The 2‐Arsaethynolate Anion: Synthesis and Reactivity Towards Heteroallenes

Abstract

The synthesis and isolation of the 2‐arsaethynolate anion, AsCO−, and its subsequent reactivity towards heteroallenes is reported. Reactions with ketenes and carbodiimides afford four‐membered anionic heterocycles in formal [2+2] cycloaddition reactions. By contrast, reaction with an isocyanate yielded a 1,4,2‐diazaarsolidine‐3,5‐dionide anion and the unprecedented cluster anions As102− and As124−. These preliminary reactivity studies hint at the enormous potential synthetic utility of this novel anion, which may be employed as an arsenide (As−) source.

Photoelectron Spectroscopy and Theoretical Study on Monosolvated Cyanate Analogue Clusters ECX–·Sol (ECX– = NCSe–, AsCSe–, and AsCS–; Sol = H2O, CH3CN)

“…Cyanate (NCO – ) and thiocyanate (NCS – ) are textbook pseudohalides, and their molecular properties have been well characterized. − Their analogues containing heavier pnictogen E (P, As) and chalcogen X (S, Se) species, however, had remained elusive. Recent successes in synthesizing these long-sought heavier ECX – species − opened the way for exploring their chemistry as a viable precursor for synthesis of novel P-, ,− As-, ,, and Se-containing compounds. Of particular interest is their behavior as ambidentate ligands that can form both E- or X-coordination species. − This is different from their lighter analogues (NCO – , NCS – ) that are only bound to metals (Th, U, Re, and W) via the N-terminal. , For example, PCO – prefers O-coordination for Th and U and P-coordination for W and Re, , while PCS – could bind W via both P- and S-coordination .…”

“…1−4 Their analogues containing heavier pnictogen E (P, As) and chalcogen X (S, Se) species, however, had remained elusive. Recent successes in synthesizing these longsought heavier ECX − species 5−8 opened the way for exploring their chemistry as a viable precursor for synthesis of novel P-, 6,9−13 As-, 7,12,14 and Se-containing compounds. Of particular interest is their behavior as ambidentate ligands that can form both E-or X-coordination species.…”

Photoelectron Spectroscopy and Theoretical Studies of PCSe−, AsCS−, AsCSe−, and NCSe−: Insights into the Electronic Structures of the Whole Family of ECX− Anions (E=N, P, As; X=O, S, Se)

“…[4][5][6][7][8][9][10][11] More recently, synthetic methods allowing for the isolation of bulk quantities of heavier ECX -(E = P, As; X = O, S, Se) species have become available, enabling comparative studies of the bonding and reactivity profiles of this interesting library of anions. For example, AsCO − was isolated by Goicoechea in 2016, [12] and found to play important role in the formation of arseniccontaining compounds. [12][13][14] The long-sought, PCSe − , AsCS − , and AsCSe − ions were also synthesized and characterized by Goicoechea's group in 2018.…”

“…For example, AsCO − was isolated by Goicoechea in 2016, [12] and found to play important role in the formation of arseniccontaining compounds. [12][13][14] The long-sought, PCSe − , AsCS − , and AsCSe − ions were also synthesized and characterized by Goicoechea's group in 2018. [10] Triatomic pseudohalide anions ECX − are extensively employed in coordination chemistry and organic synthesis.…”

“…[15][16][17][18] Electron delocalization over the three atoms gives rise to three predominant resonance structures (E≡C−X − , − E=C=X, and 2− E−C≡X + ). [4,12,19] Previous studies have shown that the relative weights of these resonances vary with the nature of E and X, [4,10,12,13,19] and that, consequently, the ions differ in their behavior and in their reactivity towards Lewis acids. For example, the cyanate (NCO -) and thiocyanate anions (NCS -) are dominated by the E≡C−Xresonance structure.…”