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Phosphaphenalenes, extended π conjugates with the incorporation of phosphorus, are attractive avenues towards molecular materials for the applications in organic electronics, but their electron accepting ability have not been investigated. Herein we present systematic studies on the reductive behavior of a representative phosphaphenalene and its oxide by chemical and electrochemical methods. The chemical reduction of the phosphaphenalene by alkali metals reveals the facile P−C bond cleavage to form phosphaphenalenide anion, which functions as a transfer block for structure modification on the phosphorus atom. In contrast, the pentavalent P‐oxide reacts with one or two equivalents of elemental sodium to form stable radical anion and dianion salts, respectively. [ABSTRACT FROM AUTHOR]

Herein, we describe how computational mechanistic understanding has led directly to the discovery of new 2H‐phosphindole for C−CAr bond activation and dearomatization reaction. We uncover an unexpected intramolecular C−H bond activation with a 2H‐phosphindole derivative. This new intriguing experimental observation and further theoretical studies led to an extension of the reaction mechanism with 2H‐phosphindole. Through DFT calculations, we confirm that within a five‐membered ring, the polarizable PC3 unit orchestrates the formation of an electrophilic phosphorus atom (P+) and a nucleophilic carbon atom (C−). This kinetically accessible ambiphilic phosphorus/carbon couple is spatially separated by geometric constraints, and their reactivity is modulated through structural resonance. [ABSTRACT FROM AUTHOR]

tert‐Butylthiophosphinidene complex [tBuSP‐W(CO)5] was generated by dissociation of 1‐(tert‐butylthio)phosphirane–W(CO)5 complex under mild conditions. The formation of transient [tBuSP‐W(CO)5] was indicated by trapping reactions with 2,3‐dimethyl‐1,3‐butadiene, alkynes, phenanthrene‐9,10‐dione, and methanol. The LUMO of [MeSP‐W(CO)5] is significantly lower in energy than those of [Me2NP‐W(CO)5], [MeOP‐W(CO)5], and [Me2PP‐W(CO)5]. The HOMO of [MeSP‐W(CO)5] contains a significant contribution from the in‐plane lone pair of P and the LUMO shows a typical π* characteristic. Since stabilized by sulfur lone pair and coordinated by W(CO)5, [tBuSP‐W(CO)5] undergoes facile and reversible cycloadditions with alkenes and alkynes. [ABSTRACT FROM AUTHOR]