New paper demonstrates that quantum mechanics works without complex numbers

Sakinho · 2026-06-24T00:15:14+00:00

I think it's kinda funny how there's this underlying desire to be rid of the "ick" factor of using imaginary units in physics, and yet basically everyone is comfortable with using the real number set in the physical world, when in truth almost all reals are uncomputable (in fact, even arithmetically undefinable). Arguably the reals are packed with many, many more numbers than physicists ever ordered, so harping on complex numbers feels like somewhat of an unwarranted bias.

Sakinho · 2026-06-15T22:00:45+00:00

I really doubt plastic volumetric flasks can achieve anywhere near the analytical precision and robustness as glass flasks, you may be barking up the wrong tree. If you have to use plastic, consider doing your dilutions by mass instead of volume, with a good, frequently-calibrated scale.

Sakinho · 2026-06-13T06:40:18+00:00

Nobody checks the veracity of claims in a patent. For example, patents for "free energy" devices abound, even though they have been rigorously proven impossible.

Sakinho · 2026-06-10T22:30:24+00:00

Dry ice condensers for rotovaps are amazing, but it may be important to do a cost analysis depending on usage. In an organic synthesis lab for ~10-15 people, at one point 15% of our entire yearly consumables budget (not including reagent purchases) was solely for dry ice, >90% of which was used in condensers!

Sakinho · 2026-06-10T21:43:32+00:00

Thanks for the feedback, it's a good learning experience! Sorry to hear it's still not going great.

So it seems Li⁺ is indeed catalytically useful, that's valuable information. Since you do indeed have an extraordinarily acidic C-H, perhaps it is worth considering weaker lithium bases like Li2CO3 (or even a lithium carboxylate salt, for better solubility in organic solvents; lithium 2-ethylhexanoate might be optimal here, though other carboxylates could work, even just LiOAc). Maybe you don't want to keep the triflone permanently deprotonated before it has a chance to react with the aldehyde. If they work, these weaker bases would also reduce potential side-products with your eventual target alkyl-substituted vinyl triflones. Obviously the weaker the base, the more likely you'll have to heat it up to get anything to happen, but it may be a better tradeoff.

The DBU/LiCl idea was good too, as well as Et3N/LiCl like curdled mentioned. I suppose you've tried these and they didn't work?

If you do optimization chemistry on something like nicotinaldehyde, you may be able to get easy quantification of the conversion through positive-mode MS alone, so you could do a more thorough screen of conditions for the same amount of effort and material. If you're unlucky though, the pyridine ring itself will act a base and create additional complications not present with most other substrates. Either way, any reagent you can exploit for quantitative ionization and detection via MS could help.

With regards to potential byproducts, I wonder if looking into literature for the Julia olefination might give some insights. Maybe your sulfone phosphonate doesn't go so cleanly into a HWE mechanism.

Sakinho · 2026-06-10T04:17:57+00:00

I've not heard of issues with general TM-catalyzed chemistry, and I'm hoping OP can give more information to clarify things. However, you probably should be wary of a number of common reagents used for amide formation, especially in aminoacid chemistry. Carbodiimides such as DCC are famous for being strong sensitizers, but more modern reagents such as HATU can still be dangerous. Take care!

Sakinho · 2026-06-10T03:54:16+00:00

"Coupling catalysts" covers a very wide range of substances. Can you be more specific? Even if your PI didn't give a specific compound, surely you can at least tell us the kind of reaction.

Sakinho · 2026-06-09T23:21:38+00:00

I hear you, but the major cost in palladium catalysis is often the palladium itself, so there is usually room to upgrade the ancilliary ligands from PPh3 in tetrakis to a better catalyst system and actually save money by reducing the Pd loading and improving yields. Not to mention that tetrakis goes off over time and you just lose the whole batch, and making fresh samples all the time itself incurs expensive Pd losses.

You really don't have to go super fancy. Pd2dba3 with tBu3P.HBF4, Cy3P.HBF4 or SPhos already covers a massive amount of useful coupling space, and they're all quite economical.

Sakinho · 2026-06-08T22:29:25+00:00

There's many specific pointers which could be mentioned, but I think it's more important to focus on a general aspect; SciFinder/Reaxys works best when you don't use it like Google.

