Molecular Modeling Study of the PtCl2 Complexes of Unsaturated S2On+1-Coronands: Dynamic Simulations and Investigation of the Ring Interconversion

Maleonitrile-dithiacrown ethers mn-12S₂O₂ - mn-21S₂O₅ (mn = maleonitrile) are preorganized S₂O_n+1-coronands (n = 1–4) which force B, AB and A class metal ions into mixed S/O coordination spheres. Moreover, they form chelate complexes with MX₂ salts (M = Pd, Pt; X = Cl, Br), which were studied in this paper. The structures of mn-S₂O_n+1 and [PtCl₂(mn-S₂O_n+1)] (n = 2, 3) were investigated theoretically by empirical and semiempirical methods using SYBYL (TRIPOS force field) and MSI/DISCOVER97 (ESFF force field). mn-12S₂O₂ was investigated experimentally by X-ray analysis and 1D and 2D NMR spectroscopy in solution and the complex formation was studied by ¹H, ¹³C and ¹⁹⁵Pt NMR titration experiments, respectively. S-inversion was also investigated in order to determine the ring corresponding interconversional barriers. Different orientations of the macrocyclic ring system mn-18S₂O₄ and of its transition states are shown.Electronic Supplementary Material available.     

Algal eating habits of phycologists attending the ISAP Halifax Conference and members of the general public

A short questionnaire was devised during the 4th ISAP Conference in Halifax (2011) to gather some information on the algal eating habits of the participants. Responses were also collected from random members of the general public in Galway and Copenhagen. Most phycologists had eaten algae before (93%), but few conference participants ate it more regularly than per month. Responses of the general public were similar. A probability model tested the likelihood of a participant eating algae. Neither age nor nationality significantly influenced this probability, although gender increased the probability of eating algae regularly by 9% if the participant was male (at the 90% confidence limit). As hypothesised, being a conference attendee highly significantly increased the probability of eating algae by 22%, in comparison with non-conference attendees (i.e. the general public). The type of phycological research studied also had a significant effect. Researchers working with macroalgae were 22% more likely to eat algae, whereas microalgal researchers were 15% less likely to eat algae on a monthly or more regular basis. The main reasons for eating algae by both groups were ‘taste’, followed by ‘other’ (undefined) reasons, whereas the main reason for not eating algae in both groups was a ‘lack of availability’. Phycologists also ate algae for the perceived ‘health benefits’ (36%), whereas few members of the general public chose this option (13%). Consumption of red seaweeds was most popular (60% of phycologists and 71% of the general public), with Porphyra spp. most commonly preferred. In total, 27 genera of macroalgae and microalgae were recorded as eaten by questionnaire participants.     

Molecular Dynamic and Conformational Study of an Unsaturated 12-crown-S2O2 Ether and its AgI Complexes

The preferred conformations and the complexional behaviour of mn-12S₂O₂ were studied by means of both NMR spectroscopy and molecular modelling. Furthermore, the Ag^I complexes of this ligand mn-12S₂O₂ were also studied by molecular mechanical calculations.