Synthesis and X-ray Characterization of Alkali Metal 2-Acyl-1,1,3,3-tetracyanopropenides

Abstract

A novel route for synthesis of 2-acyl-1,1,3,3-tetracyanopropenides (ATCN) salts in high yields and excellent purities starting from readily available methyl ketones, malononitrile, bromine, and alkali metal acetates is reported. The starting aryl(heteroaryl) methyl ketones were oxidized to the corresponding α-ketoaldehydes by new a DMSO-NaBr-H2SO4 oxidation system in yields up to 90% within a short reaction time of 8-10 min. The subsequent stages of ATCN preparation are realized in aqueous media without use of any toxic solvents, in accordance with principle 5 of "green chemistry". Lithium, sodium, potassium, rubidium, and cesium 2-benzoyl-1,1,3,3-tetracyanopropenides were characterized by X-ray diffraction analysis. These salts show a good potential for synthesis of five- and six-membered heterocycles and may serve as potentially useful ligands in coordination and supramolecular chemistry.

Gadolinium (III) 2‐Benzoyl‐1,1,3,3‐tetracyanopropenide Diacetate: Synthesis and Crystal Structure

“…2‐Acyl‐1,1,3,3‐tetracyanopropenides (ATCN) are a new type of TCA salts, which contains the carbonyl group in addition to the TCA anion. Recently, we reported a fast and convenient synthesis of alkali metal ATCNs based on readily available reagents . The X‐ray diffraction analysis reveals that most of these salts have 1D or 2D layered crystal packing and TCA anions are included in the coordination environment of the metal cation in all cases (an example is shown in Figure ).…”

“…Coordination environment of K in potassium 2‐benzoyl‐1,1,3,3‐tetracyanopropenide with 50 % probability ellipsoids. Bond lengths /Å: K···O1 2.708, K···O2 2.765, K···O2 i 2.805; K···N1 ii 2.827, K···N3 iii 2.891, K···N4 i 2.808; · K···K i distance is 3.984 Å …”