The Periodic Table

@MAFIA36790 \o I'm just checking in :-) I have class in half an hour so I won't really be here for now

user116211

@Hippalectryon yeh... go ahead; have a rendezvous at the evening ;)

5:51 AM

@ToddMinehardt It's my pleasure. Thanks for understanding :D

DeNiSkA

6:15 AM

@Martin-マーチン is there any loss by deleting comments?

@DeNiSkA what do you mean? They are quite gone if you delete them - I can undelete only comments that a mod has deleted, but I can read all

DeNiSkA

@Martin-マーチン It means mods can see the deleted comments of random user?

mods can see every comment

DeNiSkA

oh!!

Q: What makes banana bonds possible in diborane?

9:39 AM

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Diborane has the interesting property of having two 3-centered bonds that are each held together by only 2 electrons (see the diagram below, from Wikipedia). These are known as "banana bonds." I'm assuming there is some sort of bond hybridization transpiring, but the geometry doesn't seem lik...

10:23 AM

@Hippalectryon the target and your product look like panduratin derivatives

10:34 AM

@Loong Yep that's (nearly) it! How did you find it ? I searched using all kind of identifiers and never found any result on pubchem/chemspider

A: Clear definition of a 'non-oxidizing acid'?

@Hippalectryon If you want to find great white sharks, look for the seals.

Or if you want to see cheetahs, look for Thomson's gazelles. ;-)

CowperKettle

@Freddy - I reposted your quote from Jespersen as an addon answer, hope you don't mind.

0

As an add-on, I'll post an excerpt from the 6th edition of "Chemistry: The Molecular Nature of Matter" by Jespersen et al. Kudos to Freddy who posted it in the chatroom.

O_o and where did you look for seals ? :-) I tried searching for the reagents, to no avail. I just used google and chemspider/.. though.

I.e., search the educts.

For example, google "2-bromo-5-methoxy-1,3-bis(methoxymethoxy)benzene" with quotes.

CowperKettle

Word of the day: educt

10:42 AM

ooh :D found it indeed. Unfortunately their way doesn't solve the position of the dienophile in my final product.

this structure is labelled 4-hydroxypanduratin A, but I don't think that the image is correct:

and of course, the cycloaddition yields a mixture of products:

researchgate.net/publication/…

Q: How to compare oxidizing power of perhalate ion(XO4-)

Well I'm not aiming for a great yield :D

Brian

11:06 AM

@Mart, should this Q be closed as duplicate?

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In my book the oxidizing power in descending order of the following is given as: BrO4-;IO4-;ClO4- I thought that chlorine has the highest electronegativity, so can help oxygen stabilize the -1 charge the best and be least raducing(electron donor) and most oxidizing. Looks like thats not the cas...

inorganic-chemistry

@ortho is right AFAICT: the reasoning behind the answer is (I think) the same as in the linked 'duplicate of' question.

But the question approaches the chemistry from a different property (abundance versus oxidizing power).

user116211

@Brian Does it answer?

user116211

If so, then definitely vc.

Brian

What's the policy here? Should the question be closed as duplicate? Or left open, and answered with a "the underlying reason is the same as in this question over here" -- lower stability of a high-oxidation state species means it will be a stronger oxidizer

@MAFIA36790 Sort of, but you have to make the logical link yourself that "lower stability of high oxidation state = stronger oxidizer". This new question has the potential to be found by people using different search terms.

My first reflex was vtc

Freddy

@cowper Great. No problem :-)

11:25 AM

@Brian & @MAFIA36790 Questions should only be closed as duplicates is the question is the same. There is no harm done in replicating an answer that is essentially the same and linking the two questions, if they are not the same question but deal with the same concept.

The reasoning behind this is mainly, that if you read the first question that will not get answers must be still recognisable in the second question which might have an answer. If they read completely different, then (especially) new users might not even bother to read the answers. Then they might get upset with how the community is treating these questions.

Brian

@Martin-マーチン Ok, that was what was leaning me in the non-vtc direction, yeah. Thanks!

@Jan is on the job, btw:

@orthocresol This is not a dupe, because it is not immediately apparant from the question that these will go in the same direction. For a dupe to be a dupe we need the essentially same answers and the essentially identical question. This one approaches the problem from a different angle. — Jan 9 mins ago

user116211

@Martin-マーチン oohhh... thanks mart.

No problem, happy to help out here ;)

user116211

Damn and there OP wants to catalogue ALL experiments that shaped the course of Physics......

user116211

WTF!! ;(

11:30 AM

@orthocresol You might want to earn a couple of more rep points by repeating the essential points in that new question ;)

Happy Anniversary everybody! A year ago Chemistry graduated. Let's have a high five for a job well done!

