The formation of ultrathin films of Rh-based porous metal− organic polyhedra (Rh-MOPs) by the Langmuir−Blodgett method has been explored. Homogeneous and dense monolayer films were formed at the air− water interface either using two different coordinatively alkyl-functionalized Rh-MOPs (HRhMOP(diz) 12 and HRhMOP(oiz) 12 ) or by in situ incorporation of aliphatic chains to the axial sites of dirhodium paddlewheels of another Rh-MOP (OHRhMOP) at the air−liquid interface. All these Rh-MOP monolayers were successively deposited onto different substrates in order to obtain multilayer films with controllable thicknesses. Aliphatic chains were partially removed from HRhMOP(diz) 12 films post-synthetically by a simple acid treatment, resulting in a relevant modification of the film hydrophobicity. Moreover, the CO 2 /N 2 separation performance of Rh-MOPsupported membranes was also evaluated, proving that they can be used as selective layers for efficient CO 2 separation.

The surface tension at the liquid−air interface of eight binary mixtures formed by N,N-dimethylacetamide and n-alkanols (from methanol to 1-pentanol) or 2-alkanols (from 2-propanol to 2-pentanol) was studied at three different temperatures (283.15, 298.15, and 313.15 K) and a pressure of 0.1 MPa. Surface tension deviations were also calculated. Moreover, the excess molar enthalpies for all of these mixtures were measured at T = 298.15 K and a pressure of 0.1 MPa. Both deviation and excess functions were correlated with the mole fraction by means of the Redlich−Kister equation. The surface tension deviations are found to be positive for the system containing methanol, sigmoidal for ethanol and negative for the rest of the alkanols. With regard to excess molar enthalpies, negative values are found for the system containing methanol, sigmoidal values for ethanol, and positive values for the rest of the alkanols.