Dickey Chen (trunksummer36)

In 1864, Hugo Schiff, aged 30, discovered the reaction of aromatic aldehydes with primary amines to give imine derivatives. A C═N imine bond presents the unique properties of being strong, as expected for a covalent double bond, and of being reversible due to a fast hydrolytic process. In view of such features, Schiff base condensations are thermodynamically controlled, which, in the case of reactions involving multifunctional aldehydes and primary amines, allow the formation of complex and sophisticated structures through a trial-and-error mechanism. Back hydrolysis can be prevented by hydrogenating C═N bonds under mild conditions. In such a way, stable rings and cages of varying sizes can be synthesized. Moreover, transition and post-transition metal ions, establishing coordinative interactions with imine nitrogen atoms, can address Schiff base condensations of even more complex molecular systems, whose structure is controlled by the geometrical preferences of the metal. Metal template Schiff base condensations have produced multinuclear metal complexes exhibiting the shape of tetrahedral containers, of double helices, and, supreme wonder, of the Borromean rings. These molecular objects cannot be compared to the masterpieces of painting and sculpture of the macroscopic world, but they instill in the viewer aesthetical pleasure and admiration for their creators.This work describes a one-step synthesis of 1H-indole-2,3-dicarboxylates through C-H activation. Rhodium-catalyzed tandem C-H activation and annulation of 2-acetyl-1-phenylhydrazines with maleates proceeded smoothly in the presence of additive NaOAc and oxidant Ag2CO3 and produced the corresponding indole derivatives, 1H-indole-2,3-dicarboxylates, in satisfactory to good yields. A variety of useful functional groups were tolerated on the benzene ring including halogen atoms (F, Cl, Br, and I) and methoxycarbonyl groups.The development of practical porous materials for the selective capture of CO2 from flue gas and crude biogas is highly critical for both environment protection and energy safety. Here, a novel metal-organic framework (FJI-H29) has been prepared, which not only has excellent acid-base resistance but also possesses polar micropores (3.4-4.3 Å) that can match CO2 molecules well. FJI-H29 can selectively capture CO2 from N2 and CH4 with excellent separation efficiency and suitable adsorption enthalpy under ambient conditions. Breakthrough experiments further confirm its practicability for both CO2/N2 and CO2/CH4 separation. All of these confirm FJI-H29 is a practical CO2 adsorbent. Modeling calculations reveal that the confinement effect of micropores and the polar environment synergistically promotes the selective adsorption of CO2, which will provide a potential strategy for the synthesis of a practical metal-organic framework for CO2 capture.Two anthryl platinum(II) N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-benzenediamine Schiff base complexes were synthesized, with the anthryl attached via its 9 position (Pt-9An) or 2 position (Pt-2An) to the platinum (Pt) Schiff base backbone. The complexes show unusually small Stokes shifts (0.23 eV), representing a very small energy loss for the photoexcitation/intersystem crossing process, which is beneficial for applications as triplet photosensitizers. Phosphorescence of the Pt(II) coordination framework (ΦP = 11.0%) is quenched in the anthryl-containing complexes (ΦP = 4.0%) and shows a biexponential decay (τP = 3.4 μs/87% and 18.2 μs/13%) compared to the single-exponential decay of the native Pt(II) Schiff base complex (τP = 3.7 μs). Femtosecond/nanosecond transient absorption spectroscopy suggests an equilibrium between triplet anthracene (3An) and triplet metal-to-ligand charge-transfer (3MLCT) states, with the dark 3An state slightly lower in energy (1.96 eV for Pt-9An and 1.90 eV for Pt-2An) than the emissive 3MLCT state (1.97 eV for Pt-9An and 1.91 eV for Pt-2An). Intramolecular triplet-triplet energy tr