Henrik Ottosson

A molecule with half-Möbius topology Stereoisomers of C13Cl2 exhibiting helical orbitals around a ring of carbon atoms were synthesized by atom manipulation on NaCl surfaces. We resolved the enantiomeric geometries of the singlet states ...

We did some pretty twisted stuff and Science liked it: www.science.org/doi/10.1126/...

Aromatic Interactions Select for Homodimeric Assembly in a Quadruply Hydrogen-Bonded DADA 1,2-Azaphosphinine Dimer Inclusion of a fused pyridine ring onto the core motif of an azaphosphinine heterocycle, as well as functionalization with an N-acetamide group, furnishes a chiral, quadruple hydrogen bonding face that is capable of strong homodimerization. Eleven different azaphosphinine derivatives were prepared with variable electron donor and acceptor functionalization. Contrary to simple DA azaphosphinine dimers, trends from substituent effects showed that the hydrogen bond acceptors (A) were more sensitive to the substituents than the hydrogen bond donors (D). With electron donating groups appended onto the azaphosphinine scaffold, dimerization constants rose to as high as 209 M–1 in 10% DMSO-d6 in water-saturated CDCl3. X-ray crystallographic data unexpectedly showed that the quadruply hydrogen bonding system preferred the theoretically less stable donor–acceptor–donor–acceptor (DADA) H-bond orientation despite having the capability to tautomerize to the potentially more stable DDAA structure. Computational analysis revealed that maintaining pyridine aromaticity was more stabilizing than the secondary interactions that would be created from a DDAA dimer. Additionally, these molecules associate as the first examples of R,R- and S,S-azaphosphinine homodimers, compared to the R,S-heterodimers typically found for simple azaphosphinines. This observation was explained by computational analysis, which found a geometric difference between the nitrogen atoms adjacent to the phosphorus chiral center of the Homo and Hetero dimer, leading to a stronger hydrogen bonding interaction in the Homo dimer. Further understanding of this quadruply hydrogen bonding core will allow us to explore further applications that integrate this strongly hydrogen bonding system into larger and more complex supramolecular frameworks such as supramolecular polymers or capsules.

At long last—a GREAT effort by Megan & Nolan finally out in JACS after a 2+ year gestation. We found quadruply hydrogen-bonded DADA azaphosphinine homodimers are preferred over the theoretically more stable DDAA dimers, and they possess STRONG homodimerization constants.
pubs.acs.org/doi/full/10....

🔈 We've extended the deadline for nominations for the 2026 Chemical Science Lectureship to 13 March. So keep sending those nominations to us!
See rsc.li/chemsci-lectureship26 for details about eligibility and how to nominate.
#CompChem #MLChem #AIChem #MachineLearning

Deciphering the molecular origin of the 19.3 eV electronic excitation energy of H3+ The trihydrogen cation, H3+, is unique in the Universe. It serves as the primary proton reservoir, driving essential astrochemical reactions, and it functions as a thermostat for giant gas planets. H3...

The smallest and most abundant aromatic species in the Universe, H3+, has some truly crucial functions. It also has a really high first electronic excitation energy; 19.3 eV. Check out why this is the case in our latest paper in @chemicalscience.rsc.org pubs.rsc.org/en/content/a...

with lectures by Irene Casademont, @ironcevic.bsky.social, Bo Durbeej, Debashree Ghosh, Mercedes Alonso Giner,
Victor Gray, Juwon Oh, Josene Toldo, Igor Alabugin and myself.

The slides at the Winter School of icesaa-4.in are now available to download; in total 388 slides on intro (anti)aromaticity & descriptors, intro photochemistry, ultrafast spectroscopy, computations of excited states, excited state PES features, organic photochem & pitfalls ...🧵

Unhinged

Please remember to block September 22 - 25, 2027, in your calendar for ICESAA-5 to be held in Osaka, Japan, by Prof. Shohei Saito & team. More info to be posted in the next few months, yet be prepared, it will also be a really stimulating conference!!!

Here the conference photo at the 4th International Conference on Excited State Aromaticity & Antiaromaticity @icesaa-4.bsky.social held at IISER-TVM on Jan 8 - 11. An absolutely fantastic conference - thanks a lot @maheshhariharan.bsky.social & team!!!

History shows that when institutions fail, democratic protest in streets & squares is the last safeguard of democracy. This raises a pressing question about the United States: where’s the popular mobilisation? The Trump admin, marked by oligarchic influence, set an alarming benchmark for corruption.

