Small Molecule Activation Mediated by a Thorium Terminal Imido Metallocene

Abstract

The base-free thorium terminal imido [η 5 -1,2,4-(Me 3 C) 3 C 5 H 2 ] 2 ThN(p-tolyl) (1) activates a variety of small molecules such as pyridine derivatives, amines, boranes, chlorosilane, elemental selenium, and α,β-unsaturated esters. Reaction of 1 with pyridine, pyridine N-oxide, 2-methylpyridine N-oxide, p-toluidine, Ph 2 NH, 9-borabicyclo[3.3.1]-nonane (9-BBN), PhSiH 2 Cl, elemental selenium, PhSeSePh, and methyl methacrylate (MMA) formed the amido pyridyl complexes [η 5 -1,2,

Insertion, protonolysis and photolysis reactivity of a thorium monoalkyl amidinate complex

“…The Th(1)–N(7) bond distance of 2.399(2) Å in 4 is very close to the Th–N bond distance of 2.389(2) Å observed by Walter and co-workers in [η 5 -1,2,4-(Me 3 C) 3 C 5 H 2 ] 2 Th(Cl)-[N( p -tolyl)SiH 2 Ph], which has a similar silyl amide environment. 44 The nitrogen atom of the amido exhibits a trigonal planar geometry (Σ∠ ≈ 360°), also consistent with Walter's complex. A series of NMR scale experiments revealed the thermal decomposition to be concentration dependent, with higher concentrations of 3 leading to the generation of the silyl amine ( p -tolyl)NH(SiMe 3 ) (as determined by 1 H NMR spectroscopy) and a mixture of unknown species (see Fig.…”

1,2-Addition and cycloaddition reactions of niobium bis(imido) and oxo imido complexes

“…While there are numerous examples of nitrene transfer chemistry involving p-loaded metal imido complexes, catalytic reactions without nitrene transfer are rare. High-valent transition metal complexes of groups 3-5 [39][40][41][42][43][44] and actinide 45,46 imido complexes have been shown to activate dihydrogen, silanes and/or boranes across imido bonds, but in all of these cases, only stoichiometric reactivity could be observed. A cationic V bis(imido) complex was shown to catalytically hydrogenate alkynes to alkenes via a 1,2-addition and 1,2-elimination pathway.…”

A Relativistic DFT Probe of Thorium and Protactinium Complexes Supported by Heterocalix[4]arene and Redox Properties of Early‐Middle Actinides

“…In contrast, the Th(III) complex remains rare due to the greatly negative reduction potential −2.35 V (vs. Fc + /Fc), where 0.65 V was used to correct the original value (vs. NHE) . Although recent advance in the synthetic technique leads to more accessibility of Th III complexes, the study of redox properties of Th VI /Th III complexes remains underexplored, to our best of knowledge. For example, above E 0 of Th VI/III ions in water is the only available value, and moreover was obtained with the assistance of electron‐transfer and f ‐ d absorption bands .…”

“…The molecular chemistry of thorium is dominated by the IV oxidation state in contrast to III and II ones. Although extremely low reduction potentials of Th IV/III (‐3.0 V versus NHE) and Th III/II (‐4.9 V) were presumed, several Th III complexes and even one Th II complex have been synthesized and structurally characterized via massive efforts . In addition to commonly used cyclopentadienyl (Cp), cyclooctatetraenyl (COT) and their substituted derivatives, a small‐cavity macrocyclic trans ‐calix[2]pyrrole[2]benzene (H 2 L, Figure ), synthesized by the Sessler's group, has been found suitable for chelating Th IV .…”

“…Although extremely low reduction potentials of Th IV/III (‐3.0 V versus NHE) and Th III/II (‐4.9 V) were presumed, several Th III complexes and even one Th II complex have been synthesized and structurally characterized via massive efforts . In addition to commonly used cyclopentadienyl (Cp), cyclooctatetraenyl (COT) and their substituted derivatives, a small‐cavity macrocyclic trans ‐calix[2]pyrrole[2]benzene (H 2 L, Figure ), synthesized by the Sessler's group, has been found suitable for chelating Th IV . Interestingly, the flexibility of H 2 L allows its two binding pockets (BP), bis (arene) (marked as Ar L) and bis (pyrrolide) ( Pl L), to hold the actinide ion.…”