Solid-State NMR Study of Paramagnetic Bis(alaninato-κ2N,O)copper(II) and Bis(1-amino(cyclo)alkane-1-carboxylato-κ2N,O)copper(II) Complexes: Reflection of Stereoisomerism and Molecular Mobility in 13C and 2H Fast Magic Angle Spinning Spectra

Gábor Szalontai, Róbert Csonka, G. Speier, J. Kaizer, Jasmina Sabolović

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Solid-state stereochemistry and mobility of paramagnetic copper(II) complexes formed by aliphatic amino acids (L-alanine, D,L-alanine, 1-amino-2-methyl-alanine) and 1-amino(cyclo)alkane-1-carboxylic acids (alkane = propane, butane, pentane, hexane) as bidentate ligands has been studied by 13C and 2H solid-state fast magic angle spinning (MAS) NMR spectroscopy. We examined the prospective method to characterize solid-state paramagnetic compounds in a routine way. Both 13C and 2H MAS spectra can distinguish D,L and L,L diastereomers of natural and polydeuterated bis([Dn]alaninato)copper(II) (n = 0, 2, 8) complexes with axial and/or equatorial methyl positions (conformations) primarily due to different Fermi-contact (FC) contributions. The three-bond hyperfine couplings clearly show Karplus-like dependence on the torsional angles which turned out to be a useful assignment aid. Density functional theory calculations of the FC term and crystal structures were also used to aid the final assignments. The correlations obtained for bis(alaninato-κ2N,O)copper(II) complexes were successfully used to characterize other complexes. The usefulness of the 2H MAS spectra of the deuterated complexes was underlined. Even the spectra of the easily exchangeable amine protons contained essential stereochemical information. In the case of a dimer structure of bis(1-aminohexane-1-carboxylato-κ2N,O)copper(II) both the 13C and 2H resolutions were good enough to confirm the presence of the cis and trans forms in the asymmetric unit. With regard to the internal solid-state motions in the crystal lattice, the obtained quadrupolar tensor parameters were similar for the D,L- and L,L-alaninato isomers and also for the cis-trans forms suggesting similar crystal packing effects, static amine deuterons involved in hydrogen bonding, and fast rotating methyl groups. (Graph Presented).

Original languageEnglish
Pages (from-to)4663-4677
Number of pages15
JournalInorganic Chemistry
Volume54
Issue number10
DOIs
Publication statusPublished - May 18 2015

Fingerprint

Magic angle spinning
Stereoisomerism
Alkanes
metal spinning
alkanes
Copper
alanine
Nuclear magnetic resonance
Alanine
solid state
copper
nuclear magnetic resonance
Amines
amines
Propane
Stereochemistry
Deuterium
pentanes
stereochemistry
Hexanes

ASJC Scopus subject areas

  • Inorganic Chemistry
  • Physical and Theoretical Chemistry

Cite this

@article{6467398f834243999ab27a6d762214f0,
title = "Solid-State NMR Study of Paramagnetic Bis(alaninato-κ2N,O)copper(II) and Bis(1-amino(cyclo)alkane-1-carboxylato-κ2N,O)copper(II) Complexes: Reflection of Stereoisomerism and Molecular Mobility in 13C and 2H Fast Magic Angle Spinning Spectra",
abstract = "Solid-state stereochemistry and mobility of paramagnetic copper(II) complexes formed by aliphatic amino acids (L-alanine, D,L-alanine, 1-amino-2-methyl-alanine) and 1-amino(cyclo)alkane-1-carboxylic acids (alkane = propane, butane, pentane, hexane) as bidentate ligands has been studied by 13C and 2H solid-state fast magic angle spinning (MAS) NMR spectroscopy. We examined the prospective method to characterize solid-state paramagnetic compounds in a routine way. Both 13C and 2H MAS spectra can distinguish D,L and L,L diastereomers of natural and polydeuterated bis([Dn]alaninato)copper(II) (n = 0, 2, 8) complexes with axial and/or equatorial methyl positions (conformations) primarily due to different Fermi-contact (FC) contributions. The three-bond hyperfine couplings clearly show Karplus-like dependence on the torsional angles which turned out to be a useful assignment aid. Density functional theory calculations of the FC term and crystal structures were also used to aid the final assignments. The correlations obtained for bis(alaninato-κ2N,O)copper(II) complexes were successfully used to characterize other complexes. The usefulness of the 2H MAS spectra of the deuterated complexes was underlined. Even the spectra of the easily exchangeable amine protons contained essential stereochemical information. In the case of a dimer structure of bis(1-aminohexane-1-carboxylato-κ2N,O)copper(II) both the 13C and 2H resolutions were good enough to confirm the presence of the cis and trans forms in the asymmetric unit. With regard to the internal solid-state motions in the crystal lattice, the obtained quadrupolar tensor parameters were similar for the D,L- and L,L-alaninato isomers and also for the cis-trans forms suggesting similar crystal packing effects, static amine deuterons involved in hydrogen bonding, and fast rotating methyl groups. (Graph Presented).",
author = "G{\'a}bor Szalontai and R{\'o}bert Csonka and G. Speier and J. Kaizer and Jasmina Sabolović",
year = "2015",
month = "5",
day = "18",
doi = "10.1021/ic502987e",
language = "English",
volume = "54",
pages = "4663--4677",
journal = "Inorganic Chemistry",
issn = "0020-1669",
publisher = "American Chemical Society",
number = "10",