15

user116211

Well done mods.... for your never-ending work here @Mart and others....

oh... it will end ;)

CowperKettle

> Oh, mortal man may borrow What mortal man can lend; And 'twill not end tomorrow, Though sure enough 'twill end.

user116211

!!greet/@J.M.

Welcome to The Periodic Table @J.M.! Here are our chat guidelines and it's recommended that you read them. If you want to turn Mathjax on, follow the instructions in this answer. Happy chatting!

11:42 AM

@MAFIA36790 I have been here a number of times before, but thanks for the automatic thoughtfulness. ;)

To think that my oldest answer was during the last days of being a beta site *,…,*

@Jan "on the cusp", if you will.

orthocresol

@Martin-マーチン I commented on it. It's partly my fault I read too quickly - even the answer is not really the same because the question include Cl and I as well, but the last sentence left me with the impression that it was just Br that he was curious about

@orthocresol Well, that happens. And that's no problem. After all you let the community decide on it, that's why it says possible in the generated comment... no harm no foul. I think it helped in a way already :D

@Hippalectryon There is this rough rule in DA cycloadditions that the substituents in the resulting cyclohexene should exhibit a 1,2 or 1,4 relationship (I believe this is in Warren). You have a 1,3,5 configuration, so I am not optimistic about your proposal.

11:51 AM

@J.M. Do you have any idea how to do it then ? I have no idea without a D-A :(

@Hippalectryon nothing immediately comes to mind. the config is not amenable to a conjugation reaction, so I don't have any ideas at the moment.

Do you really have to use the protected phloroglucinol, or would you welcome other dissections?

Inb4 @PhMgBr calls dupe …

@PhyCS It's an experiment you can do: try soaking sand in soda water and report back. ;)

(P.S. HF is pretty much one of the few things that can chemically etch silica)

@J.M. Yeah I need to start from the three given reagents.

hmm, speaking of conjugation reactions, I quite like this drug:

!!img/ibrutinib

12:03 PM

@J.M. What about concentrated NaOH? ;p Also check out the glass cleaning answer. Brb finding it.

Q: Can I get notifications from my favourite tags into the SE inbox?

@Jan That takes longer, tho. :) Hence the injunction to never store concentrated bases in Pyrex for long periods.

Feeds meta.chemistry.se

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I’ve labelled a few favourite tags here (and more on other sites). I appreciate them being highlighted on the question page. Sometimes, however, I take breaks from Stack Exchange that can be anything between weeks and months. If any cool interesting question that uses my favourite tags happens t...

feature-request tags favorites

!!img/1-[(3R)-3-[4-Amino-3-(4-phenoxyphenyl)-1H-pyrazolo[3,4-d]pyrimidin-1-yl]-1‌-piperidinyl]-2-propen-1-one

12:05 PM

:(

:29630764 sadly, it does not seem to know the structure of that new wonder drug. But its structure is a very elegant biological application of Michael. :)

A: Cleaning a round-bottom flask, especially after distillation

15

@Permeakra suggests some good cleaning solutions. I have rearranged them (adding a few) in a suggested order from mildest to most evil. The specific thing you want to use will vary based on what you want to clean. If an initial rinse isn't good enough, you may want to let it soak for a few hours....

@Jan At the risk of revealing my age: Teepol is my favorite detergent for labware.

12:09 PM

I don’t even know what that is.

(Also, "Caro's acid" is a more dignified name than "piranha solution". ;P)

But piranhas!

@Jan It's an alkylbenzenesulfonate detergent Shell used to make.

After it was phased out, none of the detergents I've subsequently tried seemed to come close to the performance of Teepol.

Ah. I have yet to find a favourite detergent ^^

@Jan dishwasher + CTA

12:20 PM

@Jan That only happens after having to wash too many pieces of glass. (Where I was, experimentalists had to clean up after themselves, the rationale being that they were the only ones who knew how dangerous the leftover gunk in their glassware was)

@Loong Although our rule is:

> First you clean it, then you give it to the cleaning staff for the dishwasher.

It does look like an untapped market: lab-hardened dishwasher

Up to this day, I still chuckle at the memory of seeing a Sigma-Aldrich vending machine.

@Jan yeah, I usually boiled my PFA beakers in HCl + HNO3 and then removed the acid with pure water before they went into the dishwasher, mainly to prevent cross-contamination

user116211

12:54 PM

in The h Bar, 11 mins ago, by MAFIA36790

BTW, hasn't the mobile site changed its appearance?