Best Chemistry Discoveries (Jan-Feb, 2021)

Scientists and researchers throughout the world are working restlessly and reporting their research outcomes every day in various journals. Every month thousands of such research reports are being published in different journals worldwide. A novel discovery happens after extreme hard work, application of knowledge and serendipity, and a long-term effort. After scanning basic to critical research efforts reported in top journals, we summarized the 7 best chemistry discoveries of the month (Jan-Feb, 2021).

Artificial Intelligence in Chemistry that makes Reaction Optimization is Easier than Ever!

Two scientists from Princeton University (USA), Prof. Abigail G. Doyle (Department of Chemistry) and Prof. Ryan P. Adams (Department of Computer Science) collaborated together to develop a reaction optimization software that is capable to produce more accurate results than human experts.

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Reaction optimization is the major area that delays the development of a synthetic methodology. Often some critical reactions remain unsolved when scientists fail to figure out the suitable ligands, catalyst, solvent, or additives.

Prof. A. G. Doyle, Prof. R. P. Adams, and their groups adopted the key principles of Bayesian Optimization (BO) to discovered the “state-of-the-art global optimization algorithm”. According to them, this system can find out unexpected reaction conditions with up to 99% yielding probability, which human experts can’t think of.

This great discovery will definitely speed up the process of chemical synthesis in recent future.

Details Description: Novel Machine Learning in Chemistry: Now Reaction Optimization is Easier than Ever!

Reference: B J. Shields, et. al., Nature, 590, 89–96 (2021) []

Real-time Design of the Catalytic Interface

In heterogeneous catalysis, the interface between metal catalyst and support plays a crucial role; thus after engineering a heterogenous catalyst perfectly before employing it for a reaction is important as the interface can’t be tuned further once it is inside the reaction vessel. But how will it be if the interface tunes up itself during the reaction process!!

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Ref. W. Yuan e. al., Science, 371, 517-521 (2021)

It’s unusual because an epitaxial rotation of the metal part is necessary over the rigid surface, which is pretty unexpected. However, W. Yuan et al. observed such an unexpected dependence of the atomic structure of Au-TiO2 interface during carbon monoxide (CO) oxidation.

By monitoring the gas and temperature and considering the advantage of the reversible and controllable rotation, they achieved in situ manipulation of the active Au-TiO2 interface. This amazing discovery is definitely opening a new direction towards the research on “real-time design of the catalytic interface”.

Reference: W. Yuan e. al., Science, 371, 517-521 (2021) [DOI: 10.1126/science.abe3558]

Endless Knot! A New Molecular Topology & One of The Best Chemistry Discoveries of Jan 2021

Natural molecular knots are common in DNA and proteins (only ~1% of protein data bank). Typically the molecular knots influence numerous properties of a molecule, that include elasticity, tensile strength, chirality, binding selectivity, and eventually the biological activity.

Artificially built molecular knots have also been reported; most of those were synthesized unexpectedly via twisting, folding, and threading of molecular building blocks. In fact, these are the classic methods to develop synthetic molecular knots.

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Structure of 74 knot coordination complex [Ref. D. A. Leigh et. al., Nat. Chem., 13, 117–122 (2021)]

The beauty of the recent discovery by D. A. Leigh and his group is the simplicity and practical utility of the procedure. Instead of implementing the above-mentioned half-chance methods, they incorporated a novel metal ions coordination-driven two-dimensional weaving strategy to derive molecular endless knots.

According to this study, Zn(II) or Fe(II) ions can act the major role to weave the ligand strands to form a woven 3 × 3 molecular grid, while tetrafluoroborate anions assist in templating the assembly of the interwoven grid.

The intra-grid closure of the strand ends of the resulting 3×3 interwoven grid via alkene metathesis finally generates a 74 knot topology corresponds to that of an endless knot. Undoubtfully, this discovery opens up a new direction towards the coordination-driven assembly of polymer chains.

Reference: D. A. Leigh et. al., Nature Chemistry, 13, 117–122 (2021) []

Carboformylation: One of the Best Chemistry Discoveries of the Month

Hydroformylation is a very important reaction in industry and academia where the installation of a C–H bond as well as an aldehyde group occurs across an unsaturated substrate. On the other hand, carboformylation reactions generate new C–C bonds along with the installation of the aldehyde group to increase molecular complexity. Notably, structurally diverse aldehydes having molecular complexity are in high demand to the organic chemists for constructing chemo-divergent molecular core.