The Polish prime minister reacts

Most dismaying is the lack of imagination. How sad to equate freedom for sitting alone in a private, movable metal cell—a.k.a. car—and then spend most time in a long row of these cells—a.k.a. traffic jam? And how many people r even truly noticing the few genuine freedoms that car can actually offer?

Hand in a bookshop holding a hardcover book called Life after cars. It has a traffic sign yellow border and drawn cover art of a yellow traffic signal that has been overrun by vining and flowering plants.

I biked two blocks over to my local train depot and picked this gem up from the independent bookshop therein. It was a good place to imagine a #LifeAfterCars.

@thewaroncars.bsky.social

Quantum tunnelling drives aromaticity flip-flop Augmented pentalene structure could be a molecular Schrödinger's cat, aromatic and antiaromatic at the same time

Researchers have discovered molecules where individual rings can flip between aromatic and antiaromatic states so rapidly that they could exist in quantum superposition – creating a molecular equivalent of Schrödinger's cat.

This Chemistry World is covering the work of @kozuchsebastian.bsky.social, published in Chemical Science.

You can read the full paper here:
doi.org/10.1039/D5SC...

#ChemSky

Note: Several have had problems to pay the registration fee for participation at ICESAA-4. If you are among these, please note that it is possible to pay by card on-site. Further information is available at icesaa-4.in/registration New registration deadline is Oct 20.

In 1933, the Athens Charter set the stage for modern urbanism through zoning — a vision led by Le Corbusier.
That vision shaped cities around the world, but today we must rethink its legacy.
The city of the future must be connected and human-centered.

Canon.

Sharing new work. Now on @ChemicalScience on how geminal hyperconjugation affects heavy-atom tunneling! pubs.rsc.org/en/content/a...

Car-dependent suburban sprawl is the most publicly expensive, publicly subsidized, and publicly consequential form of human habitation in human history. #SuburbanSprawl #CarDependency

⏳ Don’t miss out! ICESAA-4 registration closes soon – secure your spot today and be part of cutting-edge science in action. 🔬✨Last date: Aug 30, 2025. Late registration closes: Sep 30, 2025. #ICESAA4 #ScienceConference #Research"

REMINDER of deadlines for ICESAA-4 in Kerala, India:
Early-bird registration deadline: Aug 30
Abstract submission deadline: Sept 15
Regular registration deadline: Sept 30
This is the conference to attend if you want to learn about excited state aromaticity & antiaromaticity, at a wonderful place!

“The guy Trump nominated to lead the Bureau of Labor Statistics at January 6, amazing scoop by Ryan Reilly”
(HT Aaron Fritschner)
www.nbcnews.com/politics/jus...

The same forces that have destroyed Sudan are coming for other countries, @anneapplebaum.bsky.social reports. Greed, nihilism, and transactionalism are reshaping the politics of the rich world—and as the liberal world order falls away, there’s nothing to replace it: https://theatln.tc/QFUVKQg3

Toward a Systematics for the Lowest Excited States of Heteroaromatics Enabled via Cyclic π-Conjugated Carbenes and Heteroelement Analogues The photochemistry of heteroaromatic compounds depends on the character of their lowest electronically excited states, which are of either n,π* or π,π* type. For species with 4n + 2 π-electrons, the l...

Now in the special issue on Physical Organic Chemistry of
J. Org. Chem.. We explore which factors determine whether a certain heteroaromatic compound has its first excited states (T1 & S1) of npi* or pipi* character, and identify six factors. More to follow!
pubs.acs.org/doi/10.1021/...

Chemistry artwork by Toma Bohmick

Super inspiring talk by Stefan Hecht. ”There is no applied science without science to apply”

Stable Tribrominated Phenalenyl Radical Exhibiting Long-Lived Luminescence from a Monomer−π-Dimer Equilibrium Open-shell organic radicals exhibit exceptional photophysical properties due to their unique electronic structures. Herein, we report the 2,5,8-tribromophenalenyl radical (Br-PLY) as a stable, emissive phenalenyl derivative. Br-PLY shows a monomer−π-dimer equilibrium in solution and emits light from its monomeric radical state. Its high air stability (t1/2 ≈ 40 h) and long-lived emission (τ = 252 ns) demonstrate the potential of phenalenyl radicals as promising luminescent materials beyond trityl-based systems.

Congratulations to our PostDoc Marvin on his newest publication from his time in the Kubo Lab! 🤩👨‍🔬
Read all about it below👇 #chemsky #pisky #postdoc

pubs.acs.org/doi/full/10....

Molecular belts can go SUPERCOILED! An amazing 24-benzene and 24-thiophene fused molecular belt with a plectonemic geometry.
x.com/kelong_zhu/s... #PiSky