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Combined computational and chemometric study of 1 H ‐indole‐3‐acetic acid
Author(s) -
Kiralj Rudolf,
Ferreira Márcia M. C.
Publication year - 2003
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.10693
Subject(s) - chemistry , dimer , hydrogen bond , ab initio , density functional theory , computational chemistry , bond length , molecular geometry , ring (chemistry) , coupled cluster , basis set , natural bond orbital , monomer , ab initio quantum chemistry methods , molecule , organic chemistry , polymer
Geometries of free 1 H ‐indole‐3‐acetic acid (IAA) and IAA hydrogen bond dimer were optimized at several computational levels: molecular mechanics, semiempirical methods, ab initio density functional theory with SVWN (Slater‐Vosko‐Wilk‐Nusair) and Becke's three‐parameter exchange functional and the gradient‐corrected functional of Lee, Yang, and Paar (B3LYP) functionals, and Hartree–Fock (HF). Bond length matrices X ( mxn ) (m = number of bonds, n = number of experimental determinations and theoretical calculations) and their transposes X ( nxm ) for IAA monomer, IAA dimer, and hydrogen bond ring (angles included) were analyzed using principal component analysis (PCA) and hierarchical cluster analysis (HCA). Ab initio methods prove to be superior to molecular mechanics and semiempirical methods: SVWN methods are the best for monomer, and B3LYP are best for dimer geometry optimization. The B3LYP and HF methods can be used equally well for optimization of the dimer ring geometry. Other hydrogen bond and aromaticity structural parameters exhibit preference either for B3LYP or SVWN methods. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem 95: 237–251, 2003