Thermochemical study of two -benzoyl- , -dialkylureas

A calorimetric study of N, N-diethyl-N′-furoylthiourea and N, N-diisobutyl-N′-furoylthiourea

“…(21,22) As it was previously done for other compounds of the same acylchalcogenoureas family, (7) the self-consistency of the results can be tested from the difference of the enthalpies of formation of the two compounds, which corresponds to the substitution of an ethyl by an iso-butyl group. As estimated previously (7) from group energy contributions, this enthalpic difference should correspond to 99.3 kJ · mol −1 . On the other hand, a simple difference between the corresponding standard molar enthalpies of formation in the gaseous phase (23) yields a difference of (108 ± 3) kJ · mol −1 , well in accordance with the experimental difference found for the pair of thioureas reported in this paper, (110 ± 8) kJ · mol −1 .…”

“…However, there are a few papers about the thermochemistry of related compounds as benzoylureas (7) and on the additivity of thermodynamic properties of alkylureas. (21,22) As it was previously done for other compounds of the same acylchalcogenoureas family, (7) the self-consistency of the results can be tested from the difference of the enthalpies of formation of the two compounds, which corresponds to the substitution of an ethyl by an iso-butyl group. As estimated previously (7) from group energy contributions, this enthalpic difference should correspond to 99.3 kJ · mol −1 .…”

“…Moreover, it is known that the nature of the acyl group and terminal nitrogen atom substituents are important to the coordination ability of the ligands. (4) Therefore, a systematic study of these type of molecules with different substituents has been carried and although a large number of papers (1)(2)(3)(4)(5)(6) have been devoted to the synthesis and physical properties of these kinds of ligands and their complexes, very few studies were published (7) on their thermochemical properties, either in the gaseous or condensed phases.…”

Synthesis, characterization and thermochemical properties of N-acyl-N′,N′-diethylthioureas

“…This is also the situation for the thermochemistry of acyldialkylureas, for which only two compounds have been published. 10 In a previous work, we reported the enthalpies of formation, in the gaseous state, for the compounds PhCONHCON( i Bu) 2 and PhCONHCSN( i Bu) 2 , respectively as Ϫ(445.3 ± 7.5) kJ mol Ϫ1 10 and Ϫ(164.8 ± 4.9) kJ mol Ϫ1 , 35 which enabled us to derive the increment for changing C᎐ ᎐ O to C᎐ ᎐ S, for the pair PhCONHCON( i Bu) 2 -PhCONHCSN( i Bu) 2 , as (280.5 ± 8.9) kJ mol Ϫ1 . This increment is consistent, although larger, with those of identical changes in the pairs acetamide 36 -thioacetamide 37 (251.0 ± 1.4) kJ mol Ϫ1 , benzamide 38 -thiobenzamide 13 (248.7 ± 3.0) kJ mol Ϫ1 and urea 39 -thiourea 40 (258.4 ± 2.0) kJ mol Ϫ1 .…”