TY  - JOUR
A1  - Debatin, Franziska
A1  - Behrens, Karsten
A1  - Weber, Jens
A1  - Baburin, Igor A.
A1  - Thomas, Arne
A1  - Schmidt, Johannes
A1  - Senkovska, Irena
A1  - Kaskel, Stefan
A1  - Kelling, Alexandra
A1  - Hedin, Niklas
A1  - Bacsik, Zoltan
A1  - Leoni, Stefano
A1  - Seifert, Gotthard
A1  - Jäger, Christian
A1  - Günter, Christina
A1  - Schilde, Uwe
A1  - Friedrich, Alwin
A1  - Holdt, Hans-Jürgen
T1  - An isoreticular family of microporous metal-organic frameworks based on zinc and 2-substituted imidazolate-4-amide-5-imidate Syntheses, structures and properties
JF  - Chemistry - a European journal
N2  - We report on a new series of isoreticular frameworks based on zinc and 2-substituted imidazolate-4-amide-5-imidate (IFP-14, IFP=imidazolate framework Potsdam) that form one-dimensional, microporous hexagonal channels. Varying R in the 2-substitued linker (R=Me (IFP-1), Cl (IFP-2), Br (IFP-3), Et (IFP-4)) allowed the channel diameter (4.01.7 angstrom), the polarisability and functionality of the channel walls to be tuned. Frameworks IFP-2, IFP-3 and IFP-4 are isostructural to previously reported IFP-1. The structures of IFP-2 and IFP-3 were solved by X-ray crystallographic analyses. The structure of IFP-4 was determined by a combination of PXRD and structure modelling and was confirmed by IR spectroscopy and 1H MAS and 13C CP-MAS NMR spectroscopy. All IFPs showed high thermal stability (345400?degrees C); IFP-1 and IFP-4 were stable in boiling water for 7 d. A detailed porosity analysis was performed on the basis of adsorption measurements by using various gases. The potential of the materials to undergo specific interactions with CO2 was investigated by measuring the isosteric heats of adsorption. The capacity to adsorb CH4 (at 298 K), CO2 (at 298 K) and H2 (at 77 K) at high pressure were also investigated. In situ IR spectroscopy showed that CO2 is physisorbed on IFP-14 under dry conditions and that both CO2 and H2O are physisorbed on IFP-1 under moist conditions.
KW  - adsorption
KW  - metal- organic frameworks
KW  - microporous materials
KW  - N
KW  - O ligands
KW  - zinc
Y1  - 2012
U6  - https://doi.org/10.1002/chem.201200889
SN  - 0947-6539
VL  - 18
IS  - 37
SP  - 11630
EP  - 11640
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Cherstvy, Andrey G.
T1  - Critical polyelectrolyte adsorption under confinement Planar slit, cylindrical pore, and spherical cavity
JF  - Biopolymers
N2  - We explore the properties of adsorption of flexible polyelectrolyte chains in confined spaces between the oppositely charged surfaces in three basic geometries. A method of approximate uniformly valid solutions for the Green function equation for the eigenfunctions of polymer density distributions is developed to rationalize the critical adsorption conditions. The same approach was implemented in our recent study for the inverse problem of polyelectrolyte adsorption onto a planar surface, and on the outer surface of rod-like and spherical obstacles. For the three adsorption geometries investigated, the theory yields simple scaling relations for the minimal surface charge density that triggers the chain adsorption, as a function of the Debye screening length and surface curvature. The encapsulation of polyelectrolytes is governed by interplay of the electrostatic attraction energy toward the adsorbing surface and entropic repulsion of the chain squeezed into a thin slit or small cavities. Under the conditions of surface-mediated confinement, substantially larger polymer linear charge densities are required to adsorb a polyelectrolyte inside a charged spherical cavity, relative to a cylindrical pore and to a planar slit (at the same interfacial surface charge density). Possible biological implications are discussed briefly in the end.
KW  - polymers
KW  - adsorption
KW  - electrostatics
KW  - confinement
Y1  - 2012
U6  - https://doi.org/10.1002/bip.22023
SN  - 0006-3525
VL  - 97
IS  - 5
SP  - 311
EP  - 317
PB  - Wiley-Blackwell
CY  - Hoboken
ER  -