Eduardo Alberto Castro

Thermal decomposition of formaldehyde diperoxide (1,2,4,5-tetraoxane) in aqueous solution with an initial concentration of 6.22 × 10⁻³ M was studied in the temperatures range from 403 to 439 K. The reaction was found to follow first-order kinetic law, and formaldehyde was the major decomposition product. The activation parameters of the initial step of the reaction (ΔH ^≠ = 15.25 ± 0.5 kcal mol⁻¹, ΔS ^≠ = −47.78 ± 0.4 cal mol⁻¹K⁻¹, E _a = 16.09 ± 0.5 kcal mol⁻¹) support a mechanism involving homolytic rupture of one peroxide bond in the 1,2,4,5-tetraoxane molecule with participation of the solvent and formation of a diradical intermediate.

A rapidly growing area of modern pharmaceutical research is the prediction of aqueous solubility of drug-sized compounds from their molecular structures. There exist many different reasons for considering this physico-chemical property as a key parameter: the design of novel entities with adequate aqueous solubility brings many advantages to preclinical and clinical research and development, allowing improvement of the Absorption, Distribution, Metabolization, and Elimination/Toxicity profile and “screenability” of drug candidates in High Throughput Screening techniques. This work compiles recent QSPR linear models established by our research group devoted to the quantification of aqueous solubilities and their comparison to previous research on the topic.

A thermochemical rather simple experimental technique is applied to determinethe enthalpy of formation of Diperoxide of ciclohexanone. The study is complemented withsuitable theoretical calculations at the semiempirical and ab initio levels. A particularsatisfactory agreement between both ways is found for the ab initio calculation at the 6-311G basis This set level. Some possible extensions of the present procedure are pointedout.

It is always promising and enticing to start a new editorial task in the scientific arena and the launch of the Chemistry Central Journal is no exception. The different thematic sections making up this journal are quite representative of the whole chemistry enterprise. However, one of them has a special relevance. In fact, Chemical Physics (CP) is the most general and it embodies a wide diversity of issues. Of particular importance at the launch of this groundbreaking new journal is the confidence of the Section Editor in BioMed Central (owners of Chemistry Central) as publishers, and from Chemistry Central to its Editorial Board. I feel deeply grateful for this new assignment and I hope to be able to perform a thorough job in editing this section. Below, I make my request to you as potential authors and reviewers.

The pseudohalide principle has been used extensively in nonmetal chemistry to predict the structure and stability of many molecular species. The 1,2,3,4-thiatriazole-5-thiolate anion, CS₂N₃^-, is of particular interest. In a short communication we have recently reported the topological study of some CS₂N₃^-containing species reported by Crawford et al. Previous reports on these compounds showed that in covalent derivatives not only does the ring remain intact but also the site of attachment of the R group is most likely at the exocyclic sulfur atom in contrast to the previously suggested N−R connectivity. Therefore, the structure and bonding of derivatives of the CS₂N₃^- moiety is clearly an important question. With that in our mind, we undertook a topological analysis, based on the AIM theory, to gain more insight into the bonding in covalent derivatives of the CS₂N₃^- moiety, trying to find an explanation to the origin of the N−H and S−H connectivities. The question is which is the reason that makes all the covalent derivatives prefer the S−R connectivity while the hydracid has an N−H one.

The complexation processes of 1 and 2-adamantanol with l-tryptophan-β-cyclodextrin have been studied using ab initio Hartree–Fock and density functional theory levels. For the host: guest inclusion processes, the up mode with the OH group of the alcohol oriented towards the secondary rim, is found to be in qualitative agreement with the experimental finding. A molecular recognition mechanism is proposed based on the host: guest relative dipole orientation. For the complex with the 2-Ada isomer the host and guest the dipoles are parallels favoring the interaction energy and. This mechanism can explain the small energy difference for the processes involving the adamantanol isomers and modified cyclodextrins.