A series of Mn(II), Fe(II), and Co(II) bisaryloxide dimers ([M(OC₆H₂-2,4,6-Cy₃)₂]₂ {M = Mn (1), Fe (2), and Co (3)} were synthesized by the addition of 2,4,6-tricyclohexylphenol (HOC₆H₂-2,4,6-Cy₃) to the silyl amido dimers [M(N(SiMe₃)₂)₂]₂ (M = Mn, Fe, Co; Cy = cyclohexyl). An unexpected and unique Co(II) phenoxide derivative (4), [Co(OC₆H₂-2,4,6-Cy₃)(O₂C₆H-3,5,6-Cy₃)]₂, was obtained via ligand rearrangement of 3 at ca. 180 °C. This yielded 4 in which there are two unchanged, bridging phenoxide ligands as well as a terminal bidentate semiquinone ligand bound to each cobalt. Complexes 1 and 2 did not undergo such a rearrangement under the same conditions; both are thermally stable to temperatures exceeding 250 °C and feature numerous short-contact (<2.5 Å) H···H interactions consistent with the presence of dispersion stabilization. Use of the aryloxide ligand -OC₆H₃-2,6-Prⁱ₂ (Prⁱ = isopropyl), which is sterically similar to -OC₆H₂-2,4,6-Cy₃ but produces fewer close H···H interactions, gave the trimeric species [M(OC₆H₃-2,6-Prⁱ₂)₂]₃ {M = Fe (5) or Co (6)} which feature a linear array of three metal atoms bridged by aryloxides. The higher association number in 5 and 6 in comparison to that of 1-3 is due to the lower dispersion energy donor properties of the -OC₆H₃-2,6-Prⁱ₂ ligand and the lower stabilization it produces.

Carbene polymerization provides polyolefins that cannot be readily prepared from olefin monomers; however, controlled and living carbene polymerization has been a long-standing challenge. Here we report a new class of initiators, (π-allyl)palladium carboxylate dimers, which polymerize ethyl diazoacetate, a carbene precursor in a controlled and quasi-living manner, with nearly quantitative yields, degrees of polymerization >100, molecular weight dispersities 1.2-1.4, and well-defined, diversifiable chain ends. This method also provides block copolycarbenes that undergo microphase segregation. Experimental and theoretical mechanistic analysis supports a new dinuclear mechanism for this process.

This paper documents the design and application of ATLAS (Automobile and Technology Lifecycle-Based ASsignment), a comprehensive household vehicle transaction and technology adoption micro-simulator in the San Francisco Bay Area. ATLAS evolves the fleet mix of individual households by simulating the vehicle transaction and choice decisions in response to co-evolving demographics, land use, and vehicle technology simulations. While most existing literature has focused on the aggregate clean vehicle uptake, this paper differentiates distributional effects and decomposes the underlying mechanisms across heterogeneous sub-populations of households. Using scenarios and sensitivity simulations that vary vehicle technology and policy assumptions, we find that Zero Emission Vehicles (ZEVs) penetrate into higher income groups at a faster rate than into lower income groups, which is intuitive and aligns with expectations. Interestingly, the relative income disparity in ZEV ownership shrinks over time across all scenarios, with a ZEV mandate coupled with declining battery cost leading to the greatest reduction in disparity of ZEV ownership by 2050. Federal, state, and local financial incentives influence the redistribution of ZEV uptake across income groups and contribute to narrowing income disparity. Vehicle transaction frequency and new versus used market dynamics are found to be important factors contributing to the income disparity.

The cross section of top quark-antiquark pair production in proton-proton collisions at [Formula: see text] is measured by the CMS experiment at the LHC, using data corresponding to an integrated luminosity of 2.2[Formula: see text]. The measurement is performed by analyzing events in which the final state includes one electron, one muon, and two or more jets, at least one of which is identified as originating from hadronization of a b quark. The measured cross section is [Formula: see text], in agreement with the expectation from the standard model.