The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adma.202107900.A data mining approach to discover and develop new organic nonlinear optical crystals that produce intense pulses of terahertz radiation is demonstrated. The Cambridge Structural Database is mined for noncentrosymmetric materials and these structural data are used in tandem with density functional theory calculations to predict new materials that efficiently generate terahertz radiation. This enables us to (in a relatively short time) discover, synthesize, and grow large, high-quality crystals of four promising materials and characterize them for intense terahertz generation. In a direct comparison to the current state-of-the-art organic terahertz generation crystals, these new materials excel. The discovery and characterization of these novel terahertz generators validate the approach of combining data mining with density functional theory calculations to predict properties of high-performance organic materials, potentially for a host of exciting applications.
We report the synthesis of a 2-phosphinoimidazole-derived bimetallic
Rh(II) complex that enables intramolecular allene hydroamination to
form 7- to 10-member rings in high yield. Monometallic Rh complexes,
in contrast, fail to achieve any product formation. We demonstrate
a broad substrate scope for formation of various N-heterocycles. Macrocyclizations that form 11- to 15-member N-heterocycles are also demonstrated. Mechanistic studies
suggest that the reaction proceeds via reversible allene insertion
with a Rh-hydride followed by C–N bond-forming reductive elimination.
We hypothesize that the reactivity observed with our catalyst vs monometallic
Rh complexes is derived from the bimetallic nature of our complex.
We report the synthesis of a bimetallic Rh(I) complex containing a bridging CO ligand that facilitates Rh–Rh bond formation. This bimetallic complex enables intramolecular allene hydroamination to form seven to ten-member rings in high yield. Monometallic Rh complexes, in contrast, fail to achieve any product formation. We demonstrate a broad substrate scope for formation of a variety of N-heterocycles in good to excellent yields. Macrocyclization reactions that form eleven to fifteen-membered heterocycles are also demonstrated. Mechanistic studies show that the reaction likely proceeds via catalyst protonation by trifluoroacetic acid, followed by reversible allene insertion and C–N bond-forming reductive elimination. The difference in product selectivity observed with our bimetallic catalyst vs monometallic Rh complexes may result from cooperativity between the two metals.
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