Publication
Title
Interactions of an asymmetric amine with a symmetric Cusalen complex : an EPR/ENDOR and HYSCORE investigation
Author
Abstract
Single enantiomers of R-/S-methylbenzylamine (MBA) were found to selectively form adducts with the chiral non-C2 symmetric Cusalen complex N-(3,5-di-tert-butylsalicylidene)-N′-(salicylidene)-cyclohexane-1,2-diamine copper(II), hereafter labelled [Cu(3)]. The g/A spin Hamiltonian parameters of this Cu(II) complex showed a decrease in symmetry from axial to rhombic upon formation of the [Cu(3)] + MBA adducts. The selectivity in enantiomeric discrimination was found to be only 59 ± 5% in favour of the heterochiral R,R′-[Cu(3)] + S-MBA and S,S′-[Cu(3)] + R-MBA adducts. This was directly evidenced by W-band EPR spectroscopy. The observed low selectivity for enantiomer discrimination is primarily attributed to the loss of the bulky tert-butyl groups from the 3,5 positions of [Cu(3)] compared to the parent N,N′-bis(3,5-di-tert-butylsalicylidene)-cyclohexane-1,2-diamine copper(II) ligand (labelled [Cu(1)]). The structure of the [Cu(3)] complex in the presence and absence of coordinating amine was further investigated by analysis of the ligand hyperfine interactions, as revealed through Q-band CW-ENDOR, X-band Davies ENDOR and HYSCORE. 1H couplings from the NH2 group of the amine, observed by ENDOR and HYSCORE, provided direct evidence of amine coordination.
Language
English
Source (journal)
Physical chemistry, chemical physics / Royal Society of Chemistry [London] - Cambridge, 1999, currens
Publication
Cambridge : 2011
ISSN
1463-9076 [print]
1463-9084 [online]
Volume/pages
13:45(2011), p. 20427-20434
ISI
000296871500049
Full text (Publisher's DOI)
Full text (publisher's version - intranet only)
UAntwerpen
Faculty/Department
Research group
Publication type
Subject
Affiliation
Publications with a UAntwerp address
External links
Web of Science
Record
Identification
Creation 23.01.2012
Last edited 01.12.2017
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