Functionalization of Carbon Monoxide and tert‐Butyl Nitrile by Intramolecular Proton Transfer in a Bis(Phosphido) Thorium Complex

Abstract

We report intramolecular proton transfer reactions to functionalize carbon monoxide and tert‐butyl nitrile from a bis(phosphido) thorium complex. The reaction of (C5Me5)2Th[PH(Mes)]2, Mes=2,4,6‐Me3C6H2, with 1 atm of CO yields (C5Me5)2Th(κ2‐(O,O)‐OCH2PMes‐C(O)PMes), in which one CO molecule is inserted into each thorium–phosphorus bond. Concomitant transfer of two protons, formerly coordinated to phosphorus, are now bound to one of the carbon atoms from one of the inserted CO molecules. DFT calculations were employed to determine the lowest energy pathway. With tert‐butyl nitrile, tBuCN, only one nitrile inserts into a thorium–phosphorus bond, but the proton is transferred to nitrogen with one phosphido remaining unperturbed affording (C5Me5)2Th[PH(Mes)][κ2‐(P,N)‐N(H)C(CMe3)P(Mes)]. Surprisingly, reaction of this compound with KN(SiMe3)2 removes the proton bound to nitrogen, not phosphorus.

Divergent uranium- versus phosphorus-based reduction of Me3SiN3 with steric modification of phosphido ligands

“…In addition, the 1 H NMR spectrum showed the (C 5 Me 5 ) 1À resonance at À1.35 ppm, but another resonance integrating to 18 protons was detected at 10.3 ppm. A signal in the 31 P NMR spectrum at 518.0 ppm was located.…”

“…24 These complexes impart a mismatch between the hard, electropositive Lewis acidic actinide centre, and the so Lewis basic nature of phosphorus, and have been shown to afford unpredictable and unusual chemistry. [25][26][27][28][29][30][31][32][33][34] We recently showed that the U(III) complex, (C 5 Me 5 ) 2 U(THF) [P(SiMe 3 )(Mes)] reacts with Me 3 SiN 3 to form the U(VI) bis(imido) complex, (C 5 Me 5 ) 2 U(]NSiMe 3 ) 2 . 35 In order to prevent the formation of the bis(imido) complex, here, we used the mixed phosphido-methyl complexes (C 5 Me 5 ) 2 U(CH 3 )[P(SiMe 3 )(R)], R ¼ C 6 H 5 (Ph), 1; 2,4,6-Me 3 C 6 H 2 (Mes), 2.…”

Thorium(IV) and Uranium(IV) Phosphaazaallenes

“…Thus, they are less inclined to form strong interactions with ligands bearing soft-donor atoms such as phosphorus. Therefore, the actinide-phosphido bond should, and has been demonstrated, be relatively reactive [20][21][22][23][24][25][26][27][28][29][30].…”

Formation and Reactivity with tBuCN of a Thorium Phosphinidiide through a Combined Experimental and Computational Analysis

“…The activation of P–H bonds − is an essential step in hydrophosphination , and hydrodecoupling , reactions; however, the mechanisms by which metal complexes perform P–H activations are not fully understood. For example, in our work on the reactivity of actinide phosphido complexes, P–H bond activations via σ-bond metathesis are observed, − but other mechanisms by which P–H activations occur are less straightforward. − Generally, most of these metal-mediated activations involve mononuclear metal complexes, while multimetallic or cooperative examples are limited. , Acquiring further mechanistic insight into these bond activations is important to afford strategies for the functionalization of phosphines, , which are of interest for a wide array of applications. The reactivities of metal alkyl , and hydride − complexes, especially with electropositive metals, help to facilitate these bond activations, and thus a number of examples of P–H bond activation are known with f elements, nearly all involving lanthanide complexes. ,,− …”