Infrared Spectroscopy Evidence of Weak Interactions in Frustrated Lewis Pairs Formed by Tris(pentafluorophenyl)borane

Marques, Leandro Ramos; Ando, Rômulo Augusto

doi:10.1002/cphc.202200715

Cited by 6 publications

(1 citation statement)

References 33 publications

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“…These C-H•••F interactions for a range of FLP systems were corroborated by non-covalent interaction (NCI) analysis. 20,21 The favourable stabilisation energy in FLP systems is significant (approximately 10-15 kcal mol -1 ), and the inclusion of implicit solvent corrections only slightly reduces this stabilisation. 22 However, the enthalpic stabilisation is opposed by the entropic cost of adduct formation, and this is consistent with difficulties in observing the encounter complex experimentally.…”

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confidence: 99%

The Active Encounter Complex in Frustrated Lewis Pair Chemistry

Littlewood,

Liu,

Chen

et al. 2023

Preprint

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Sustainable catalysts based on main-group elements have emerged as alternatives to expensive and environmentally unfriendly precious metal systems. Frustrated Lewis pairs (FLPs) are precluded from forming a classical Lewis adduct, and have displayed remarkably versatile reactivity in the fields of small-molecule activation and catalysis. The initial reaction of the acid, base and small molecule (e.g. H2) is formally termolecular, but the viability of this reaction is rationalised by the pre-association of the acid and base in an encounter complex. However, there is no experimental methodology to study the active encounter complex, i.e. the pre-associated complex that is in the correct orientation for small-molecule activation. Here we show that the charge-transfer band between PMes3 and B(C6F5)3 can be analysed by supramolecular techniques to provide the key thermodynamic parameter, Ka, for the active encounter complex. We also demonstrate that a higher concentration of active encounter complex in solution leads to a faster activation of hydrogen. This method enables researchers to directly probe the complex that underpins FLP small-molecule activation and subsequent catalysis, and will aid the design of more active sustainable catalysts.

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confidence: 99%

The Active Encounter Complex in Frustrated Lewis Pair Chemistry

Littlewood,

Liu,

Chen

et al. 2023

Preprint

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IGMH‐based research on the intramolecular weak interaction of TKX‐50

Yang,

Dong,

et al. 2024

Propellants Explo Pyrotec

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To further comprehensively study the intramolecular weak interaction of the gaseous TKX‐50 molecule, the two conformations of the TKX‐50 molecule were analyzed via the Independent Gradient Model based on the Hirshfeld Partition (IGMH) method based on the B3LYP/6‐311 g (d,p) level for geometry optimization and for single point energy. The conclusions manifest that the weak interactions between these fragments are mainly composed of hydrogen bonds and van der Waals interactions. From the strength of inter‐fragment interactions formed by contributing atomic pairs and their percentage contributions, these H bonds, together with dispersion‐dominated weak interactions provided by non‐direct facing atomic pairs near these H bonds, dominate the inter‐fragment interaction resulting in the stability of the molecular structure. Meanwhile, the weak interactions enclosed by end‐atoms of two fragments not only include the contributions provided by inter‐fragment atomic pairs of two fragments but also include the contributions provided by intra‐fragment atomic pairs of fragment 1. For conformation II, due to the H transfer between fragments, a pair of symmetric H bonds at the corresponding regions are extremely strong to reach the level of covalent bond while the two groups −OH at the other end become looser, resulting in conformation II own lower energy. Differences in inter‐fragment interactions between two conformations were essentially brought by the stronger electron‐withdrawing ability of atom O than that of atom N.

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Supported Recyclable Metal-free Frustrated Lewis Pair Catalyst for Catalytic Hydrogenation of Substituted Pyridines to Piperidines

Ma,

Tang

2024

Chem. Res. Chin. Univ.

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Infrared Spectroscopy Evidence of Weak Interactions in Frustrated Lewis Pairs Formed by Tris(pentafluorophenyl)borane

Cited by 6 publications

References 33 publications

The Active Encounter Complex in Frustrated Lewis Pair Chemistry

The Active Encounter Complex in Frustrated Lewis Pair Chemistry

IGMH‐based research on the intramolecular weak interaction of TKX‐50

Supported Recyclable Metal-free Frustrated Lewis Pair Catalyst for Catalytic Hydrogenation of Substituted Pyridines to Piperidines

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