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A computational study of a host‐guest complex
Author(s) -
Sabio Michael,
Topiol Sid
Publication year - 1997
Publication title -
journal of molecular recognition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.401
H-Index - 79
eISSN - 1099-1352
pISSN - 0952-3499
DOI - 10.1002/(sici)1099-1352(199707/08)10:4<159::aid-jmr359>3.0.co;2-b
Subject(s) - ab initio , pyrazine , molecule , acridine , computational chemistry , superposition principle , chemistry , relaxation (psychology) , quantum chemical , quantum chemistry , ab initio quantum chemistry methods , supramolecular chemistry , chemical physics , crystallography , physics , stereochemistry , quantum mechanics , organic chemistry , psychology , social psychology
The geometry and energetics of a complex involving pyrazine and an acridine diacid cleft‐like host designed by Rebek were investigated at several levels of theory. Molecular mechanics (using the Tripos and CHARMm force fields), semiempirical quantum chemical approaches (with the AM1 and PM3 methods), and an ab initio quantum chemical method (RHF/STO‐3G) were used in the complete relaxation of the complex. The geometry of the complex optimized by the RHF/STO‐3G method is in excellent agreement with a published X‐ray structure; upon superposition, the rms deviation between the corresponding cleft heavy atoms is only 0.17 Å and the pyrazine molecules are superimposable. In addition, ab initio quantum chemical techniques were used to study the complex when the cleft is modeled by a pair of acetic acid molecules. All the calculations presented herein support a two‐point interaction mechanism. The similarities found in the results for the full complex and the truncated model are consistent with a purely structural role for the acridine linker of the host. © 1997 John Wiley & Sons, Ltd.