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Additional file 6. Similarity searching and biological activity classification tasks. Plots showing the performance of the QAFFP and Morgan2 fingerprints.

T. V. Beryozkina thanks Russian Foundation for Basic Research, project №18-03-00715.

Фотосинтез и фотобиология

[Figure not available: see fulltext.] It was found that brief refluxing of N-hetarylcyclopentano[d][1,2,3]triazolines in methanol resulted in the elimination of nitrogen, accompanied by cyclopentane ring opening with the formation of N-hetarylvaleramidines. Amidines containing pyrimidine-2,4-dione ring were synthesized by a one-step procedure – the reaction of 5-azidopyrimidine-2,4-diones with endocyclic enamines containing a cyclopentene ring proceeded through an N-pyrimidyl-1,2,3-triazoline intermediate. Triazolines containing a 1,3,5-triazine ring at position 1 did not form valeramidines upon refluxing in methanol. N-(1,3,5-triazin-2-yl)cyclopenta[d][1,2,3]triazoline containing a morpholine ring at position 6a underwent a different type of transformation upon dissolving in acetic acid, resulting in the formation of N-(1,3,5-triazin-2-yl)diaminoalkene. Mechanisms for these transformations are proposed. © 2018, Springer Science+Business Media, LLC, part of Springer Nature. This work was performed with financial support from the Russian Foundation for Basic Research (grant No. 18-03-00715).

© 2016 Informa UK Limited, trading as Taylor & Francis Group.By means of spectrophotometric titration and 1H NMR spectroscopy, the selective binding ability of the Zn-5,15-bis-(2,6-dodecyloxyphenyl)porphyrin towards nitrogen containing organic molecules of various nature has been studied. It has been found that the presence of long alkoxy substituents at the ortho-positions of the Zn-porphyrin phenyl rings prevents the axial coordination of tertiary amines and, conversely, creates favourable conditions for binding of a primary diamine due to the presence of additional binding sites, namely the oxygen atoms of the ortho–ortho′- dodecyloxy substituents of the meso phenyl groups. The formation of stable complexes with multiple binding sites has been confirmed by DFT quantum chemical calculations and two-dimensional NMR experiments.

Fluorescence spectra for a series of mixed phenyl-mesityl 5,10,15,20-tetraarylporphyrins – with Mes4, Mes3Ph, Mes2Ph2- trans, Mes2Ph2- cis, MesPh 3 and Ph4 type architecture (Mes – mesityl, Ph – phenyl) – in their free base, mono- and diprotonated form are reported. Substitution of a single mesophenyl group with a sterically more demanding mesityl group is found to be sufficient to provide stabi-lization of the monoprotonated porphyrin species. A decrease in the number of mesityl substituents in the macrocycle leads to a decrease in the fluore scence quantum yield for protonated forms. The pro-gressive replacement of ortho,ortho’-substituted mesityl groups with unhindered phenyls results in the additive pattern of spectral changes for the free base porphyrins, whereas for both protonated species a specific jump at the trans to cis transition is observed, along with a gradual additive pattern before and afterwards. This feature is interpreted as a signature of the transition between the hindered-like and un-hindered-like conformations of the tetrapyrrolic m acrocycles in the protonated forms. These two mo-lecular conformations provide a different interaction of the two one-electron (a1u,eg) and (a2u,eg) configurations, which leads to changes of their contributions into electronic transitions.

Glassy carbon electrodes were modified by physisorption of two different Co(II)-porphyrins, specifically designed and synthesized to study the effect of the substitution pattern (and the resulting steric hindrance) on the electrocatalytic behavior for a characteristic inner-sphere reaction such as the reduction of oxygen. In spite of the change in morphology caused by a change in the relative positions of the meso substituents, they showed practically the same behavior toward the electro-reduction of O-2. In both cases, water was obtained as the main product. The modified electrodes were also active toward the electro-reduction of hydrogen peroxide. Both electrodes were found stable for more than a month upon exposure to air and the current for the electro-reduction remained practically the same. A.M.V kindly acknowledges CONICYT (Chile) for a doctoral fellowship. M.J.A and J.P. Muena acknowledges Fondecyt (1120071), Mecesup and Dicyt projects. G.R. acknowledges Fondecyt project (1120049). W. Maes, T. H. Ngo and W. Dehaen thank the FWO (Fund for Scientific Research - Flanders), the KU Leuven and the Ministerie voor Wetenschapsbeleid for continuing financial support. T. H. Ngo further acknowledges the IWT (Institute for the Promotion of Innovation through Science and Technology in Flanders) and the Alexander von Humboldt Foundation for a doctoral and postdoctoral fellowship, respectively.

The work presents the synthesis of a novel calix[4]resorcinarene cavitand bearing four 1,3-diketone groups at the upper rim and its complex formation with Tb(iii) ions in DMF and DMSO solutions. Electrospray ionization mass spectra, 1H NMR, UV-Vis and luminescence spectra indicate a long (three hours at least) equilibration time for the complex formation between the cavitand and Tb(iii) in alkaline DMF and DMSO solutions. These results are explained by the restricted keto-enol conversion, resulting from the steric hindrance effect of the methylenedioxy-groups linking the benzene rings within the cavitand framework. A facile synthetic route to convert luminescent Tb(iii) complexes of various stoichiometries into luminescent hydrophilic colloids is disclosed in this work. The route is based on the reprecipitation of the Tb(iii) complexes from DMF to aqueous solutions with further polyelectrolyte deposition without prior separation of the luminescent complexes. The luminescent colloids exhibit high stability over time and in buffer systems, which is a prerequisite for their applicability in analysis and biolabeling. © the Partner Organisations 2014.