Impact of the substitution pattern of xylyl-bridged 1,4-bis(1,4,7-triazacyclononane) ligands on the crystal structures of their zinc(II) complexes and their ability to bind to N-terminally tagged proteins

Campbell J. Coghlan, Eva M. Campi, Stuart R. Batten, W. Roy Jackson, Milton T.W. Hearn

Research output: Contribution to journalArticleResearchpeer-review

1 Citation (Scopus)

Abstract

Reactions of ortho-, para- and substituted meta-xylenyl bridged bis(tacn) ligands with two or three molar equivalents of Zn(NO3)2·6H2O at pH 5.0 in the presence of NaClO4 or NH4PF6 resulted in the formation of a range of crystalline zinc complexes. In the presence of perchlorate counter ions the Lpx and Lphx ligands gave rise to dinuclear Zn2+ coordination complexes [Zn2Cl2(Lpx)(H2O)2](ClO4)2(H2O) and [Zn2Cl2(Lphx)(H2O)2](ClO4)2(H2O)2 respectively, which formed infinite 1D polymeric chains. In contrast, in the presence of the hexafluorophosphate counter ion, the Lnix ligand formed a unique tetranuclear Zn2+ complex, [Zn2Cl2(Lnix)(H2O)3](Cl)(PF6)2(H2O)4, the Lcax ligand formed an octanuclear complex [Zn8Cl4(Lcax)4(H2O)10](PF6)6.7(NO3)1.3(H2O)3.3, whilst the Lox ligand formed a mononuclear sandwich structure, [Zn(Lox)](PF6)2(H2O). The protonated metal-free Lpx ligand crystallised as [H4(Lpx)](NO3)2(PF6)(H2O)2 with the stacked ligand cations forming a hydrogen-bonded network. These structural attributes provide an explanation for the significant differences in binding behaviour of recombinant N-terminally tagged proteins with the corresponding Zn2+-azamacrocyclic complexes, compared to the analogous Cu2+- or Ni2+-azamacrocyclic complexes, when immobilised onto support materials and used as immobilised metal affinity chromatographic (IMAC) adsorbents.

Original languageEnglish
Pages (from-to)187-197
Number of pages11
JournalPolyhedron
Volume144
DOIs
Publication statusPublished - 1 Apr 2018

Keywords

  • Bis(tacn) ligands
  • Crystal structures
  • IMAC separations
  • Xylenyl linkers
  • Zinc(II) aza-macrocyclic complexes

Cite this

@article{ff3e92c9ef7f4d26b4fc4dc9d16788b8,
title = "Impact of the substitution pattern of xylyl-bridged 1,4-bis(1,4,7-triazacyclononane) ligands on the crystal structures of their zinc(II) complexes and their ability to bind to N-terminally tagged proteins",
abstract = "Reactions of ortho-, para- and substituted meta-xylenyl bridged bis(tacn) ligands with two or three molar equivalents of Zn(NO3)2·6H2O at pH 5.0 in the presence of NaClO4 or NH4PF6 resulted in the formation of a range of crystalline zinc complexes. In the presence of perchlorate counter ions the Lpx and Lphx ligands gave rise to dinuclear Zn2+ coordination complexes [Zn2Cl2(Lpx)(H2O)2](ClO4)2(H2O) and [Zn2Cl2(Lphx)(H2O)2](ClO4)2(H2O)2 respectively, which formed infinite 1D polymeric chains. In contrast, in the presence of the hexafluorophosphate counter ion, the Lnix ligand formed a unique tetranuclear Zn2+ complex, [Zn2Cl2(Lnix)(H2O)3](Cl)(PF6)2(H2O)4, the Lcax ligand formed an octanuclear complex [Zn8Cl4(Lcax)4(H2O)10](PF6)6.7(NO3)1.3(H2O)3.3, whilst the Lox ligand formed a mononuclear sandwich structure, [Zn(Lox)](PF6)2(H2O). The protonated metal-free Lpx ligand crystallised as [H4(Lpx)](NO3)2(PF6)(H2O)2 with the stacked ligand cations forming a hydrogen-bonded network. These structural attributes provide an explanation for the significant differences in binding behaviour of recombinant N-terminally tagged proteins with the corresponding Zn2+-azamacrocyclic complexes, compared to the analogous Cu2+- or Ni2+-azamacrocyclic complexes, when immobilised onto support materials and used as immobilised metal affinity chromatographic (IMAC) adsorbents.",
keywords = "Bis(tacn) ligands, Crystal structures, IMAC separations, Xylenyl linkers, Zinc(II) aza-macrocyclic complexes",
author = "Coghlan, {Campbell J.} and Campi, {Eva M.} and Batten, {Stuart R.} and Jackson, {W. Roy} and Hearn, {Milton T.W.}",
year = "2018",
month = "4",
day = "1",
doi = "10.1016/j.poly.2018.01.013",
language = "English",
volume = "144",
pages = "187--197",
journal = "Polyhedron",
issn = "0277-5387",
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}

Impact of the substitution pattern of xylyl-bridged 1,4-bis(1,4,7-triazacyclononane) ligands on the crystal structures of their zinc(II) complexes and their ability to bind to N-terminally tagged proteins. / Coghlan, Campbell J.; Campi, Eva M.; Batten, Stuart R.; Jackson, W. Roy; Hearn, Milton T.W.

