Archive for the ‘Interesting chemistry’ Category
Friday, April 13th, 2018
In several posts a year or so ago I considered various suggestions for the most polar neutral molecules, as measured by the dipole moment. A record had been claimed[1] for a synthesized molecule of ~14.1±0.7D. I pushed this to a calculated 21.7D for an admittedly hypothetical and unsynthesized molecule. Here I propose a new family of compounds which have the potential to extend the dipole moment for a formally neutral molecule up still further.
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References
- J. Wudarczyk, G. Papamokos, V. Margaritis, D. Schollmeyer, F. Hinkel, M. Baumgarten, G. Floudas, and K. Müllen, "Hexasubstituted Benzenes with Ultrastrong Dipole Moments", Angewandte Chemie International Edition, vol. 55, pp. 3220-3223, 2016. https://doi.org/10.1002/anie.201508249
Tags:aromatisation stabilization energy, Chemical polarity, chemical properties, Chemistry, Dipole, Electric dipole moment, Electromagnetism, energy, Moment, Nature, Physical quantities, Physics, Potential theory
Posted in Interesting chemistry | 11 Comments »
Sunday, March 18th, 2018
Around the time of the 2012 olympic games, the main site for which was Stratford in east London, I heard a fascinating talk about the “remediation” of the site from the pollution caused by its industrial chemical heritage. Here I visit another, arguably much more famous and indeed older industrial site.
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Tags:City: London, Environment, Environmental Issues, Environmental toxicology, Geography of London, industrial chemical heritage, industrial site, London Borough of Newham, London boroughs, Pollution, Province/State: Swansea, Queen Elizabeth Olympic Park, river Tawe, Stratford, Stratford London, Stratford station, Summer Olympics, the 2012 olympic games, unfortunate by-product, William Blake
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Wednesday, March 7th, 2018
C&EN has again run a vote for the 2017 Molecules of the year. Here I take a look not just at these molecules, but at how FAIR (Findable, Accessible, Interoperable and Reusable) the data associated with these molecules actually is.
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Tags:Carotenoids, Chemistry, Epoxides, Macrocycles, Organic chemistry, Organofluorides, PDF, Peptides, search engine, search program, search.datacite.org search engine, Technology/Internet
Posted in Chemical IT, crystal_structure_mining, Interesting chemistry | No Comments »
Sunday, March 4th, 2018
A bond index (BI) approximately measures the totals of the bond orders at any given atom in a molecule. Here I ponder what the maximum values might be for elements with filled valence shells.
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Tags:Atom, Chemical bond, chemical bonding, chemical properties, Chemistry, metal bond indices, Molecule, Nature, Quantum chemistry, Residential REITs, Resonance, Tennessine, Valence, Valence electron
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Friday, February 23rd, 2018
A little while ago I pondered allotropic bromine, or Br(Br)3. But this is a far wackier report[1] of a molecule of light.
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References
- Q. Liang, A.V. Venkatramani, S.H. Cantu, T.L. Nicholson, M.J. Gullans, A.V. Gorshkov, J.D. Thompson, C. Chin, M.D. Lukin, and V. Vuletić, "Observation of three-photon bound states in a quantum nonlinear medium", Science, vol. 359, pp. 783-786, 2018. https://doi.org/10.1126/science.aao7293
Tags:Atomic physics, Bromine, Bromine compounds, chemist, Chemistry, Halogens, Hypobromite, Oxidizing agents
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Saturday, January 6th, 2018
The title here is from an article on metalenses[1] which caught my eye.
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References
- M. Khorasaninejad, W.T. Chen, A.Y. Zhu, J. Oh, R.C. Devlin, D. Rousso, and F. Capasso, "Multispectral Chiral Imaging with a Metalens", Nano Letters, vol. 16, pp. 4595-4600, 2016. https://doi.org/10.1021/acs.nanolett.6b01897
Tags:Biochemistry, Biology, Chemistry, Chirality, Circular dichroism, Nature, Pharmacology, Polarization, spectroscopy, Stereochemistry, Ultraviolet, Vibrational circular dichroism
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Saturday, December 23rd, 2017
In the previous post, I referred to a recently published review on hypervalency[1] which introduced a very simple way (the valence electron equivalent γ) of quantifying the effect. Diazomethane was cited as one example of a small molecule exhibiting hypervalency (on nitrogen) by this measure. Here I explore the effect of substituting diazomethane with cyano and nitro groups.‡
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References
- M.C. Durrant, "A quantitative definition of hypervalency", Chemical Science, vol. 6, pp. 6614-6623, 2015. https://doi.org/10.1039/c5sc02076j
Tags:candidate for hypervalent carbon, chemical bonding, Hypervalent molecule, Molecular geometry
Posted in Hypervalency, Interesting chemistry | No Comments »
Saturday, December 2nd, 2017
For around 16 years, Floyd Romesberg’s group has been exploring un-natural alternatives (UBPs) to the Watson-Crick base pairs (C-G and A-T) that form part of the genetic code in DNA. Recently they have had remarkable success with one such base pair, called X and Y (for the press) and dNaMTP and d5SICSTP (in scholarly articles).[1],[2] This extends the genetic coding from the standard 20 amino acids to the possibility of up to 172 amino acids. Already, organisms engineered to contain X-Y pairs in their DNA have been shown to express entirely new (and un-natural) proteins.
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References
- A.W. Feldman, M.P. Ledbetter, Y. Zhang, and F.E. Romesberg, "Reply to Hettinger: Hydrophobic unnatural base pairs and the expansion of the genetic alphabet", Proceedings of the National Academy of Sciences, vol. 114, 2017. https://doi.org/10.1073/pnas.1708259114
- D.A. Malyshev, K. Dhami, H.T. Quach, T. Lavergne, P. Ordoukhanian, A. Torkamani, and F.E. Romesberg, "Efficient and sequence-independent replication of DNA containing a third base pair establishes a functional six-letter genetic alphabet", Proceedings of the National Academy of Sciences, vol. 109, pp. 12005-12010, 2012. https://doi.org/10.1073/pnas.1205176109
Tags:Base pair, Biology, DNA, Floyd Romesberg, Gene, genetic code, Genetics, Molecular biology, Molecular genetics, Nucleic acids, Nucleotide, Synthetic genomics
Posted in Interesting chemistry | 3 Comments »