title: Density functional theory meta-GGA + U study of water incorporation in the metal-organic framework material Cu-BTC.
abstract: Water absorption in the metal-organic framework (MOF) material Cu-BTC, up to a concentration of 3.5 H2O per Cu ion, is studied via density functional theory at the meta-GGA + U level. The stable arrangements of water molecules show chains of hydrogen-bonded water molecules and a tendency to form closed cages at high concentration. Water clusters are stabilized primarily by a combination of water-water hydrogen bonding and Cu-water oxygen interactions. Stability is further enhanced by van der Waals interactions, electric field enhancement of water-water bonding, and hydrogen bonding of water to framework oxygens. We hypothesize that the tendency to form such stable clusters explains the particularly strong affinity of water to Cu-BTC and related MOFs with exposed metal sites.
authors.affiliation: Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA.
authors.forename: Eric
authors.initials: E
authors.lastname: Cockayne
authors.affiliation: Materials Measurement Science Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA.
authors.forename: Eric B
authors.initials: EB
authors.lastname: Nelson
mesh_terms: D000327:Adsorption; D003198:Computer Simulation; D003300:Copper / Q000737:chemistry; D055590:Electromagnetic Phenomena; D006860:Hydrogen Bonding; D007477:Ions / Q000737:chemistry; D000073396:Metal-Organic Frameworks; D008956:Models, Chemical; D009942:Organometallic Compounds / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry; D014867:Water / Q000737:chemistry*
chemical_list: D007477:Ions; D000073396:Metal-Organic Frameworks; D009942:Organometallic Compounds; C539834:bis(1,3,5-benzenetricarboxylate)tricopper(II); D014867:Water; D003300:Copper; D010100:Oxygen