acetate quickened the process. The metal ions didn’t just increase the rate of drying, they also integrated into the gel’s molecular architecture. The researchers say the technological advance revolutionized the ability of artists “to express sensations or feelings, capturing momentary effects of light” using more fluid, spontaneous, and loose brushwork.—SARAH EVERTS
BIOLOGICS
CREDIT: ANDREI LOMIZE/WIKIMEDIA COMMONS (RIBBON STRUCTURE)
▸ Predicting immune response to protein Tiny changes to a therapeutic protein can enhance its performance or initiate a dangerous immune reaction. Novo Nordisk knows that all too well after dropping a Phase III drug trial in 2012 for its engineered Factor VII blood-clotting protein designed to treat hemophilia. Using publicly available software, Novo Nordisk and Food & Drug Administration researchers began outlining methods to predict how immune cells chop up and display engineered proteins on their surface. Their model has shown that two out of three engineered changes in the Factor VII protein activate unwanted T cell immune responses in some people (Sci. Transl. Med. 2017, DOI: 10.1126/ scitranslmed. aag1286). One Factor VII protein determining factor for the response is a person’s unique HLA genes, which are involved in presenting foreign protein fragments to T cells. The researchers subsequently used the model with HLA testing to correctly identify patients from the failed clinical trial that did and didn’t develop antibodies to the engineered protein. HLA testing is already common for organ donations, prompting study leader Zuben E. Sauna of FDA to say that more studies like this may lead to HLA tests being applied in “precision medicine,” where drugs can be given to the majority of pa-
INORGANIC CHEMISTRY
Chromium complex has a long luminescent glow Ruthenium bipyridine and related precious-metal complexes are popular because they exhibit long-lived, redox-active excited states that are useful for making solar cells and light-emitting devices and as sensitizers for photocatalytic organic reactions. Researchers would like to replace the precious metals with more abundant first-row transition metals, such as iron, but they have been waylaid so far because the excited-state luminescence lifetimes are too short. A key to modulating the properties of the complexes to extend the lifetime is designing ligands that better stabilize the metal ions. To that end, Laura A. Büldt, N Oliver S. Wenger, and their coworkers at the University of Basel have designed a N N bulky chelating diisocyanide terphenyl Cr ligand that dramatically improves chromiN um(0)’s excited-state lifetime, surpassing N that of the best iron(II) complexes by N two orders of magnitude (J. Am. Chem. Soc. 2017, DOI: 10.1021/jacs.6b11803). The researchers say the electronic effects of their ligand and the cage structure it forms around the chromium(0) ion provides a room-temperature excited-state lifetime of 2.2 nanoseconds, which exceeds the 37 picoseconds of the previous iron(II) Tris(diisocyanide)chromium(0) complex record holder. In addition, they found that the chromium complex is a stronger photoreductant than ruthenium tris(bipyridine). Wenger’s group has tested the chromium complex and an analogous molybdenum complex in photoredox catalysis and is exploring grafting the chromium complex onto semiconductor surfaces to make dye-sensitized solar cells.—STEVE RITTER
tients they will help, and withheld from the few that they could harm.—RYAN CROSS
CATALYSIS
▸ Boron nitride catalyzes olefin hydrogenations For the second time in about a month, researchers report that boron nitride, which ranks as a well-known catalyst support, but not as a catalyst, catalyzes industrially important reactions. This time it’s olefin hydrogenation, a reaction used for making fuels and chemicals and for processing foods (ACS Omega 2016, DOI: 10.1021/ acsomega.6b00315). The advance may lead to lower-cost, metal-free industrial hydro-
genation catalysts. A few studies in recent years have reported that boron nitride, especially the hexagonal form, h-BN, can catalyze water-splitting and other processes. Last month, scientists upped BN’s catalysis status by showing that it can drive industrially important dehydrogenation reactions. Now, a team led by Richard G. Blair of the University of Central Florida has shown that defect-laden h-BN, made via a ball-milling process, can serve as an active catalyst for hydrogenating propene, cyclohexene, diphenylethylenes, and other alkenes. The team found that h-BN mediates hydrogenations under milder conditions than those used with nickel-based hydrogenation catalysts and is more active than metal-free frustrated Lewis pair catalysts. NMR analysis and binding-energy calculations show that nitrogen vacancies are most likely the catalytically active sites among the eight types of lattice defects examined.—MITCH JACOBY JANUARY 16, 2017 | CEN.ACS.ORG | C&EN
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