Chemistry Paper 6

[Zee Palmer]

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In this issue we feature several articles that explore advances in the study of phase separation. They highlight some recently reported mechanistic features and progress in the methodology used to study it within cells, and they delve into the implications that phase separation has for select cellular functions.

Liquid droplets form in cells to concentrate specific biomolecules (while excluding others) in order to perform specific functions. The molecular mechanisms that determine whether different macromolecules undergo co-partitioning or exclusion has so far remained elusive. Now, two studies uncover key principles underlying this selectivity.

The 2023 Nobel Prize in Chemistry has been awarded to Moungi G. Bawendi, Louis E. Brus and Alexei I. Ekimov for the discovery and synthesis of quantum dots. In recognition of this award, Nature Portfolio presents a collection of research, review and opinion articles that highlight the development of quantum dots over the past three decades.

The combination of techniques such as machine learning, artificial intelligence, robotics and automation can be used to accelerate chemical and materials synthesis. This Focus issue showcases developments in the automation and digitalization of synthesis, as well as highlights the challenges to be overcome in this area.

Nature Chemical Engineering is open for submissions. The journal will cover a broad range of systems and scales that significantly advance fundamental research, aid product and process development and explore new technological solutions, all in the context of core chemical engineering approaches. It will publish research, reviews and opinion articles.

Singlet fission produces two molecular excitations from one photon and has the potential to boost solar cell efficiencies. Now it has been shown that magnetic fields can reveal the spectral signatures of the multi-excitonic intermediates in this process.

Molecular geometry can influence chemical reactivity through several opposing effects. By selecting individual conformers of hydroquinone in the chemi-ionization reaction with metastable neon, it is now shown that reaction pathways can be governed by molecular alignment due to geometry-dependent forces that are, however, countered by molecular rotation.

Lysine ubiquitination, catalysed by E3 ubiquitin ligases, is pivotal for regulating protein stability and cell signalling. Using protein semisynthesis, the roles of the C-terminal carboxylate and conformational interconversion in HECT-domain E3 catalysis are now characterized, revealing evolutionary plasticity in side chain versus backbone utilization.

Although natural terpenoid cyclases generate polycyclic structures through cationic intermediates, alternative radical cyclization pathways are underexplored. Now an artificial radical cyclase has been prepared by anchoring a biotinylated cobalt Schiff-base complex within a chimeric streptavidin scaffold. Chemogenetic optimization of the catalytic performance affords enantioenriched terpenoids via a metal-catalysed H-atom transfer mechanism.

Hydrogenation catalysis is commonly associated with (noble) transition metals that undergo oxidative addition of H2 and subsequently transfer hydrogen atoms to unsaturated substrates. Now, a geometrically constrained phosphenium cation can facilitate both of these challenging transformations.

Hydroxyl radicals (OH) are important reactive oxygen species in environmental chemistry. The most efficient way to generate them is through a single-electron water-oxidation step, but this light-driven process is inefficient over inorganic semiconductor materials. Now, a judiciously designed polymeric carbon nitride has demonstrated high photocatalytic efficiency.

In molecular biology, few molecules have had as profound an impact as Cas9. Madeleine King, Kayla Perry, Mitchell McAndrew and Audrone Lapinaite discuss how this multifunctional molecular tool of genetic engineering is revolutionizing multiple fields.

Environmental contamination is in the news more than ever. Shira Joudan introduces key concepts to talk about what happens to chemicals in the environment and what chemists should consider in their day-to-day lives, both at work and at home.

Create your free account to receive personalised content alerts and Re:action, our weekly newsletter of the top chemical science stories handpicked from a range of magazines, journals and websites alongside insight and analysis from our expert editorial team.

Performance-enhancing chemicals address the process chemistry side of manufacturing, ensuring that each stage runs smoothly. Defoamers and dispersants tackle practical issues such as foaming and clumping in the pulping vats, while cleaning and descaling treatments ensure water quality meets the required standards.

Biocides are therefore another crucial class of additive. Oxidising treatments such as hydrogen peroxide or halogenated hydantoin damage microbial cell structure, disrupting the flow of nutrients across the cell wall. Although highly effective, these redox active reagents are extremely sensitive to the operating conditions and often require additional additives such as corrosion inhibitors and stabilisers. Non-oxidising biocides like glutaraldehyde and quaternary ammonium salts are much less reactive and instead interfere with important microbial processes such as respiration and reproduction. These slower-acting treatments are stable and easier to handle so most mills use a combination of oxidative and non-oxidative strategies.

Determining the correct quantities and combinations of additives is a complex matter. Each grade of paper undergoes its own separate optimisation process and the precise recipes used by each mill are kept closely guarded secrets.

The Institute for Paper Chemistry was graduate institute for training paper chemists, organized by Lawrence but financed by the paper industry. The Institute had its own Board of Trustees and operated its own budget. Lawrence awarded Master of Science and Doctor of Philosophy degrees to graduates of the Institute. The Institute transferred its operations from Appleton to Atlanta, Georgia in 1989, where it currently exists as the Renewable Bioproducts Institute at Georgia Tech.

Samuel Plantz, then president of Lawrence University, recommended the creation of a committee within the Board of Trustees to consider adding classes to the curriculum in paper chemistry to be paid for by the paper mills in the area based on a similar program at the University of Maine.

Thanks to the work of Henry Wriston, president of Lawrence 1925-1937, the Institute of Paper Chemistry was founded as a partnership between Lawrence College (now Lawrence University) and the paper industry to promote research and innovation in the industry- one which was heavily centered in Appleton. The Lawrentian summarized the goals of the institute from a letter sent to President Herbert Hoover by Wriston:

Dr. Wriston pointed out that the purposes of the Institute are threefold : first, to develop technically trained chemists who will be available for the particular needs of the paper industry; second, to establish a comprehensive library and information service for the advantage of the paper industry; and finally, to promote and carry forward research both for individual corporations and for the group as a whole.

Classes began in the winter of 1929 and the first ten graduates earned their Master's Degrees at Lawrence's commencement ceremony in the spring of 1931. For the first year of operation the IPC had no building, and instead operated out of rented space in Alexander Gym. A building was constructed across the street from the gym and dedicated in the fall of 1931 and a library constructed a year later.

World War II impacted the Institute as it did every industry and school. As paper resources became scarce the IPC engaged in many projects to support the war effort. The most unique of these projects was the design for a house to be constructed of reclaimed waste paper and intended to temporarily house refugees. A house was constructed on campus using the design and stood there until it was dismantled in 1952.

In the years after the war the Institute grew rapidly, with the renovation of the original two buildings and construction of three additional academic buildings and eight small apartment buildings to the west of the campus in order to house students and their families.

Thanks to a $1,000,000 donation, the largest in the Institute's history, a program was created and new building constructed to put more of a focus on doctoral research and encouraging students to pursue a PhD, with the goal of increasing the student body by a third.

Stemming from a grant from the Environmental Protection Agency, a large focus was place on researching the environmental impacts of the paper production process including the presence of mercury and PCBs in wastewater from production plants.

Across the United States, a focus on energy was shifting the research focus to reducing energy consumption in industrial settings. Research at the IPC focused on reducing energy consumption throughout paper production plants.

In order to continue to grow and adapt to the changing field of pulp and paper, the IPC decided to partner with Georgia Institute of Technology and relocate to Atlanta, Georgia. The move also saw a name change to Institute of Paper Science and Technology. It is now named the Renewable Bioproducts Institute.

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