Formation and Reactivity of a C‐P‐N‐Sc Four‐Membered Ring: H₂, O₂, CO, Phenylsilane, and Pinacolborane Activation

Abstract

Reaction of scandium dimethyl complex LScMe (L=[2-{N(DIPP)C(Ph)N}C H CH=N(DIPP)] , DIPP=2,6-(iPr) C H ) (2) with bulky phosphine ArPH (Ar=2,6-{3,5-(Me) C H } C H ) gives an unprecedented scandium 2,3-azaphosphametallacyclobutane complex L'Sc (L'=[2-{N(DIPP)C(Ph)N}C H C(H)P(2,6-{3,5-(CH ) C H } C H )N(DIPP)] ) (3) that contains a C-P-N-Sc four-membered ring. Complex 3 was characterized by X-ray crystallography, revealing a short distance between the Sc and P atoms (2.786(1) Å), but without a direct Sc-P bonding interaction. The formation of 3 involves a complete cleavage of the imino bond of the tridentate ligand L and C-P and N-P bond coupling. Complex 3 not only activates H under mild conditions to give a H-H bond cleavage product, but also reacts with O , CO, phenylsilane, and pinacolborane to produce novel products through cleavage and formation of various bonds.

An Alkali-Metal Halide-Bridged Actinide Phosphinidiide Complex

“…Metal-element (ME) multiple-bonded compounds, including terminal phosphinidene complexes (MP), have been an active research area for more than 2 decades. − The interest in metal phosphinidenes originates not only from their high reactivity, which gives access to new phosphorus-containing molecules, organometallic derivatives, and new materials, but also from their potential in phosphorus-element bond synthesis and potentially useful catalytic applications. − Overall, these investigations have been mainly focused on the synthesis and reactivity studies of phosphinidene complexes of the d-block transition metals, − whereas the related terminal phosphinidene actinide complexes have been more or less ignored, which, however, leaves plenty of room to discover their intrinsic reactivity . An interesting actinide metal to start these investigations is thorium, which possesses a [Rn] 6d 2 7s 2 electronic ground state, and therefore reactivity similar to that of early transition metals might be anticipated, for which several complexes with MPR bonds are known .…”

A Base-Free Terminal Actinide Phosphinidene Metallocene: Synthesis, Structure, Reactivity, and Computational Studies

“…This development has been motivated by their rich chemistry and their potential utility as intermediates or catalysts in the preparation of phosphorus compounds, organometallic derivatives, and new materials . In this context, variations of the metals bound to the phosphinidene ligands results in specific changes in their structure and catalytic activity as well as chemical and physical properties. − Terminal phosphinidene metal complexes with a MPR double bond are highly reactive, resulting not only in new phosphorus-containing molecules but also more efficient phosphorus–element bond synthesis and useful catalytic transformations. − Nevertheless, while the reactivity and properties of the terminal phosphinidenes of d-transition metals are now well explored and understood, − the related terminal phosphinidene actinide complexes have been difficult to access, and therefore, their intrinsic reactivity remained virtually unexplored . Hence, only a few examples of terminal phosphinidene actinide complexes have been structurally authenticated so far, ,,− and steric effects imposed by the ligand exert a considerable influence on the formation of the terminal multiple-bonded actinide complexes, in general. , Thus, the development of novel actinide compounds with terminal phosphinidene units represents an interesting, yet challenging, synthetic target for which bulky ligands are a prerequisite.…”

Rare-earth mediated dihydrogen activation and catalytic hydrogenation

“…53 In an attempt to access a rare-earth metal terminal phosphinidene, the Chen group obtained a scandium complex 25 with a unique four-membered C-P-N-Sc moiety, which was reported to react with H2, O2, CO, phenylsilane, and pinacolborane. 54 In the case of H-H bond activation, the authors proposed that both the electrophilic scandium ion and nucleophilic trivalent phosphorus atom worked synergistically to cleave dihydrogen. Due to instability of the intermediate, a quick rearrangement took place leading to the final product 26 (Scheme 13).…”