Long stokes shifts and vibronic couplings in perfluorinated polyanilines

We report the effect of surfactant addition on the optical properties of perfluorinated polyanilines synthesized through liquid–liquid interfaces. We obtained very long Stokes shifts, 205 nm, for oligomers derived from a hydrofluoroether–water system in the presence of Triton X-100 as a surfactant, and vibronic fine features from a toluene-water system

Chemical composition of the brown alga Padina pavonia (L.) Gaill. from the adriatic sea

The chemical composition of the brown alga Padina pavonia (L.) Gaill. from the southern Adriatic Sea was investigated. Twelve sterols were identified in the sterol fraction, the main ones being cholesterol and fucosterol. The main fatty acids in the lipids were also identified.The most abundant fatty acid was palmitic acid, followed by oleic and myristic acids.The concentration of polyunsaturated fatty acids was unusually low for a marine alga. By GC/MS analysis of the volatile and polar fractions, 40 compounds were identified. Some of them probably possess defensive functions. In the volatile fraction free fatty acids, aromatic esters, benzyl alcohol and benzaldehyde predominated. Low concentrations of terpenoids, phenols and sulfur containing compounds were also identified.The nbutanol extract contained mainly fatty acids and polyols. Some of the extracts had an antibacterial activity

Supplementary data for the article: Rašović, A.; Blagojević, V.; Baranac-Stojanović, M.; Kleinpeter, E.; Marković, R.; Minić, D. M. Quantification of the Push-Pull Effect in 2-Alkylidene-4-Oxothiazolidines by Using NMR Spectral Data and Barriers to Rotation around the CC Bond. New Journal of Chemistry 2016, 40 (7), 6364–6373. https://doi.org/10.1039/c6nj00901h

Supplementary material for: [https://doi.org/10.1039/c6nj00901h]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2336

Anion-mediated photophysical behavior in a C60 fullerene [3]rotaxane shuttle

By addressing the challenge of controlling molecular motion, mechanically interlocked molecular machines are primed for a variety of applications in the field of nanotechnology. Specifically, the designed manipulation of communication pathways between electron donor and acceptor moieties that are strategically integrated into dynamic photoactive rotaxanes and catenanes may lead to efficient artificial photosynthetic devices. In this pursuit, a novel [3]rotaxane molecular shuttle consisting of a four-station bis-naphthalene diimide (NDI) and central C60 fullerene bis-triazolium axle component and two mechanically bonded ferrocenyl-functionalized isophthalamide anion binding site-containing macrocycles is constructed using an anion template synthetic methodology. Dynamic coconformational anion recognition-mediated shuttling, which alters the relative positions of the electron donor and acceptor motifs of the [3]rotaxane’s macrocycle and axle components, is demonstrated initially by 1H NMR spectroscopy. Detailed steady-state and time-resolved UV–vis–IR absorption and emission spectroscopies as well as electrochemical studies are employed to further probe the anion-dependent positional macrocycle–axle station state of the molecular shuttle, revealing a striking on/off switchable emission response induced by anion binding. Specifically, the [3]rotaxane chloride coconformation, where the ferrocenyl-functionalized macrocycles reside at the center of the axle component, precludes electron transfer to NDI, resulting in the switching-on of emission from the NDI fluorophore and concomitant formation of a C60 fullerene-based charge-separated state. By stark contrast, in the absence of chloride as the hexafluorophosphate salt, the ferrocenyl-functionalized macrocycles shuttle to the peripheral NDI axle stations, quenching the NDI emission via formation of a NDI-containing charge-separated state. Such anion-mediated control of the photophysical behavior of a rotaxane through molecular motion is unprecedented

Regioselective synthesis of 1,3-thiazines by sequential 4-oxothiazolidine to 1,2-dithiole to 1,3-thiazine transformations: role of intramolecular non-bonded S...O interactions

A new synthetic approach to 2,3-dihydro-4H-1,3-thiazine derivatives based upon reductive rearrangement of 1,2-dithiole-3-ylidene thiones has been developed. In turn, the 1,2-dithiole derivatives were prepared by an efficient ring-opening–closing process of 2-alkylidene-4-oxothiazolidines, induced in the presence of Lawesson's reagent by intramolecular non-bonded 1,5-type S...O interactions in the 4-oxothiazolidine precursors

Quantification of the push-pull effect in 2-alkylidene-4-oxothiazolidines by using NMR spectral data and barriers to rotation around the C=C bond

Information about the strength of donor-acceptor interactions in push-pull alkenes is valuable, as this so-called "push-pull effect'' influences their chemical reactivity and dynamic behaviour. In this paper, we discuss the applicability of NMR spectral data and barriers to rotation around the CQC double bond to quantify the push-pull effect in biologically important 2-alkylidene-4-oxothiazolidines. While olefinic proton chemical shifts and differences in C-13 NMR chemical shifts of the two carbons constituting the CQC double bond fail to give the correct trend in the electron withdrawing ability of the substituents attached to the exocyclic carbon of the double bond, barriers to rotation prove to be a reliable quantity in providing information about the extent of donor-acceptor interactions in the push-pull systems studied. In particular all relevant kinetic data, that is the Arrhenius parameters ( apparent activation energy Ea and frequency factor A) and activation parameters ( Delta S-double dagger, Delta H-double dagger and Delta G(double dagger)), were determined from the data of the experimentally studied configurational isomerization of ( E)-9a. These results were compared to previously published related data for other two compounds, ( Z)-1b and ( 2E, 5Z)-7, showing that experimentally determined Delta G(double dagger) values are a good indicator of the strength of push-pull character. Theoretical calculations of the rotational barriers of eight selected derivatives excellently correlate with the calculated CQC bond lengths and corroborate the applicability of Delta G(double dagger) for estimation of the strength of the push-pull effect in these and related systems.Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3602