Effective Binding of Methane Using a Weak Hydrogen Bond

Abstract

The weak hydrogen bond is an important type of noncovalent interaction, which has been shown to contribute to stability and conformation of proteins and large biochemical membranes, stereoselectivity, crystal packing, and effective gas storage in porous materials. In this work, we systematically explore the interaction of methane with a series of functionalized organic molecules specifically selected to exhibit a weak hydrogen bond with methane molecules. To enhance the strength of hydrogen bond interactions, the functional groups include electron-enriched sites to allow sufficient polarization of the C-H bond of methane. The binding between nine functionalized benzene molecules and methane has been studied using the second order Møller-Plesset perturbation theory to reveal that benzenesulfonic acid (C6H5-SO3H) and phenylphosphonic acid (C6H5-PO3H2) have the greatest potential for efficient methane capture through hydrogen bonding interactions. Both acids exhibit efficient binding potential with up to three methane molecules. For additional insight, the atomic charge distribution associated with each binding site is presented.

Computational Evaluation of the Impact of Incorporated Nitrogen and Oxygen Heteroatoms on the Affinity of Polyaromatic Ligands for Carbon Dioxide and Methane in Metal–Organic Frameworks

“…Furthermore, since methane molecules bound directly above the aromatic core and via weak hydrogen bonding on the edges of the ligand are unlikely to introduce any steric clashes, the inclusion of heterocyclic ligands introduces the potential for cooperative methane binding, such as that observed in the case of some functionalized benzene systems. 40 While the location of the strongest methane binding sites on the carbocyclic L3 c and heterocyclic L3 h linkers remained very similar, the introduction of additional O-heteroatoms in the longer L5 h linker significantly alters the preferred CH 4 binding locations. For the CH 4 −L5 h system, the strongest interactions were observed when methane was located directly above the oxygen-containing, electron-rich central ring of the linker (Figure 9).…”

“…While the introduction of N-heteroatoms to the L3 system causes methane to be slightly less strongly bound on locations above the ring system, the creation of additional binding sites via hydrogen bonding suggests that the heterocyclic linker is a more attractive candidate for low-pressure methane adsorption than its carbocyclic equivalent. Furthermore, since methane molecules bound directly above the aromatic core and via weak hydrogen bonding on the edges of the ligand are unlikely to introduce any steric clashes, the inclusion of heterocyclic ligands introduces the potential for cooperative methane binding, such as that observed in the case of some functionalized benzene systems …”

Analyzing Gas Adsorption in an Amide-Functionalized Metal Organic Framework: Are the Carbonyl or Amine Groups Responsible?

“…The six methane carbon sites are classified based on local environment: C16 A and C16 B are close to the amide oxygen and termed amide-proximate (Figure b-II), whereas C15 A , C15 B , C15 C and C15 D are close to the carboxylate oxygen atoms and classified as carboxylate-proximate (Figure b-III and IV). Based on this data and prior work, it appears methane adsorption proceeds via weak hydrogen bonding between methane hydrogen atoms and the neighboring amide and carboxylate oxygen atoms, but this is difficult to confirm without accurate hydrogen positions.…”

Electronic Structure and d–d Spectrum of Metal–Organic Frameworks with Transition-Metal Ions

“…Metal–organic frameworks (MOFs) are actively studied crystalline porous materials , with a wide range of remarkable properties and applications which include gas storage, separation, ,− and sensing, heterogeneous catalysis, , biomedical imaging, and other areas. MOFs containing transition-metal (TM) ions represent a particularly interesting class since their complex electronic structure caused by the presence of open d-shells yields unique responses to the adsorption of small molecules, − interaction with magnetic field, and temperature changes. , Changes in optical, electrical, and magnetic properties of MOFs caused by the adsorption of guest molecules have been actively used in sensing applications. ,,, They can be associated with the spin-crossover phenomenon, in which spin of the ground state of a d-shell switches due to an external perturbation, in this case, due to rearrangement of the coordination sphere of TM upon adsorption.…”

“…Metal–organic frameworks (MOFs) are actively studied crystalline porous materials 1 , 2 with a wide range of remarkable properties 3 and applications which include gas storage, 4 5 6 7 separation, 4 , 8 − 15 and sensing, 16 heterogeneous catalysis, 17 , 18 biomedical imaging, 19 and other areas. MOFs containing transition-metal (TM) ions represent a particularly interesting class since their complex electronic structure caused by the presence of open d-shells yields unique responses to the adsorption of small molecules, 20 − 28 interaction with magnetic field, 29 and temperature changes.…”