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Enzyme
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Gene/Protein
Disease
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Drug
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Target Concepts:
Gene/Protein
Disease
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Enzyme
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Query: EC:3.4.16.2 (
PCP
)
3,761
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The gate-opening adsorption mechanism and sigmoidal adsorption isotherm were theoretically investigated taking CO
2
adsorption into porous coordination polymers, [Fe(ppt)
2
]
n
(
PCP
-N, Hppt = 3-(2-pyrazinyl)-5-(4-pyridyl)-1,2,4-triazole) and [Fe(dpt)
2
]
n
(
PCP
-C, Hdpt = 3-(2-pyridinyl)-5-(4-pyridyl)-1,2,4-triazole) as examples, where the hybrid method consisting of dispersion-corrected DFT for infinite
PCP
and a post-Hartree-Fock (SCS-MP2 and CCSD(T)) method for the cluster model was employed.
PCP
-N has site I (one-dimensional channel), site II (small aperture to site I), and site III (small pore) useful for CO
2
adsorption. CO
2
adsorption at site I occurs in a one by one manner with a Langmuir adsorption isotherm. CO
2
adsorption at sites II and III occurs through a gate-opening adsorption mechanism, because the crystal deformation energy ( E
DEF
) at these sites is induced largely by the first CO
2
adsorption but induced much less by the subsequent CO
2
adsorption. Interestingly, nine CO
2
molecules are adsorbed simultaneously at these sites because a large E
DEF
cannot be overcome by adsorption of one CO
2
molecule but can be by simultaneous adsorption of nine CO
2
molecules. For such CO
2
adsorption, the Langmuir-Freundlich sigmoidal adsorption isotherm was derived from the equilibrium equation for CO
2
adsorption. A very complicated CO
2
adsorption isotherm, experimentally observed, is reproduced by combination of the Langmuir and Langmuir-Freundlich adsorption isotherms. In
PCP
-C, CO
2
adsorption occurs only at site I with the Langmuir adsorption isotherm. Sites II and III of
PCP
-C cannot be used for CO
2
adsorption because a very large E
DEF
cannot be overcome by simultaneous adsorption of nine CO
2
molecules. Factors necessary for gate-opening adsorption mechanism are discussed on the basis of differences between
PCP
-N and
PCP
-C.
...
PMID:Theoretical Insight into Gate-Opening Adsorption Mechanism and Sigmoidal Adsorption Isotherm into Porous Coordination Polymer. 3026 69
