Unraveling differences in aluminyl and carbene coordination chemistry: bonding in gold complexes and reactivity with carbon dioxide

Belpassi³

et al. 2023

Dalton Trans.

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Section: Table 1 Iao Partial Charge Distributions Of Thesupporting

confidence: 91%

mentioning

confidence: 99%

How reduced are nucleophilic gold complexes?

Leach

Belpassi³

et al. 2023

Dalton Trans.

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“…A second non-negligible component can be envisaged (Δρ2', Figure 2b and S6), representing a charge transfer from the H2 to the [ t Bu3PAuAl(NON)] LUMO, mainly composed by the empty 3pz orbital of Al. Notably, this NOCV description of the H2-[ t Bu3PAuAl(NON)] is strongly reminiscent of both the CO2-[ t Bu3PAuAl(NON)] interaction (see Refs [2][3][4][5] ) and the H2-[RGeGeR] interaction reported by Frenking and coworkers, where the digermyne, by employing the σ Ge-Ge HOMO and the 4pz-centred LUMO, interacts with the H2 LUMO and HOMO, respectively. [12] Surprisingly, despite remarkable structural and energetic differences, the H2-[ t Bu3PAuAl(NON)] interactions at TS I Au are qualitatively similar to those at TS IV Au.…”

mentioning

confidence: 60%

“…[1] We have thoroughly discussed that the driving force of this reactivity is the presence of an electron-sharing, weakly polarized Au-Al bond acting as a nucleophilic site inducing a cooperative diradical-like reactivity. [2][3][4][5] Shortly after, analogous reactivity has been reported to occur for copper-and silver-aluminyl complexes, for which, however, the reaction proceeds towards the formation of carbonate complexes with CO extrusion. [6] Scheme 1. a) Similar reactivity of [ t Bu3PAuAl(NON)] (NON = 4,5-bis(2,6diisopropylanilido) -2,7-di-tert-butyl-9,9-dimethylxanthene) complex 1 and (Ar*)(SiMe3)GeGe(Ar*)(SiMe3) complex 3 with CO2.…”

mentioning

confidence: 69%

“…In a recent work, we have shown that gold aluminyl complexes, unlike gold carbene analogues featuring a dative Au-C bond, are able to react with CO2. [4] In this scenario the interest in exploring the reactivity of gold-aluminyl complexes towards H2 naturally arises. The electron-sharing nature of the Au-Al bond in complex 1 allowed to rationalize its reactivity with CO2, [2] in close resemblance with that of digermyne complex 3, thus we reasoned that the same bonding model may also favor the reaction of complex 1 with H2 analogous to that of complexes 5.…”

mentioning

confidence: 99%

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Radical-like reactivity for dihydrogen activation by coinage metal-aluminyl complexes: computational evidence inspired by experimental main group chemistry

Belpassi²,

Belanzoni

2022

Preprint

The computational study of an unprecedented reactivity of coinage metal-aluminyl complexes with dihydrogen is reported. In close resemblance to Group 14 dimetallenes and dimetallynes, the complexes are predicted to activate H2 under mild conditions. Two different reaction pathways are found disclosing a common driving force, i.e., the nucleophilic behavior of the electron-sharing M-Al (M = Cu, Ag, Au) bond, which enables a cooperative and diradical-like mechanism. This mode of chemical reactivity emerges as a new paradigm for dihydrogen activation and calls for an experimental feedback.

Widening the Landscape of Small Molecule Activation with Gold‐Aluminyl Complexes: A Systematic Study of E−H (E=O, N) Bonds, SO₂ and N₂O Activation

Belpassi²,

Belanzoni

2023

Chemistry A European J

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The electronic features of gold-aluminyl complexes have been thoroughly explored. Their similarity with Group 14 dimetallenes and other metal-aluminyl complexes suggests that their reactivity with small molecules beyond carbon dioxide could be accessed. In this work, the reactivity of the [ t Bu 3 PAuAl(NON)] (NON = 4,5-bis(2,6 diisopropylanilido)-2,7-ditert-butyl-9,9-dimethylxanthene) complex towards water, ammonia, sulfur dioxide and nitrous oxide is computationally explored. The reaction mechanisms computed for each substrate strongly suggest that all activation processes are in principle experimentally feasible. Electronic structure analysis highlights that, in all cases, the reactivity is driven by the presence of the poorly polarized electron-sharing goldaluminyl bond, which induces a radical-like reactivity of the complex towards all the substrates. A flat topology of the potential energy surface (PES) has been found for the reaction with N 2 O, where two almost isoenergetic transition states can be located along the same reaction coordinate with different geometries, suggesting that the N 2 O binding mode may not be a good indicator of the nature of N 2 O activation in a cooperative bimetallic reactivity. In addition, the catalytic potentialities of these complexes have been explored in the framework of nitrous oxide reduction. The study reveals that the [ t Bu 3 PAuAl(NON)] complex might be an efficient catalyst towards oxidation of phosphines (and boranes) via N 2 O reduction. These findings underline recurring trends in the novel chemistry of gold-aluminyl complexes and call for experimental feedbacks.