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hypervalent_iodine

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Everything posted by hypervalent_iodine

  1. Is RP chromatography a possibility? I normally use C18 cartridges on an MPLC unit for any of my peptide work and haven’t had an issue. I would also normally use 20% piperidine in DMF for Fmoc removal, but this is for SPPS so possibly not as easy in solution phase. The other option, which might be a bit much if this is just a single amide bond you’re making or your starting material is precious, is to load it onto a resin and do the synthesis that way.
  2. Thank you, and I’ll say I worked very hard on teaching them how to type / finding an appropriately sized key board, so it’s nice to have my work recognised.
  3. A point I wholeheartedly agree with. There is a lot of literature in the crisis management space that discusses this and treats the increase in frequency and severity due to climate change as a given. The way that plays out in policy is interesting. As a side note, the floods in 2011 didn’t just hit Brisbane either, they impacted roughly 75% of QLD all told. We won’t really be able to know how the damages and costs compare until it’s finished battering the NSW coast, but I would guess you are right that the net effect including NSW (especially Sydney) might tip the net cost over what happened in 2011. It also looks like we’re getting severe thunder storms and giant hail tomorrow up here, so fingers crossed we get through round 2 relatively in tact.
  4. I don’t want to detract from your main point too much, but I have lived in Brisbane through both. The 2011 ones were way worse, but also quite different. Those ones came after months of non-stop rain. They didn’t manage the dams properly and sent a tidal wave down the river when it got to the point where they had no option but to release water. The damage and flood levels were considerably higher in 2011. The house I lived in at the time was thankfully on a hill that became an island for a few days and we were without power for four days, but we were lucky. Even before this weekend there were properties that had not yet recovered from 2011, largely thanks to insurance companies who refused to pay out and people being forced into bankruptcy. These floods came quickly and surpassed predictions, which did mean that people that probably should have evacuated did not. There were a surprising number of deaths, but if I had to guess I’d say the suddenness of it all was at least partly to blame. Properties and areas that didn’t have good drainage suffered badly, but 2011 was still worse.
  5. My assumption is that it is asking you for the masses of each individually to make up a litre of solution with those concentrations and that the first number is meant to be in M. The last bit is an assumption though so I would check that. How much is also kind of vague and not stated but the only way I can think to answer it (it isn’t even really a question it’s just a statement) with that information is with masses.
  6. What reactions have you learnt about so far that might fit? Can you identify where the fragment on the left appears in the product?
  7. While this thread is closed and (I think) being the only person who identifies as female in this thread, I just wanted to provide a little food for thought. Of all the women in my life with whom I am close to, I can't think of a single one who hasn't been sexually assaulted or raped by a man at some point in her life. I cannot say the same about the men I know wrt to false accusations. Anecdotal I know, but something to think about.
  8. I think it’s also important to note that we don’t always agree on a particular course of action such as banning every time it is suggested and will make compromises that everyone can agree to regularly. Conferring with one another isn’t merely an exercise in box ticking.
  9. What, you don’t like rolling 3 month contracts completely contingent on obtaining a portion of the ever-dwindling pools of grant money available? Weird.
  10. After some further discussion, staff have updated the above to now read:
  11. I’ve met a couple of members IRL when I’ve been in the US and have considered them friends at various points. Others I knew digitally when IRC was a thing, and a few I am friends with on FB. These days I generally avoid crossing streams. Difficult to forget that one.
  12. You will need to attempt this yourself before we can help you. What are your thoughts?
  13. Solubility in barium chloride as well.
  14. I agree with Sensei. Get a model kit or even just some tooth picks and blu tack. Make something with four different substituents and make its mirror image, then try and rotate the mirror image so that it is identical to the first molecule. You’ll find that it doesn’t work because they are not superimposable. If you repeat the process but with two substituents that are the same, you should find that you can rotate them to look identical (hence it is not chiral). The example you gave doesn’t work since by your own logic, the two mirror images are superimposable.
  15. You mean by their chemical shifts etc? There are many resources online that will go through it.
  16. It doesn’t. The stereochemistry and how they occupy space is what matters. A good illustration of why this matters in drug design is your feet. They are mirror images of one another but nonsuperimposable in the same way enantiomers are. You will probably know from experience that if you try to put your left shoe on your right foot or vice versa, it won’t fit very well. The same is often true for chiral drug molecules and their molecular targets (eg. enzymes). In the drug world, the quintessential example of why chirality matters a lot is thalidomide, which I’ll let you look up.
  17. I am unsure of what you are wanting to know here, so forgive me if I am off base. The l and d notation refers to the direction a chiral molecule rotates polarised light. To my knowledge, this property doesn't really affect stereochemistry, it's more that it is a consequence of it (i.e. only chiral molecules are able to do it). The reason molecules are able to exist as either l or d is because two enantiomers will rotate polarised light to the same magnitude, but in opposite directions. For example, if one enantiomer of a molecule rotates light by +10o (d), then the other enantiomer will have an optical rotation of -10o (l).
  18. ! Moderator Note I looked at their Google scholar page, and while many of the publications are in Russian, it is pretty clear that this person is not in the business of aerodynamics. Expert? Maybe, but not in the area you are writing in. In any case, as you do not seem to have any new data I see no reason why this should remain open.
  19. Daniel Waxman has been banned as a sock puppet of drumbo.
  20. Sometimes I think about removing it, but I just can't bring myself to pull the trigger.
  21. This is a very good point! I am currently reading a lot in relation to some new (and generally awful) reforms to our higher education sector that were just passed here in Australia. In some of the submissions to parliament, it was highlighted that one the key factors leading to under representation of Indigenous people in universities is that they often don't know what they have available to them. As such, the prospect of enrolling and relocating seems financially daunting and confusing. It is also one of the things that can lead to low levels of retention. Students who live in more metropolitan areas (and more likely to be white) are much more exposed to university life, either through linkages in their school or because someone in their family has been, etc.
  22. ! Moderator Note Unfortunately, we are not in the business with helping with such questions. I also do not believe that squaric acid itself has any medical benefits, so it is not clear what this would achieve.
  23. Yes, sorry, I was writing on my phone so I didn't have time for a full reply. The two exceptions you mention are actually a little misleading. I believe that in reality, they do fill the 4s orbital first, then as electrons start filling up the 3d orbitals one of the 4s electrons moves into the 3d to give 3d54s1 / 3d104s1. It is not a case of only putting one electron into the 4 s and then filling up the 3d orbitals, which is maybe where you are confused with Zn. The reasons for this come down to stability, as you mentioned. It is more favourable to have a completely full or half full set of d orbitals.
  24. Actually, the 4s is filled before the 3d. I suggest looking at the Aufbau principle to help with this, but you can also figure out out by looking at the periodic table if you know where the s, p, d and f blocks are.
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