hypervalent_iodine

The SO2 will smell somewhat like fireworks or a just-struck match. SO3 is stronger in its smell than SO2 and is often described as having a suffocating smell. You really would not want to smell them though, considering the risks. SO2 is toxic via ingestion and SO3 will react with water in the air and in your body to make sulphuric acid, which is quite harmful if you swallow it or inhale it. As for the colour. The FeSO4.7H2O will have a bright blue-green colour. The Fe2O3, which is Iron (III) oxide (aka rust) will be a red-brown colour.

Do you have access to a research laboratory? If not, this is all going to be very hard for you to do in a practical sense. Ignoring that and ignoring the biological aspects, identifying the compounds it secrets will be extremely difficult if not impossible for you to do without a strong background in structure elucidation and organic chemistry as well as access to an NMR and mass spec machine (at the very least). Determining the absolute structure of a compound is often made to look easier than it actually is. It requires a great deal of precise training and prerequisite knowledge to understand the techniques and interpret the data outputs correctly. When you have no clue as to the compound you are looking at, the task is harder again. If you are looking for a specific compound with suspected bioactive profiles and your aim is to isolate, characterise and market it, make sure the next 10 or 20 years are free for you to do work. Truth be told, without the resources, funding and access, achieving this is impractical and most likely not work. If you are not doing this simply for your own benefit, your task will be much simpler though will still prove somewhat unfeasible should you not have the necessary equipment or chemical/biological knowledge at your disposal.

Hmm. I might have a look-see throughweb of science when I get home. Potentially, the compound may not have been isolated and characterised.

Honestly. I go away to do science for a week, and people start topics that I can answer, but that have already been answered. (I'm looking at you, Horza). I literally just presented a lecture on this subject 2 days ago. Dan, you mentioned chiral solvents. They are expensive and useless and deuterated NMR solvents would be even more expensive. As Horza said, the use of chiral NMR solvents isn't particularly useful for the large and complex molecules we like to try and make. In terms of their use as an asymmetric synthetic promoter, they are probably one of the most daft agents out there. It costs more money to obtain something that is enantiomerically pure than not, as I mentioned. Solvents being used in large quantities compared to the rest of the components of your reaction makes the whole concept ridiculously unfeasible. In my research for the lecture I presented on Wednesday, I was in fact only able to come up with one paper that used a chiral solvent in their reaction. The thing I found really laughable was that it didn't even work on its own. To give an ee of above 80%, the reaction needed a catalytic amount of enantiomerically pure proline. There is another reason why we use racemates. Horza eluded to the fact that we often do not know which stereoisomer we want. Depending on what your product is designed to do, this may mean that we don't know which stereoisomer confers bioactivity or 'gives the best result' (most natural products we synthesis are studied because of their medicinal properties - it's how we gratuitous chemists get money to do science). Even if we did have an inclination as to which stereoisomer we wanted, we have to be able to present a full activity profile of the compound we are making - and that includes all possible stereoisomers. If we can't do that, it doesn't bode particularly well for in the case where we want to push it through the rigour of the drug design and development process. If you wanted to synthesise a single enantiomer of something, then there are many ways you might choose so as to achieve this. For most practical purposes, asymmetric synthesis will necessitate the use of some enantiomerically pure, chiral component. These may be: - chiral solvents As I said, these are mostly useless due the cost and need for a high excess of solvent - having said that, chiral solvating agents are a reasonably good alternative, though not often used. - chiral reagents Many of these fall into the latter category of catalysts. The only true reagent under this category is a LiAlH4 ester of darvon alcohol to mediate a enantioselevtive reduction. Nice concept, but it doesn't really work terribly well. - chiral adjuvants/auxiliaries Historically useful, though mostly superseded by recent developments in chiral catalysts - however they remain the only viable route for a number of synthetic transformations. It's based on a similar concept to kinetic resolution - add a temporary chiral moiety to a prochiral compound. The diastereomeric relationship invoked by this conjugation leads to transition states/intermediates/end products of differing energies and will thus favour the formation of one isomer over the other. It of course relies on the group being orthogonal and easily put on/taken off and that upon its removal, stereogenicity is retained. Recyclability is also nice. - chiral catalysts These are the method of choice, where possible. They are cheap by virtue of the fact that they are used in small amounts and are regenerated. An example of this is in Sharpless' epoxidation and dihydroxylation reactions. The assignment of absolute stereochemistry is achieved only through X-ray crystallography (NMR, etc. cannot do this). The problem of this is that it needs, well, crystals. This isn't always possible. Before the development of X-ray crystallography, the determination of stereochemistry was all relative. You should look at the work of Fischer for a better idea of this. What he did was a combination of sheer brilliance and pot-luck. He was able to assign the relative configurations of 3, 4, 5 and 6 membered sugars starting from glycerol through a series of chemical transformations and observations. By a process of sheer luck, he also assigned their absolute configurations, as was found some time after in one of the first published demonstrations of the use of X-rays in this manner. A lot of the time, indeed most of the time, we tend to operate with relative designations. This is okay, provided we use reactions with predictable and well-tested models. Often, the correlations made on asymmetric protocol are speculative and empirical (you should take a look at Horeau's method for determining stereochemistry of secondary alcohols - you can't get much more empirical), with no definitive mechanism. The problem then comes with the ever-present 'exception to the rule', though you can usually discern this via NMR, given that you know the absolute configuration of the rest of your product. To your last post: Certainly, this would be your first port of call. TLC is by no means a fantastic analytical tool (good, but not fantastic). It's helpful if you want a rough guesstimate as to the progress of your reaction or the location of various compounds following column chromatography. Where it falls down though is in the case that a compound you want and some by-product has a similar RF. In combination with what mississippi was saying, this can be a real nightmare. NMR will generally tell you that something is up, particularly if the concentration of one is greater than another (your integrations will look crazy). Anyway, I feel that I am rambling and should probably stop.

