Crystalline hydrogen-bonded supramolecular frameworks (HSFs) as new class of proton conductive materials

Multi-Interactions in Ionic Liquids for Natural Product Extraction

“…There also exists hydrogen bonding between anion and cation in task specific ILs such as halogenated quaternary ammonium ionic liquids (i.e., N -trimethyl- N -propylammonium bis(trifluoromethylsulfonyl)imide ([N 3111 ][NTf 2 ]), bihydroxyethylbiethylammonium bromide ([NEt 2 (HE) 2 ]Br)), amino acid-based ionic liquids (i.e., L-proline trifluoroacetate ([L-Pro][CF 3 COO]), L-proline sulfate ([L-Pro] 2 [SO 4 ])), protic ionic liquids (i.e., [(CH 3 ) 3 NH][NO 3 ], dimethylammonium bromide ([(CH 3 ) 2 NH 2 ]Br)), etc. In these ILs, the cation and anion contain proton acceptor and donor sites, resulting in formation of an extended hydrogen bonding network [ 36 , 37 , 38 ]. The hydrogen bonding between the anion and cation expressed as + [A–H···B] − shows particular features in the geometric, electronic, and dynamic aspects, which is inherently different from that of the conventional hydrogen bonding in molecular solvents expressed as A–H···B [ 39 ].…”

“…]Br)), etc. In these ILs, the cation and anion contain proton acceptor and donor sites, resulting in formation of an extended hydrogen bonding network [36][37][38]. The hydrogen bonding between the anion and cation expressed as + [A-H•••B] − shows particular features in the geometric, electronic, and dynamic aspects, which is inherently different from that of the conventional hydrogen bonding in molecular solvents expressed as A-H•••B [39].…”

Hydrogen-bonded cobalt(ii)-organic framework: normal and reverse spin-crossover behaviours

“…Hydrogen-bonded metal-organic frameworks (H-MOFs) have a metal complex as a building unit, in which they are connected through H-bonding. [1][2][3][4][5][6][7][8][9][10][11] They have been applied to the molecular porous materials like the typical MOFs [12][13][14] and covalent organic frameworks (COFs). 15,16 The magnitude of Hbonding determines the flexibility between units and can be controlled via the electrostatic interactions between the donor and acceptor moieties.…”

Hybrid Nafion Membranes of Ionic Hydrogen-Bonded Organic Framework Materials for Proton Conduction and PEMFC Applications

“…In the past 2 decades, crystalline materials, such as metal–organic frameworks (MOFs), covalent organic frameworks (COFs), or hydrogen-bonded organic frameworks (HOFs), have attracted extensive attention because of their unlimited structural diversity and functional tunability. − Due to the ability to custom-design the ligands with carrier molecules, tailor pore environments, and understand proton-transport pathways at the molecular level, crystalline materials provide a new platform for proton-conducting materials. − However, most of these crystalline materials focus on the conduction of crystals, the research studies on PEMs and PEMFCs are rare. ,− Owing to the unique characteristics such as rich hydrogen-bonding network and solution machinability, crystalline HOFs render a promising platform for proton conductivity and PEM materials. − The ligands used to construct single-component HOFs such as −COOH and −NH 2 can use their own functional groups to form hydrogen bonds, − but these traditional HOFs connected by weak hydrogen bonds have poor stability and, in most cases, the structures collapse under medium and high temperature conditions. Different from single-component HOFs, ionic two-component HOFs (also known as charge-assisted hydrogen bond frameworks) showed good stability due to the various hydrogen bond types and electrostatic interactions.…”