Functional Polythioamides Derived from Thiocarbonyl Fluoride.

Polythioamide is a unique type of sulfur-containing polymer with advanced functionalities. Nonetheless, the elemental sulfur commonly used in their synthesis tends to react readily with unsaturated functional groups, thereby limiting the scope of eligible substrates. Inspired by the highly efficient sulfur-fluoride exchange (SuFEx) polymerization through discrete hubs, we present herein a pioneering and versatile approach to the synthesis of polythioamides from diboronic acids, secondary diamines, and thiocarbonyl fluoride as the central connective hub.

General Access to N-CF Secondary Amines and Their Transformation to N-CF Sulfonamides.

The synthesis of N-CF compounds through fluorination or trifluoromethylation of N-containing compounds has been extensively investigated. However, general access to N-CF compounds simply from N-CF secondary amines is hampered by the challenging preparation and instability of these amines, as well as a much lower reactivity due to the strong electron-withdrawing nature and steric bulk of the trifluoromethyl moiety. Herein, we report a general and highly efficient synthesis of N-CF secondary amines with excellent isolated yields via the addition of the in situ generated difluoromethyl imine (R-N=CF ) intermediates with hydrogen fluoride, which is mildly produced by triethylsilane and silver fluoride.

An Analytical Model for the Distributions of Velocity and Discharge in Compound Channels with Submerged Vegetation.

Based on the momentum transfer theory, an analytical model is proposed for the velocity and discharge distributions in compound channels with submerged vegetation on the floodplain. The partially vegetated channel was divided into three sub-regions, i.e.