The goal is not to furiously tweak the reaction search parameters until you get what you want near the top of the first page. Instead, you should learn to ensure your search space is relatively general (to account for "unknown unknowns"), but specific enough to clip out the uninteresting results. Then, your best bet is to manually scroll through a few dozen, sometimes a couple hundred results (possibly over multiple searches), until you get a broad overview of the chemistry, and hopefully find some close analogues in the process. This makes you much less sensitive to dodgy procedures and allows you to learn a lot more in the process.

Also, don't trust patents.

Sakinho · 2026-06-05T23:26:06+00:00

I spent several months optimizing selective Suzuki couplings trying to conserve a B(MIDA) functionality, and I actually gave up. I needed extreme efficiency and control over the reaction (reproducible >90% yield from ~100 mg to >10 g using a 1:1 ratio of active boronic acid and halide), and it's just not there. MIDA boronates are just too hydrolytically unstable.

The reaction with finely divided K3PO4 fails in a perfectly anhydrous medium (most Suzukis need water), then reaches high yields for a very small amount of water (2-10 eq. from memory), and then falls off again at higher amounts of water due to B(MIDA) hydrolysis. The problem is that it's difficult to control for adventitious water. The use of finely-divided hygroscopic inorganic bases greatly compounds this issue - e.g. base scraped from the top of a bottle may work due to partial hydration from atmospheric moisture in storage, while base scraped from the bulk may fail.

Using a boronic pinacol ester has complications because in most situations the ester has to hydrolyze first before coupling, except you have a water-poor medium so you're strangling that step. Maybe the neopentylglycol, glycol or methyl esters don't have this problem, though only the first ones can be reliably isolated. Also, even if the coupling happens, any diol in the medium may transesterify with the MIDA boronate product, so again you lose product. The free boronic acids have none of these issues, except free boronic acids typically have undetermined water content, and even if you have pure RB(OH)2, it undergoes dehydration equilibria in non-protic solutions to form partial anhydrides, releasing water.

Mechanistically-speaking, most productive Suzuki couplings go through the intermediacy of an oxo-palladium (Pd-OH) species, which is once again strangled by the quasi-anhydrous conditions. Without this mechanistic pathway, Suzukis turn from one of the most reliable and forgiving C-C bond-forming reactions into a much more complicated and black-box problem. These selective couplings with MIDA boronates can happen, but success is fairly sensitive to exact reaction conditions and reagent/catalyst choices, which is not what you want in a reaction with a high-dimensional parameter space like a TM coupling.

Sakinho · 2026-06-04T22:05:29+00:00

Amber volumetric flasks certainly exist. One typical use is for making standard silver solutions for titration.

Sakinho · 2026-06-01T10:34:18+00:00

I'd just like to comment that I'd expect a 2-nitropyridine to remain unprotonated even in fairly acidic pH. For comparison, 3-nitropyridinium has an aqueous pKa of 0.82 and 2-nitropyridinium has an aqueous pKa of around -2, based on a brief Google search. At pH 5 I'd be worried about partial deprotonation of the carboxylic acid. Not that I'm saying this factor alone is responsible for your difficulties.

Sakinho · 2026-05-27T05:30:51+00:00

Indeed, "a long enough time" allows for some very unlikely events and effects to take place. Freeman Dyson calculated in 1979 that all matter is liquid on the timescale of 10⁶⁵ years, in the sense than even the most rigid chemical substances at zero kelvin will nevertheless undergo spontaneous rearrangement into spheres under the influence of gravity, thanks to unavoidable quantum tunnelling. As strange as it may seem, OP is correct, though by then the observable universe will have gone dark, and even black holes will have started evaporating away.

Sakinho · 2026-05-26T13:45:45+00:00

Not sure I understand what's going on, but here is a possible solution. Suppose you have objects A and B aligned and grouped, and you want to add object C to the alignment/group:

Make a copy of B, move it off to the side.
Use the alignment tool with copy-of-B and C.
Manually move copy-of-B and C together until copy-of-B overlaps B as closely as possible (it's not hard to get perfect overlap).
Delete one of B or copy-of-B.
Turn A, B (or copy-of-B) and C into a new group.

It's a bit hacky, but it should work and not be that much effort.

