Alkyl‐Alkyl Interactions in the Periphery of Supramolecular Entities: From the Evaluation of Weak Forces to Applications

Giese, Michael; Albrecht, Markus

doi:10.1002/cplu.202000077

Cited by 19 publications

(10 citation statements)

References 109 publications

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“…This is particularly true for molecules in solution, where it is often assumed that LD is overridden by solvent effects . Recently, this view has been carefully refined, − but an analysis of a nonpolar molecular balance that avoids additional interactions arising from (local) dipoles is still lacking . Hence, by utilizing a pure hydrocarbon balance, we show here that solvents do affect LD interactions, mostly through changes in the solvent reorganization entropy, but that LD enthalpically remains constant and comparable to gas-phase values.…”

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confidence: 72%

Intramolecular London Dispersion Interactions Do Not Cancel in Solution

et al. 2020

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We present a comprehensive experimental study of a di-t-butyl-substituted cyclooctatetraene-based molecular balance to measure the effect of 16 different solvents on the equilibrium of folded versus unfolded isomers. In the folded 1,6-isomer, the two t-butyl groups are in close proximity (H•••H distance ≈ 2.5 Å), but they are far apart in the unfolded 1,4-isomer (H•••H distance ≈ 7 Å). We determined the relative strengths of these noncovalent intramolecular σ−σ interactions via temperature-dependent nuclear magnetic resonance measurements. The origins of the interactions were elucidated with energy decomposition analysis at the density functional and ab initio levels of theory, pinpointing the predominance of London dispersion interactions enthalpically favoring the folded state in any solvent measured. * sı Supporting InformationThe Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/jacs.0c09597.Comparison with previous measurements as well as synthetic and computational details (PDF)

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confidence: 72%

Intramolecular London Dispersion Interactions Do Not Cancel in Solution

et al. 2020

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“…However, one should be able to identify a stronger binding motif in the thermodynamically favored HT phase, which is not evident in Figure . In fact, the two H-Mabiq molecules forming the bright four-lobed structures would interact with each other by generally weak methyl–methyl interactions. − Consequently, a convincing rationale for the stabilization of the HT phase upon heating must be sought elsewhere.…”

Section: Resultsmentioning

confidence: 99%

The Flexible On-Surface Self-Assembly of a Low-Symmetry Mabiq Ligand: An Unconventional Metal-Assisted Phase Transformation on Ag(111)

et al. 2021

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The self-assembly of metal−organic complexes and networks of increasing complexity on solid surfaces is important for their application in a variety of fields, such as catalysis, sensing, and molecular magnetism. Here, we have selected a low-symmetry, freebase macrocyclic biquinazoline ligand, H-Mabiq, which upon metalation has the potential to incorporate cations in two different coordination sites, affording multi-valency and multielectron transfer capacity. We show that H-Mabiq molecules readily self-assemble onto the Ag(111) surface at room temperature, forming a well-ordered monolayer of closely packed molecules. Upon increasing the temperature, a new phase with a different long-range order and molecular packing is obtained. By means of scanning tunneling microscopy and photoelectron spectroscopy, we show that this new phase is characterized by a distinctive silver-bridged dimeric motif, entailing a Ag adatom accommodated at the peripheral coordination site of two opposing H-Mabiq molecules. Thus, the present work reveals the ability of the bio-inspired Mabiq ligands to form surface-confined two-dimensional assemblies incorporating metal adatoms. The results bode promise for the use of metalcontaining Mabiq compounds to engineer regular bimetallic arrays with atomic precision.

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“…Regarding the possible solvent–gelator interactions, these two solvents could have interacted with the oleyl chain of the gelator molecule without disrupting the gelator H-bonding network through amides. In the case of n-alkanes, we hypothesized that the solvent molecules intercalated between the gelator alkyl chains to form a layered structure that was held together through attractive London interactions. , The lamellar long-range self-assembly of the gelators was still maintained and not disrupted by the solvent molecules with the same arrangement as the crystalline powder, as shown by the diffraction pattern. Regarding o -xylene gel, the gelator molecules were in a disordered state and no diffraction pattern was observed, so the gel was amorphous.…”

Section: Resultsmentioning

confidence: 99%

Effect of Solvent on the Mechanical and Structural Properties of N-Alkyldiamide Organogels

et al. 2021

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Here, we study organogels prepared thanks to a new organogelator, the N-oleyldiamide molecule, which shows a remarkable propensity to gelify a large scope of solvents, from aprotic to high protic solvents. The solvent plays a key role in the formation and stability of supramolecular self-assemblies. However, the understanding and the control of its effects can be complex as many parameters are a priori involved. This study aims to understand the effect of solvent on the structures of organogels and on their final mechanical properties. Five solvent classes have been selected ranking from low protic to high protic, according to the Hansen H-bond parameter δh. The solvent proticity appears to be one of the main parameters that affect the organogel internal structure and therefore the final rheological properties. For a given organogelator fraction, the terminal elastic modulus measured by oscillatory rheology is observed to increase significantly with the Hansen H-bond solvent parameter δh. Materials of different mechanical properties are then shown to display various structures, which are investigated thanks to cryo-SEM. Besides, wide-angle X-ray scattering (WAXS) has been used to probe the gelator organization at the molecular scale with regard to the solvent nature, to understand the supramolecular self-assembly of this promising molecule.

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Alkyl‐Alkyl Interactions in the Periphery of Supramolecular Entities: From the Evaluation of Weak Forces to Applications

Cited by 19 publications

References 109 publications

Intramolecular London Dispersion Interactions Do Not Cancel in Solution

Intramolecular London Dispersion Interactions Do Not Cancel in Solution

The Flexible On-Surface Self-Assembly of a Low-Symmetry Mabiq Ligand: An Unconventional Metal-Assisted Phase Transformation on Ag(111)

Effect of Solvent on the Mechanical and Structural Properties of N-Alkyldiamide Organogels

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