}

TY - JOUR

T1 - Solid-State NMR Study of Paramagnetic Bis(alaninato-κ2N,O)copper(II) and Bis(1-amino(cyclo)alkane-1-carboxylato-κ2N,O)copper(II) Complexes

T2 - Reflection of Stereoisomerism and Molecular Mobility in 13C and 2H Fast Magic Angle Spinning Spectra

AU - Szalontai, Gábor

AU - Csonka, Róbert

AU - Speier, G.

AU - Kaizer, J.

AU - Sabolović, Jasmina

PY - 2015/5/18

Y1 - 2015/5/18

N2 - Solid-state stereochemistry and mobility of paramagnetic copper(II) complexes formed by aliphatic amino acids (L-alanine, D,L-alanine, 1-amino-2-methyl-alanine) and 1-amino(cyclo)alkane-1-carboxylic acids (alkane = propane, butane, pentane, hexane) as bidentate ligands has been studied by 13C and 2H solid-state fast magic angle spinning (MAS) NMR spectroscopy. We examined the prospective method to characterize solid-state paramagnetic compounds in a routine way. Both 13C and 2H MAS spectra can distinguish D,L and L,L diastereomers of natural and polydeuterated bis([Dn]alaninato)copper(II) (n = 0, 2, 8) complexes with axial and/or equatorial methyl positions (conformations) primarily due to different Fermi-contact (FC) contributions. The three-bond hyperfine couplings clearly show Karplus-like dependence on the torsional angles which turned out to be a useful assignment aid. Density functional theory calculations of the FC term and crystal structures were also used to aid the final assignments. The correlations obtained for bis(alaninato-κ2N,O)copper(II) complexes were successfully used to characterize other complexes. The usefulness of the 2H MAS spectra of the deuterated complexes was underlined. Even the spectra of the easily exchangeable amine protons contained essential stereochemical information. In the case of a dimer structure of bis(1-aminohexane-1-carboxylato-κ2N,O)copper(II) both the 13C and 2H resolutions were good enough to confirm the presence of the cis and trans forms in the asymmetric unit. With regard to the internal solid-state motions in the crystal lattice, the obtained quadrupolar tensor parameters were similar for the D,L- and L,L-alaninato isomers and also for the cis-trans forms suggesting similar crystal packing effects, static amine deuterons involved in hydrogen bonding, and fast rotating methyl groups. (Graph Presented).

AB - Solid-state stereochemistry and mobility of paramagnetic copper(II) complexes formed by aliphatic amino acids (L-alanine, D,L-alanine, 1-amino-2-methyl-alanine) and 1-amino(cyclo)alkane-1-carboxylic acids (alkane = propane, butane, pentane, hexane) as bidentate ligands has been studied by 13C and 2H solid-state fast magic angle spinning (MAS) NMR spectroscopy. We examined the prospective method to characterize solid-state paramagnetic compounds in a routine way. Both 13C and 2H MAS spectra can distinguish D,L and L,L diastereomers of natural and polydeuterated bis([Dn]alaninato)copper(II) (n = 0, 2, 8) complexes with axial and/or equatorial methyl positions (conformations) primarily due to different Fermi-contact (FC) contributions. The three-bond hyperfine couplings clearly show Karplus-like dependence on the torsional angles which turned out to be a useful assignment aid. Density functional theory calculations of the FC term and crystal structures were also used to aid the final assignments. The correlations obtained for bis(alaninato-κ2N,O)copper(II) complexes were successfully used to characterize other complexes. The usefulness of the 2H MAS spectra of the deuterated complexes was underlined. Even the spectra of the easily exchangeable amine protons contained essential stereochemical information. In the case of a dimer structure of bis(1-aminohexane-1-carboxylato-κ2N,O)copper(II) both the 13C and 2H resolutions were good enough to confirm the presence of the cis and trans forms in the asymmetric unit. With regard to the internal solid-state motions in the crystal lattice, the obtained quadrupolar tensor parameters were similar for the D,L- and L,L-alaninato isomers and also for the cis-trans forms suggesting similar crystal packing effects, static amine deuterons involved in hydrogen bonding, and fast rotating methyl groups. (Graph Presented).

UR - http://www.scopus.com/inward/record.url?scp=84929593866&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84929593866&partnerID=8YFLogxK

U2 - 10.1021/ic502987e

DO - 10.1021/ic502987e

M3 - Article

C2 - 25920900

AN - SCOPUS:84929593866

VL - 54

SP - 4663

EP - 4677

JO - Inorganic Chemistry

JF - Inorganic Chemistry

SN - 0020-1669

IS - 10

ER -