A breakthrough study has validated the existence of a stable single-electron covalent bond between two carbon atoms, supporting Linus Pauling’s early 20th-century theory and opening avenues for chemical research.
Covalent bonds, in which two atoms share a pair of electrons, form the foundation of most organic compounds. In 1931, the Nobel Laureate Linus Pauling suggested that covalent bonds made from just a single, unpaired electron could exist, but these single-electron bonds would likely be much weaker than a standard covalent bond involving a pair of electrons.
Since then, single-electron bonds have been observed, but never in carbon or hydrogen. The search for one-electron bonds shared between carbon atoms has stymied scientists.
Experimental Breakthrough in Chemical Bonding
Now, a team of researchers from Hokkaido University has isolated a compound in which a single electron is shared between two carbon atoms in a remarkably stable covalent bond, known as a sigma bond. Their findings are published in the journal Nature.
“Elucidating the nature of single-electron sigma-bonds between two carbon atoms is essential to gain a deeper understanding of chemical-bonding theories and would provide further insights into chemical reactions,” explains Professor Yusuke Ishigaki of the Department of Chemistry at Hokkaido University, who co-authored the study.
The single-electron bond was formed by subjecting a derivative of hexaphenylethane, which contains an extremely stretched-out paired-electron covalent bond between two carbon atoms, to an oxidation reaction in the presence of iodine. The reaction produced dark violet-colored crystals of an iodine salt.
The team used X-ray diffraction analysis to study the crystals and found that the carbon atoms in them were extremely close together, suggesting the presence of single-electron covalent bonds between carbon atoms. They were then able to confirm this using a form of chemical analysis called Raman spectroscopy.
Implications and Future Research
“These results thus constitute the first piece of experimental evidence for a carbon-carbon single-electron covalent bond, which can be expected to pave the way for further developments of the chemistry of this scarcely-explored type of bonding,” Takuya Shimajiri, the lead author of the paper and now at the University of Tokyo, says.
Reference: “Direct evidence for a carbon–carbon one-electron σ-bond” by Takuya Shimajiri, Soki Kawaguchi, Takanori Suzuki and Yusuke Ishigaki, 25 September 2024, Nature.
DOI: 10.1038/s41586-024-07965-1
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11 Comments
The arrangement of electrons in the nucleus and their combination caused the emergence of elements. This is a very strange and complicated issue. Most of the plants were created from oxygen and the disintegration of hydrogen
Less doubt is present that,certain long streached C – C bond on reaction with one-electron oxidation of hydrocarbon,can result a carbon-carbon one-electron sigma-bond,verified through calculation of energy equation.
Here,for calculation of energy of a bond;must follow the condition of a neutral molecule,present in the ground state.So,any extra energy,as due to stretching of bond can be accounted for differently to balance the equation of energy in a chemical reaction as usual for reactant and product,both sides.
He was right about the vitamin C, too, yet the media branded him a quack.
More importantly, biochemist Pauling was wrong on medicine and his peers called him out on it.
“In his later years, he promoted nuclear disarmament, as well as orthomolecular medicine, megavitamin therapy,[11] and dietary supplements, especially ascorbic acid (commonly known as Vitamin C). None of his ideas concerning the medical usefulness of large doses of vitamins have gained much acceptance in the mainstream scientific community.”
Where is your Noble prize since you fancy yourself as expert. Maybe you work for the big greedy pharmacuetical companies.
Question ? Is the bonding of this natural only in a biological electron pair or could the process be the same in electron bonding of how charged atoms transfer the charge in an electrical wires edge effect.
The one-electron covalent bond – if that is what it is, I think the jury is still out on the definition of covalent bonds – seems only appear in contrived situations.
Metal wires conduct valence electrons differently.
“In order for current to flow within a closed electrical circuit, one charged particle does not need to travel from the component producing the current (the current source) to those consuming it (the loads). Instead, the charged particle simply needs to nudge its neighbor a finite amount, who will nudge its neighbor, and on and on until a particle is nudged into the consumer, thus powering it. Essentially what is occurring is a long chain of momentum transfer between mobile charge carriers; the Drude model of conduction describes this process more rigorously. This momentum transfer model makes metal an ideal choice for a conductor; metals, characteristically, possess a delocalized sea of electrons which gives the electrons enough mobility to collide and thus affect a momentum transfer.” https://en.wikipedia.org/wiki/Electrical_conductor
“The Drude model attempts to explain the resistivity of a conductor in terms of the scattering of electrons (the carriers of electricity) by the relatively immobile ions in the metal that act like obstructions to the flow of electrons.
The model, which is an application of kinetic theory, assumes that the microscopic behaviour of electrons in a solid may be treated classically and behaves much like a pinball machine, with a sea of constantly jittering electrons bouncing and re-bouncing off heavier, relatively immobile positive ions.”
https://en.wikipedia.org/wiki/Drude_model
Question ? Could this action of biological pairing electrons be paired in example to the human sensing with a touch . Seems like a lot of different actions could be explained similarly but in different aspects.
Neurons and specifically sensory neurons works through action potentials – changing membrane potentials – and as one could expect of a fluid system it is ions and not electrons that do most of the work.
“As an action potential (nerve impulse) travels down an axon there is a change in electric polarity across the membrane of the axon. In response to a signal from another neuron, sodium- (Na+) and potassium- (K+)–gated ion channels open and close as the membrane reaches its threshold potential. Na+ channels open at the beginning of the action potential, and Na+ moves into the axon, causing depolarization. Repolarization occurs when K+ channels open and K+ moves out of the axon, creating a change in electric polarity between the outside of the cell and the inside. The impulse travels down the axon in one direction only, to the axon terminal where it signals other neurons.” https://en.wikipedia.org/wiki/Action_potential
“Sensory neurons, also known as afferent neurons, are neurons in the nervous system, that convert a specific type of stimulus, via their receptors, into action potentials or graded receptor potentials.[1] This process is called sensory transduction.” https://en.wikipedia.org/wiki/Sensory_neuron
That said, the specific mechanisms of sensory neurons are many and complicated and e.g. membrane bound electron transport chains also appears in organisms – but mainly for metabolic purposes.
“An electron transport chain (ETC[1]) is a series of protein complexes and other molecules which transfer electrons from electron donors to electron acceptors via redox reactions (both reduction and oxidation occurring simultaneously) and couples this electron transfer with the transfer of protons (H+ ions) across a membrane. Many of the enzymes in the electron transport chain are embedded within the membrane.”
“In eukaryotic organisms, the electron transport chain, and site of oxidative phosphorylation, is found on the inner mitochondrial membrane. The energy released by reactions of oxygen and reduced compounds such as cytochrome c and (indirectly) NADH and FADH2 is used by the electron transport chain to pump protons into the intermembrane space, generating the electrochemical gradient over the inner mitochondrial membrane. In photosynthetic eukaryotes, the electron transport chain is found on the thylakoid membrane. Here, light energy drives electron transport through a proton pump and the resulting proton gradient causes subsequent synthesis of ATP. In bacteria, the electron transport chain can vary between species but it always constitutes a set of redox reactions that are coupled to the synthesis of ATP through the generation of an electrochemical gradient and oxidative phosphorylation through ATP synthase.[3]” https://en.wikipedia.org/wiki/Electron_transport_chain