In: Polyhedron, Vol. 144, 01.04.2018, p. 187-197.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Impact of the substitution pattern of xylyl-bridged 1,4-bis(1,4,7-triazacyclononane) ligands on the crystal structures of their zinc(II) complexes and their ability to bind to N-terminally tagged proteins

AU - Coghlan, Campbell J.

AU - Campi, Eva M.

AU - Batten, Stuart R.

AU - Jackson, W. Roy

AU - Hearn, Milton T.W.

PY - 2018/4/1

Y1 - 2018/4/1

N2 - Reactions of ortho-, para- and substituted meta-xylenyl bridged bis(tacn) ligands with two or three molar equivalents of Zn(NO3)2·6H2O at pH 5.0 in the presence of NaClO4 or NH4PF6 resulted in the formation of a range of crystalline zinc complexes. In the presence of perchlorate counter ions the Lpx and Lphx ligands gave rise to dinuclear Zn2+ coordination complexes [Zn2Cl2(Lpx)(H2O)2](ClO4)2(H2O) and [Zn2Cl2(Lphx)(H2O)2](ClO4)2(H2O)2 respectively, which formed infinite 1D polymeric chains. In contrast, in the presence of the hexafluorophosphate counter ion, the Lnix ligand formed a unique tetranuclear Zn2+ complex, [Zn2Cl2(Lnix)(H2O)3](Cl)(PF6)2(H2O)4, the Lcax ligand formed an octanuclear complex [Zn8Cl4(Lcax)4(H2O)10](PF6)6.7(NO3)1.3(H2O)3.3, whilst the Lox ligand formed a mononuclear sandwich structure, [Zn(Lox)](PF6)2(H2O). The protonated metal-free Lpx ligand crystallised as [H4(Lpx)](NO3)2(PF6)(H2O)2 with the stacked ligand cations forming a hydrogen-bonded network. These structural attributes provide an explanation for the significant differences in binding behaviour of recombinant N-terminally tagged proteins with the corresponding Zn2+-azamacrocyclic complexes, compared to the analogous Cu2+- or Ni2+-azamacrocyclic complexes, when immobilised onto support materials and used as immobilised metal affinity chromatographic (IMAC) adsorbents.

AB - Reactions of ortho-, para- and substituted meta-xylenyl bridged bis(tacn) ligands with two or three molar equivalents of Zn(NO3)2·6H2O at pH 5.0 in the presence of NaClO4 or NH4PF6 resulted in the formation of a range of crystalline zinc complexes. In the presence of perchlorate counter ions the Lpx and Lphx ligands gave rise to dinuclear Zn2+ coordination complexes [Zn2Cl2(Lpx)(H2O)2](ClO4)2(H2O) and [Zn2Cl2(Lphx)(H2O)2](ClO4)2(H2O)2 respectively, which formed infinite 1D polymeric chains. In contrast, in the presence of the hexafluorophosphate counter ion, the Lnix ligand formed a unique tetranuclear Zn2+ complex, [Zn2Cl2(Lnix)(H2O)3](Cl)(PF6)2(H2O)4, the Lcax ligand formed an octanuclear complex [Zn8Cl4(Lcax)4(H2O)10](PF6)6.7(NO3)1.3(H2O)3.3, whilst the Lox ligand formed a mononuclear sandwich structure, [Zn(Lox)](PF6)2(H2O). The protonated metal-free Lpx ligand crystallised as [H4(Lpx)](NO3)2(PF6)(H2O)2 with the stacked ligand cations forming a hydrogen-bonded network. These structural attributes provide an explanation for the significant differences in binding behaviour of recombinant N-terminally tagged proteins with the corresponding Zn2+-azamacrocyclic complexes, compared to the analogous Cu2+- or Ni2+-azamacrocyclic complexes, when immobilised onto support materials and used as immobilised metal affinity chromatographic (IMAC) adsorbents.

KW - Bis(tacn) ligands

KW - Crystal structures

KW - IMAC separations

KW - Xylenyl linkers

KW - Zinc(II) aza-macrocyclic complexes

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U2 - 10.1016/j.poly.2018.01.013

DO - 10.1016/j.poly.2018.01.013

M3 - Article

VL - 144

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EP - 197

JO - Polyhedron

JF - Polyhedron

SN - 0277-5387

ER -