Hydrophosphorylation of Imines: Synthetic Methodology for the Synthesis of Small Molecules and Materials.
Abstract
The purification of contaminated wastewater effluent is an increasingly important aspect of sustainable chemistry. Several types of materials have been generated that can aid in the purification or removal of contaminants from aqueous or organic systems. By exploiting the chemistry of primary phosphines in the hydrophosphorylation reaction, we generated novel bis-α-aminophosphine chalcogenides as nitrogen, phosphorus, and chalcogen (O, S) -rich molecules. This novel methodology was investigated in-depth through mechanistic studies that included kinetic isotope effect (KIE), Hammett analysis, and trapping experiments. The functional group tolerance of the reaction was also investigated, and subsequently resulted in the formation of a small family of bis-α-aminophosphine chalcogenides, which were comprehensively characterized including the solid-state structure. Applying the reaction methodology to diimine containing compounds results in the formation of linear poly(α-aminophosphine) chalcogenides as heteroatom-rich polymers. Comprehensive characterization was conducted using various spectroscopic and thermal methods. The depolymerization of the afforded poly(α-aminophosphine) chalcogenides was investigated using reducing conditions and gratifyingly the quantitative depolymerization was observed. Addition of a cross-linker in the form of a tri-imine resulted in the formation of poly(α-aminophosphine) chalcogenide networks that showed swelling characteristics. The networks were probed in UO22+ sequestration studies and ultimately displayed promising uptake of UO22+ cations.