Thermodynamic Study of 1,4-Bis(3-methylimidazolium-1-yl)butane Bis(trifluoromethylsulfonyl)imide ([C(MIm)][NTf]) from 6 to 350 K.

The molar heat capacity of 1,4-bis(3-methylimidazolium-1-yl)butane bis(trifluoromethylsulfonyl)imide dicationic ionic compound ([C(MIm)][NTf]) has been studied over the temperature range from 6 to 350 K by adiabatic calorimetry. In the above temperature interval, this compound has been found to form crystal, liquid, and supercooled liquid. For [C(MIm)][NTf], the temperature of fusion ° = (337.

Thermodynamic Properties of the First-Generation Hybrid Dendrimer with "Carbosilane Core/Phenylene Shell" Structure.

The molar heat capacity of the first-generation hybrid dendrimer with a "carbosilane core/phenylene shell" structure was measured for the first time in the temperature range = 6-600 K using a precise adiabatic vacuum calorimeter and DSC. In the above temperature interval, the glass transition of the studied compound was observed, and its thermodynamic characteristics were determined. The standard thermodynamic functions (the enthalpy, the entropy, and the Gibbs energy) of the hybrid dendrimer were calculated over the range from = 0 to 600 K using the experimentally determined heat capacity.

Thermodynamic Properties of Carbosilane Dendrimers of the Sixth Generation with Ethylene Oxide Terminal Groups.

The temperature dependences of heat capacities of carbosilane dendrimers of the sixth generation with ethyleneoxide terminal groups, denoted as G6[(OCH2CH2)1OCH3]256 and G6[(OCH2CH2)3OCH3]256, were measured in the temperature range from T = (6 to 520) K by precision adiabatic calorimetry and differential scanning calorimetry (DSC). In the above temperature range the physical transformations, such as glass transition and high-temperature relaxation transition, were detected. The standard thermodynamic characteristics of the revealed transformations were determined and analyzed.

Low-temperature polymorphic phase transition in a crystalline tripeptide L-Ala-L-Pro-Gly·H2O revealed by adiabatic calorimetry.

We demonstrate application of precise adiabatic vacuum calorimetry to observation of phase transition in the tripeptide L-alanyl-L-prolyl-glycine monohydrate (APG) from 6 to 320 K and report the standard thermodynamic properties of the tripeptide in the entire range. Thus, the heat capacity of APG was measured by adiabatic vacuum calorimetry in the above temperature range. The tripeptide exhibits a reversible first-order solid-to-solid phase transition characterized by strong thermal hysteresis.

Standard Thermodynamic Functions of Tripeptides -Formyl-l-methionyl-l-leucyl-l-phenylalaninol and -Formyl-l-methionyl-l-leucyl-l-phenylalanine Methyl Ester.

The heat capacities of tripeptides -formyl-l-methionyl-l-leucyl-l-phenylalaninol (-f-MLF-OH) and -formyl-l-methionyl-l-leucyl-l-phenylalanine methyl ester (-f-MLF-OMe) were measured by precision adiabatic vacuum calorimetry over the temperature range from = (6 to 350) K. The tripeptides were stable over this temperature range, and no phase change, transformation, association, or thermal decomposition was observed. The standard thermodynamic functions: molar heat capacity , enthalpy () - (0), entropy (), and Gibbs energy () - (0) of peptides were calculated over the range from = (0 to 350) K.