Always good to see my screen-namesake put to good use. Although it should be said that I in fact use a different hyperiodine complex for a different reaction. Still, I love all hyperiodine complexes equally. They are amazing. A good alternative to IBX that is markedly more soluble is safe IBX, or SIBX. Alternatively, DMSO is a good solvent, as can be oxane in water. DMP, a derivative of IBX, is also a fantastic substitute - unless you have amines or sulfides in your compound (it's pretty functional group tolerant otherwise). DMP is also used to cleave diols, whereas IBX cannot (in excess, IBX will just oxidise both of the hydroxys to carbonyls). I could go on for pages, really.

From what I've read, there are actually a few metabolic processes where substituting arsenic in place of phosphorous does result in the irreversible inhibition of certain enzymes. Off the top of my head I couldn't tell you which enzymes, but I do recall reading it when I was looking into that article I mentioned in my above post (the one about bacteria).

I don't know about this enzyme specifically, but arsenates can mimic phosphates in a lot of cases - and they do a good job of it too. Interestingly, a somewhat recent study in America found a species of bacteria that can substitute arsenic in place of phosphate and maintain themselves reasonably well. There was a thread on that study some time ago in the Science News section. Do you have access to a university library site or access to a scientific journal search engine? If so, you might find it quite helpful. If not, you should try using Google scholar or try finding a biochemistry text book.

On the topic of picric acid, a few years ago there was a couple of barrels of it found on the top level of the math/astrophysics building at uni. Been there for years. I like to think it was the doing of a very patient chemist, trying to knock mathematicians off from their position at the top of the heirachy with brute force. This is just in the same that way our chemistry building is specifically designed to explode outwards and take out maths, molecular biosciences and engineering, should it ever be blown up. The latter two are clearly just for fun.

Well, do you understand what the term, 'mole' refers to?

Ceribethlam, For future reference, try not to simply give out answers to what are clearly homework questions. Secondly, one of your answers was wrong. So if you are going to give help to people in chemistry in the future, please check you are giving correct advise. Qwerty, A few things you need to take notice of when doing these questions: The total ionic charge of a species is equal to the sum of the charges of its components. There are a few rules to pay attention to when working out the charge on each individual atom within a molecule. The major ones for you are that oxygen and hydrogen, when present as part of a compound, have charges of 2- and 1+ respectively. The exception for oxygen is in the case of peroxides (such as H2O2), where it has a charge of 1-. The other thing to remember is that molecular species, such as O2, N2 etc have a charge of 0. You can use this information quite to work out the charges of other species within a compound, or conversely, the net charge of the compound itself. As an example, if knowing that H and O have 1+ and 2- charge respectively, I can say that the net charge of a water molecule is 0. This is because the net charge of the compound is equal to the sum if the charges of it's components. Thus, the net charge of water = 2 [+1] (for the 2 hydrogens) + [-2] = 0. You could also work the reverse way to get the charge of say, oxygen, where you know the net charge of the compound it's in (water in this example, so 0). The correlations that ceribethlam made regarding which species were being oxidized and reduced were correct, but you need to watch for that peroxide in the last question. The oxygens in the permanganate are all 2-, but the peroxide oxygens are not. Hope the helps.

