1,3,4-Azadiphospholides as building blocks for scorpionate and bidentate ligands in multinuclear complexes

Synthesis of 1,2,4-diazaphospholes via base-promoted cyclization reaction of hydrazonoyl chlorides and [Bu4N][P(SiCl3)2]

Aromatic 1,2,4-diazaphospholes featuring distinct hybrid-mode nitrogen atoms (N(λ3σ2), N(λ3σ3)) and low-valent phosphorus atoms (λ3σ2) exhibited the characteristic of serving as unique hybrid ligands. This study presented a one-pot reaction involving the base-promoted stepwise cyclization of hydrazonoyl chlorides and [Bu4N][P(SiCl3)2] to yield 1,2,4-diazaphospholes, providing an effective method for synthesizing such compounds.

Hydrazone Phosphaketene as a Synthetic Platform To Obtain Three Classes of 1,2,4-Diazaphosphol Derivatives by Switchable Chemoselectivity Strategies

We introduce switchable chemoselectivity strategies based on the hydrazone phosphaketene intermediate to synthesize three classes of 1,2,4-diazaphosphol derivatives. First, the five-membered heterocyclic P and O anion intermediates acted as nucleophilic agents in the selective construction of C-P and C-O bonds. Second, the phosphinidene served as a phosphorus synthon, allowing for the formation of C-P and C-N bonds. Finally, a stepwise mechanism, supported by DFT calculations, was invoked to explain the reaction selectivity.

Recent advances in the chemistry of the phosphaethynolate and arsaethynolate anions

Over the past decade, the reactivity of 2-phosphaethynolate (OCP^-), a heavier analogue of the cyanate anion, has been the subject of momentous interest in the field of modern organometallic chemistry. It is used as a precursor to novel phosphorus-containing heterocycles and as a ligand in decarbonylative processes, serving as a synthetic equivalent of a phosphinidene derivative. This perspective aims to describe advances in the reactivities of phosphaethynolate and arsaethynolate anions (OCE^-; E = P, As) with main-group element, transition metal, and f-block metal scaffolds. Further, the unique structures and bonding properties are discussed based on spectroscopic and theoretical studies.