies of dehydration and synthesis of these compounds were calculated.     

Theoretical study of the gas-phase thermolysis reaction of alkyl (ethyl,isopropyl, and tert-butyl) N,N-dimethylcarbamates and N,N-diethylcarbamates

Theoretical studies on the thermolysis in the gas phase of alkyl N,N-dialkylcarbamates were carried out using ab initio theoretical methods, at the MP2/6-31G(d), MP2/6-31++G(d,p) and MP2/6-311++G(2d,p)//MP2/6-31G(d) levels. The reactions have two steps: the first one corresponds to the formation of an alkene and a neutral dialkylcarbamic acid intermediate via a six-membered cyclic transition state; the second one is the decarboxylation of this intermediate via a four-membered cyclic transition state, leading to carbon dioxide and the corresponding dialkylamine. The progress of the reactions was followed by means of the Wiberg bond indices. The results indicate that the transition states have character intermediate between reactants and products, and the calculated synchronicities show that the reactions are slightly asynchronous. The bond-breaking processes are more advanced than the bond-forming ones, indicating a bond deficiency in the transition states. The rate constants calculated for all the reactions agree very well with the available experimental data.From the Proceedings of the 28th Congreso de Químicos Teóricos de Expresión Latina (QUITEL 2002)