Over the last half century, the remarkable advance in the field of asymmetric catalysis has drastically innovated the procedures of chemical synthesis of enantiomerically pure compounds. 1-3 However, the vast majority of these transformations are centred on thermochemistry wherein the product chirality is generally established at the ground state. Stereochemical control of photochemical reactions remains a formidable challenge owning to the intrinsic high reactivity of the excited state, for which the small molecules catalysts do not provide a general solution. 4-6 Here we show that this challenge can be tackled by genetically encoded, chemically evolved triplet photoenzymes embedded with a proficient synthetic photosensitizer. Structural optimization through four founds of rational mutagenesis afforded a proficient enzyme. It promoted enantioselective intramolecular [2+2] photocycloaddition of indole derivatives with marked substrate generality and excellent enantioselectivites (up to 99% enantiomeric excess). X-ray crystal structure of photoenzyme-substrate complex elucidated the important multiple noncovalent interactions that work synergistically to induce high enantioselectivity. This study shows that by merging the empowering mechanism of triplet energy transfer catalysis 7-10 with the delicate supramolecular cavity of proteins, the triplet

Reported here is the first catalytic atroposelective electrophilic amination of indoles, which delivers functionalized atropochiral N-sulfonyl-3-arylaminoindoles with excellent optical purity. This reaction was furnished by 1,6-nucleophilic addition to p-quinone diimines. Control experiments suggest an ionic mechanism that differs from the radical addition pathway commonly proposed for 1,6-addition to quinones. The origin of 1,6-addition selectivity was investigated through computational studies. Preliminary studies show that the obtained 3-aminoindoles atropisomers exhibit anticancer activities. This method is valuable with respect to enlarging the toolbox for atropochiral amine derivatives.

Two cobalt oxyfluoride antiferromagnets CoMOF5(pyz)­(H2O)2 (M = Nb 1, Ta 2; pyz = pyrazine) have been synthesized via conventional hydrothermal methods and characterized by thermogravimetric (TGA) analysis, FTIR spectroscopy, electron spin resonance (ESR), magnetic susceptibility, and magnetization measurements at both static low field and pulsed high field. The single-crystal X-ray diffraction indicates both compounds 1 and 2 are isostructural and crystallize in the monoclinic space group C2/m with a two-dimensional Co2+ triangular lattice in the ab plane, separated by the nonmagnetic MOF5 (M = Nb 1, Ta 2) octahedra along the c-axis with large intertriangular-lattice Co···Co distance. Because of low dimensionality together with frustrated triangular lattice, compounds 1 and 2 exhibit no long-range antiferromagnetic order until ∼3.7 K. Moreover, a spin flop transition is observed in the magnetization curves at 2 K for both compounds, which is further confirmed by ESR spectra. In addition, the ESR spectra suggest the presence of a zero-field spin gap in both compounds. The high field magnetization measured at 2 K saturates at ∼7 T with M s = 1.55 μB for 1 and 1.71 μB for 2, respectively, after subtracting the Van Vleck paramagnetic contribution, which is usually observed for Co2+ ions with pseudospin spin of 1/2 at low temperature. Powder-averaged magnetic anisotropy of g = 3.10 for 1 (3.42 for 2) and magnetic superexchange interaction J/k B = −3.2 K for 1 (−3.6 K for 2) are obtained.

The nonheme diiron toluene/o-xylene monooxygenase (ToMO) is the most studied toluene monooxygenase that mediates an aromatic hydroxylation reaction. In this work, QM/MM calculations were performed to understand the reaction mechanism. It is revealed that the μ-η 2 :η 2 peroxodiferric species is the reactive intermediate after the binding of the O 2 molecule to the reduced diferrous center. Subsequently, both a stepwise and a concerted mechanism involving the critical OÀ O bond cleavage and CÀ O bond formation were considered. The latter was calculated to be more favorable, suggesting that the formation of a highvalent diferryl Q intermediate is not needed. The isomeric formation of the phenol product was found very facile. The first step was calculated to be rate-limiting, with a barrier of 17.6 kcal/mol for the ortho-hydroxylation.