I don't agree so much with your little quip. Sure, there's an element of memorising at some point in the learning process, but that should only be for fundamental type processes. A more appropriate quote might have been, 'you can't abstract something unless you have something understood" . Memorising something is not the same as understanding something. For o. chem, curly arrows are a very simple way of achieving this. The more time you spend drawing them out, the more you can get a feel for how electrons move around and why. Simply, once you've got down why reactions occur, there is very little memory work necessary. As we have all said in one way or another, there are simply too many reactions in o. chem to memorise. There are of course aspects that are not so intuitive and things that you will need to learn. Generally though, it all comes back to one fundamental process or another. Anatomy has no instinctual logic behind it - it is all memory work. Organic chemistry, as I and others have stated, is a fairly intuitive branch of science once you have a grasp on the basics. And although I sound like a broken record by saying this, memorising reactions will serve you no good (in the long run) whatsoever. Finally, thinking about orbitals is definitely useful in a lot of cases - most notably in pericyclic chemistry and inorganic. However, you don't often have to consider vacant orbitals in much depth when looking at a reaction mechanism. With respect to the water as a leaving group - yes, to an extent, but there is a reason for why it is a good leaving group.

Geneks, I spend a lot of time tutoring first years in O. Chem here at my university. I can promise you that everything is so much easier and so much clearer if you can understand and draw curly arrows. Memorizing mechanisms, in my opinion, is pretty damn useless if you have no idea where the electons are going and why. It's the equivalent of memorizing the answer to a calculus question without actually knowing how to do calculus. I cannot stress enough how important it is for you to take some time out and read through a text book (McMurry and Clayden are good) and get a feel for curly arrows, what they mean and how to use them. If you can apply it to what you're learning in your class, it will do you a world of good. Memorizing reactions will not help you learn organic chemistry and what it's about.

No problems I figured it might not be, but it could very well be a helping hand to someone else in the future.

Hey, anything I can do to make people realise that O. Chem is really not as disgusting as undergrad sometimes makes it out to be, I will do to my fullest extent. The world needs more chemists, in my opinion

Understandable. They've certainly not made this easy for you. In the real world, we have 2D sepctra and our peaks are integrated, so don't get too scared away from organic chem. It's a pretty awesome subject, if I do say so myself

Horza2002 to the rescue!

I can see that ending in arrests and sexual offence charges; depending of course on if only one of both of them are deprived of the ability to recognise the other. Having said that, the latter case is nothing more than a tool for a wonderfully simple and clean cut divorce/break up.

It might just be me, but I can't see any spectra? Until I see it, I won't be much help because I would need to see the integration and Jz coupling constants. Just looking at what you've said for the 1H NMR, I'm not sure your integrations are right. Are you given an empirical formula or mass spec at all? Is your 13C spectra proton coupled or what? You don't normally get a proton coupled spectra without a decoupled one as well. Also, peak heights in 13C don't mean much of anything. Certainly not in the same way as in 1H NMR.

Well I think the wiki article fairly much answered your question. Essentially, given enough electrons and low-lying (in terms of energy) orbitals, it is possible.

Not true. I have ChemDraw on my mac and it works just fine Re. the OP. Are you looking for something that can model small compounds or protein type structures?

Not quite. Check your ChemDraw structures are correct. I drew all of your compounds in ChemDraw and got different names to the ones you listed here and the ones you say ChemDraw spat back. Very close to the ones you listed above, but your naming of the 'hydro' bits is wrong. Everything else is okay in 1a and b. In 2a and 2b, two of your stereochemistry assignments are wrong. 3a and 3b are not correct either. As I say, double check your drawings in ChemDraw are exactly the same as the picture you inserted in your OP. You should get your names right that way.

Certainly, there are cultural/environmental factors that influence whether a person becomes or is homosexual. However, that is not to say that there is not also a genetic predisposition or that a person's preferred sexual orientation is not a compounded result of the two.