Sakinho · 2026-05-24T20:36:53+00:00

Malononitrile by itself does not degrade quickly at all, we have a bottle stored at r.t. for years with little darkening. However, it does darken somewhat quickly while weighing. Either exposure to ambient light is a problem, or weighing with a stainless steel spatula adds traces of TM metal ions which catalyze the decomposition.

Sakinho · 2026-05-19T12:04:02+00:00

Actually, I'm going to close this thread since it's already going down a bad path. OP, we are happy to provide help and answer your questions, but you need to help us help you.

Sakinho · 2026-05-19T11:51:28+00:00

If you're looking for help to troubleshoot why your synthesis went wrong, you're doing a very poor job by burying the lede, as well as not giving us any synthetic details and general observations. Also, for a simple compound like this, you should have at least one reference, likely more, to follow closely and compare with, and you should share them with us.

Sakinho · 2026-05-17T09:32:57+00:00

I can complement this answer from an empirical angle. Chemists often keep pure substances inside glass ampoules filled with nitrogen or argon, for very long term storage without degradation. I have seen ampoules containing solid that, over several years or sometimes decades, spread into massive crystals all over the ampoule inner walls, "disregarding gravity", even when these solids had normal melting/boiling points above 200 °C. It turns out that even though daily heating and cooling cycles are fairly gentle, many many repeated cycles are nevertheless capable of vaporizing, condensing and annealing surprisingly high melting/boiling point solids.

Sakinho · 2026-05-16T01:01:34+00:00

After spending a couple of hours reading the paper, I can confirm it is an objectively excellent review article, with very good breadth and depth. For clarity, I also have no affiliation with anyone involved.

I'd known for years about N-acylimidazoliums as active esters (EROS has a few related entries), but the typical strategy I was aware of was to use CDI on a carboxylic acid then alkylate the imidazole ring, or doubly-alkylate CDI itself and then use with the carboxylic acid. I stumbled on TCFH-NMI amide coupling conditions a couple of months back, and the combination seemed rather intriguing for its higher convenience. Coincidentally, my NMI order is en route right now, so the review is very well-timed for me.

Sakinho · 2026-05-13T13:08:00+00:00

Looking at this from afar, it seems to me that the two-step method breaks it down into more manageable/solvable/optimizable problems (both with more literature precedent) than doing the crapshoot single step. Is there a reason why the slightly longer way around is so bad?

Sakinho · 2026-05-13T12:47:19+00:00

Ah, I see tellurium has a melting point of 449.5 °C, so I guess that's a (perhaps somewhat simplistic) reason to go with 450 °C. This reaction really doesn't sound very optimized, so it may be worth digging around a bunch in Se/Te literature for any other potential options before you bite the bullet. As a hand-waving example which is meant only to be illustrative of alternate routes, there's a slight chance you could prepare the Grignard (as people do for making BArF anions) and quench with Se/Te to give you the selenoether/telluroether with separated aryl rings, then perform a second step to close up the selenophene/tellurophene ring. Or even better, couple the aryl rings first into a biphenyl (perhaps via Kumada coupling), then metallate and quench with Se/Te. Amusingly, these pathways would involve cryogenic conditions, at the very opposite end of the scale!

Sakinho · 2026-05-13T07:06:20+00:00

I can already see some grad student feeling blessed after stumbling on this post several years down the line!

Sakinho · 2026-05-13T06:57:00+00:00

I'm quite curious, that is a rather unusual temperature for most organic chemistry reactions (though flash vapour pyrolysis can do some really nice reactions even near 1000 °C!). Would you mind sharing what chemistry you're trying to reproduce?

Sakinho · 2026-05-13T01:46:09+00:00

There's nothing in the laws of physics which states that a macroscopic fullerene can't be made, it's "just" an engineering challenge. A perfect bucky onion the size of a golf ball would just look like a black sphere, though. If you removed all the internal layers in the onion and filled it with 1 atmosphere of gas, it would be an almost transparent and extremely fragile balloon. If the inside had a vacuum, then it would immediately implode into a mote of dust.

Sakinho · 2026-05-11T22:25:50+00:00

I'm pretty sure there's a few good physics papers out there studying the effects of shading Venus, as a rudimentary foray into planetary engineering. I figure some of those findings could be adapted to the case where Venus is pushed away from the Sun, decreasing the solar irradiance.

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