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Schematic diagram of Pd-catalyzed Carboformylation reaction

Recently, Bill Morandi and co-workers reported a palladium-catalyzed four-component strategy to perform stereoselective carboformylation of alkynes utilizing an exogenous CO source, whereas a sterically congested hydrosilane and aroyl chlorides (as a carbon electrophile) were used as other components.

Why this discovery is so important?

Due to the easy oxidizing property of aldehydes, synthesize structurally complex aldehydes is not an easy task. On the other hand, aldehydes having molecular complexity are in high demand in synthetic organic chemistry, mainly to use as precursors for deriving complex molecules. Although hydroformylation is well-known, carboformylation, wherein a new C–C bond forms instead of a C–H bond, is not so established so far.

This discovery uncovered the inherent nature of a four-component reaction where carboformylation process occurs in-situ to fulfill high demanding complexity in Aldehydes.

Reference: Y. Ho Lee, et. al., Nature Chemistry,13, 123–130 (2021)

Mechanochemical Bond Scission: A Novel Tool for Drug Delivery

Thousand of bioactive molecules are being discovered every day but how many among those are converting to life-saving medicines?

Literally, the count is less than 0.01%.

The top reason behind the failures is poor drug selectivity that causes unwanted side effects and drug resistance. Developing a prodrug system, i.e., selective drug activation in response to stimuli via spatial and temporal control are the most promising strategies to overcome these issues.

Andreas Herrmann and co-workers uncovered the potentiality of ultrasound to activate prodrug systems through controlled scission of mechanochemically labile covalent bonds and weak non-covalent bonds. They introduced a polymer having a disulfide motif at the center.

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The way ultrasound works to release the drugs [Ref. S. Huo, et. al., Nat. Chem.,13, 131–139 (2021)]

The process worked in 3 steps:

  1. The polymer with disulfide motif released an alkaloid-based anticancer drug.
  2. The aminoglycoside antibiotics were activated by the mechanochemical opening and scission of the nucleic acid backbone.
  3. Activation of peptide antibiotic vancomycin and its complementary peptide target via force-induced scission of hydrogen bonds.

This is definitely a great discovery in the field of drug delivery.

Reference: S. Huo, et. al., Nature Chemistry,13, 131–139 (2021)

Hypoxia-Triggered Self-Assembly of Iron Oxide Nanoparticles to Amplifies MRI Signal of a Tumor 

Hypoxia (oxygen deficiency) is a very common feature among most solid tumors, which is an influencer for cancer treatment (e.g., chemo- and radiotherapy). However, with the traditional contrast agents, it is a challenging task to detect the distribution and extent of hypoxia in vivo.

Recently, Chunying Chen and his group established a novel hypoxia imaging probe by combining a hypoxia-triggered self-assembling iron oxide (UIO) nanoparticle and assembly-responding fluorescence dyes (NBD).

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Hypoxia-Triggered Self-Assembly to Amplifies MRI Signal

Nitroimidazole derivatives (the hypoxia-sensitive moiety) construct the cross-linking of UIO nanoparticles under hypoxia that form larger nanoparticle assemblies. This self-assembly

  1. Amplifies its T2-weighted MRI signal
  2. Increase the fluorescence intensity in hypoxia

This novel fluorescence probe is a potential discovery for improving hypoxia-targeted drug delivery.

Reference: H. Zhou, et. al., J. Am. Chem. Soc., 4, 1846–1853 (2021) []

Superatom! New Periodic Table?

Conventional atoms and superatoms, both follow similar Aufbau principles but chemically modified superatoms are unique compared to the former candidate. They have additional control on several parameters that includes surface modification, compositions, atomic packing, and size. This happens because the cluster (superatom) occupies a new set of orbitals that are defined by the entire group of atoms.

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Ref. J. Am. Chem. Soc., 4, 1683–1698 (2021)

Shinjiro Takano and Tatsuya Tsukuda designed an icosahedral Au13/Ag13 superatoms with the closed electron configuration that opens up a new direction towards the world of quasi-molecules as well as to construct a new periodic table of chemically modified superatoms.

In support of their design, they established the guiding principles of the electronic structures and also proposed the guidelines for hydride-mediated transformations targeted synthesis of the superatom.

Reference: S. Takano and T. Tsukuda, J. Am. Chem. Soc., 4, 1683–1698 (2021) []

Many other top-class chemistry research has been conducted in the past months and reported in several journals. It’s never been an easy job to pick up the best chemistry discoveries among them; however, based on practical utility and human welfare we listed the above discoveries as the winners.

In the Next Issue, we’ll uncover the best chemistry discoveries of the month Feb-Mar 2021.

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