Interplay of thermochemistry and structural chemistry, the journal (volume 24, 2013, issues 1–2) and the discipline

The contents of issues 1 and 2 for the calendar year 2013 are summarized in the current review of the journal Structural Chemistry. In addition, a brief thermochemical commentary is added to the summary of each paper.     

Interplay of thermochemistry and Structural Chemistry,the journal (volume 29, 2018, issues 3–4) and the discipline

The contents of issues 3 and 4 of Structural Chemistry from the calendar year 2018 are summarized in the present review. A brief thermochemical commentary and recommendations for future research have been added to the summary of each paper.

     

Interplay of thermochemistry and Structural Chemistry, the journal (volume 23, 2012, issues 1–3) and the discipline

In the current review of the journal Structural Chemistry, the contents of the issues 1–3 for the calendar year 2012 are related to thermochemistry. A brief thermochemical commentary is added to the summary of each article.     

Chemisorbed phases of H2O on TiO2 and SrTiO3

Ultraviolet photoemission spectroscopy in ultrahigh vacuum has been used to study the interaction of H₂O with argon-ion-bombarded and annealed TiO₂(110) and SrTiO₃ (100) surfaces. At low exposure, evidence is found for the presence of the OH free radical on both bombarded and annealed TiO₂. At high exposure, a spectrum of slightly perturbed adsorbed H₂O is observed, with the a₁ molecular orbital shifted 0.5–1 eV toward tighter binding. This suggests that H₂O binds to the surface of TiO₂ via its a₁, in-plane O lone-pair orbital. No evidence is found for OH on the surface of SrTiO₃. The spectrum of H₂O adsorbed on bombarded SrTiO₃ shows both the a₁ and b₂ molecular orbitals shifted 0.4 toward tighter binding, indicating a more complicated bonding to the surface. For SrTiO₃ that has been bombarded and then annealed, the spectrum of adsorbed H₂O shows no significant bonding effects.     

Two Polymorphs of 1-(2-Methyl-3-oxoisoindolin-5-yl)urea

Abstract  

4-Ureidophthalimide or ureido isoindolin-1-one based ligands were shown by NMR spectroscopy and theoretical studies to bind the CG base pairs in the major groove. To examine this hydrogen-bonded complex, we cocrystallized 5-fluorocytosine, 9-methylguanine and 1-(2-methyl-3-oxoisoindolin-5-yl)urea. Two polymorphs of the latter compound were obtained during the cocrystallization attempts. Both crystallized in monoclinic space groups: form Ia in P2₁/c with cell parameters of a = 11.382(2), b = 6.042(1), c = 14.102(2) ? and β = 96.51(1)°, and form Ib in P2₁/n with cell parameters of a = 7.092(1), b = 11.643(2), c = 11.580(2) ? and β = 93.48(1)°. An identical molecular conformation of the two polymorphs is observed. Both polymorphs have an R ₂²(8) N–H···O interaction linking the urea fragments of two molecules to a centrosymmetric dimer. Nevertheless, the crystal packing for both forms is completely different. In Ia, two dimers are connected by two R ₂¹(6) N–H···O bonds simultaneously to a shifted ribbon motif, whereas in Ib the two R ₂¹(6) interactions link two molecules from two different dimers.     

Surface analytical investigation of the electrochemical and corrosion behaviour of nanocrystalline FeAl8

From the higher fraction of grain boundaries in nanocrystalline substances a different corrosion behaviour in comparison to the conventional polycrystalline material can be expected, which may be utilised for the development of new corrosion resistant alloys. Therefore, the oxidation behaviour of these two different crystallisation states of FeAl8 was compared by means of electrochemical and surface analytical experiments. The oxide films formed after electrochemical passivation were investigated by Auger Electron Spectroscopy. The application of inelastic peak shape analysis by the method of Tougaard showed, that for both materials the oxide layer may be described by a model of a (below the contamination) buried layer with a thickness of only a few nanometers depending on the preparation conditions. Factor Analysis was applied for the evaluation of the differentiated low energy Auger electron spectra (20–100 eV) as a function of depth profiling sputtering time. For both, the nanocrystalline and the polycrystalline material, the inner part of the oxide layer was enriched in Al, whereas the very outer part (surface region) was enriched in Fe. No differences concerning the sputtering time for removal of the oxide layers were found for the two alloys.