Homo- and heteropolynuclear helicates with a '2 + 3 + 2'-dentate compartmental ligand

S.P. Argent, H. Adams, L.P. Harding, T. Riis-Johannessen, J.C. Jeffery, M.D. Ward

Research output: Contribution to journalArticle

43 Citations (Scopus)

Abstract

An octadentate ligand L has been prepared which contains a sequence of bidentate (pyrazolyl-pyridine), terdentate [bis(pyrazolyl)pyridine] and bidentate (pyrazolyl-pyridine) binding sites separated by p-xylyl spacers. This forms a range of double helical complexes in which the two ligands define 4-, 6-, and 4-coordinate binding sites, and there is substantial π-stacking between overlapping parallel areas of the ligands. In [Cu3L2][PF6]4 the sequence of oxidation states for the copper ions is +1, +2, +1 with the Cu(I) ions being four-coordinate at the terminal sites and Cu(II) being in the central six-coordinate site. In [Cu3(OAc)2L2][PF6]4 all copper centres are in oxidation state +2, with the terminal ions having an additional monodentate acetate ligand giving them a five-coordinate geometry. The 4 + 6 + 4 arrangement of coordination numbers means that reaction of L with a mixture of Fe(II) and Ag(I) results in high yield formation of [Ag2FeL2][BF4]4 in which Ag(I) ions occupy the terminal 4-coordinate sites and Fe(II) occupies the central pseudo-octahedral site. Reaction of L with Ag(I) produced a mixture of [Ag3L2][BF4]3 (major product) and [Ag4L2][BF4]4 (minor product). In [Ag3L2][BF4]3 the central Ag(I) ion is, unusually, in a pseudo-octahedral coordination environment from the two meridional, terdentate bis(pyrazolyl)pyridine donors. In [Ag4L2][BF4]4 in contrast the central 6-coordinate cavity is occupied by two Ag(I) ions separated by 2.85 Å. The terdentate chelating bis(pyrazolyl)pyridine units at the centre of the helicate are now substantially twisted such that each donates a bidentate pyrazolyl-pyridine to one Ag(I) centre and a monodentate pyrazole unit to the other. In solution, 1H NMR and mass spectroscopic evidence indicates that the fourth Ag(I) ion is lost and [Ag3L2][BF4]3 forms, unless a large excess of Ag(I) is present in which case traces of [Ag4L2][BF4]4 can be detected by mass spectrometry
LanguageEnglish
Pages904-911
Number of pages8
JournalNew Journal of Chemistry
Volume29
Issue number7
DOIs
Publication statusPublished - 18 May 2005

Fingerprint

Pyridine
Ligands
Ions
Binding sites
Copper
Binding Sites
Oxidation
Chelation
Mass spectrometry
pyridine
Acetates
Nuclear magnetic resonance
Geometry

Cite this

Argent, S. P., Adams, H., Harding, L. P., Riis-Johannessen, T., Jeffery, J. C., & Ward, M. D. (2005). Homo- and heteropolynuclear helicates with a '2 + 3 + 2'-dentate compartmental ligand. New Journal of Chemistry, 29(7), 904-911. https://doi.org/10.1039/b502423d
Argent, S.P. ; Adams, H. ; Harding, L.P. ; Riis-Johannessen, T. ; Jeffery, J.C. ; Ward, M.D. / Homo- and heteropolynuclear helicates with a '2 + 3 + 2'-dentate compartmental ligand. In: New Journal of Chemistry. 2005 ; Vol. 29, No. 7. pp. 904-911.
@article{c614c21c747747cab548f2c034ecaf5c,
title = "Homo- and heteropolynuclear helicates with a '2 + 3 + 2'-dentate compartmental ligand",
abstract = "An octadentate ligand L has been prepared which contains a sequence of bidentate (pyrazolyl-pyridine), terdentate [bis(pyrazolyl)pyridine] and bidentate (pyrazolyl-pyridine) binding sites separated by p-xylyl spacers. This forms a range of double helical complexes in which the two ligands define 4-, 6-, and 4-coordinate binding sites, and there is substantial π-stacking between overlapping parallel areas of the ligands. In [Cu3L2][PF6]4 the sequence of oxidation states for the copper ions is +1, +2, +1 with the Cu(I) ions being four-coordinate at the terminal sites and Cu(II) being in the central six-coordinate site. In [Cu3(OAc)2L2][PF6]4 all copper centres are in oxidation state +2, with the terminal ions having an additional monodentate acetate ligand giving them a five-coordinate geometry. The 4 + 6 + 4 arrangement of coordination numbers means that reaction of L with a mixture of Fe(II) and Ag(I) results in high yield formation of [Ag2FeL2][BF4]4 in which Ag(I) ions occupy the terminal 4-coordinate sites and Fe(II) occupies the central pseudo-octahedral site. Reaction of L with Ag(I) produced a mixture of [Ag3L2][BF4]3 (major product) and [Ag4L2][BF4]4 (minor product). In [Ag3L2][BF4]3 the central Ag(I) ion is, unusually, in a pseudo-octahedral coordination environment from the two meridional, terdentate bis(pyrazolyl)pyridine donors. In [Ag4L2][BF4]4 in contrast the central 6-coordinate cavity is occupied by two Ag(I) ions separated by 2.85 {\AA}. The terdentate chelating bis(pyrazolyl)pyridine units at the centre of the helicate are now substantially twisted such that each donates a bidentate pyrazolyl-pyridine to one Ag(I) centre and a monodentate pyrazole unit to the other. In solution, 1H NMR and mass spectroscopic evidence indicates that the fourth Ag(I) ion is lost and [Ag3L2][BF4]3 forms, unless a large excess of Ag(I) is present in which case traces of [Ag4L2][BF4]4 can be detected by mass spectrometry",
author = "S.P. Argent and H. Adams and L.P. Harding and T. Riis-Johannessen and J.C. Jeffery and M.D. Ward",
note = "cited By 40",
year = "2005",
month = "5",
day = "18",
doi = "10.1039/b502423d",
language = "English",
volume = "29",
pages = "904--911",
journal = "New Journal of Chemistry",
issn = "1144-0546",
publisher = "Royal Society of Chemistry",
number = "7",

}

Argent, SP, Adams, H, Harding, LP, Riis-Johannessen, T, Jeffery, JC & Ward, MD 2005, 'Homo- and heteropolynuclear helicates with a '2 + 3 + 2'-dentate compartmental ligand', New Journal of Chemistry, vol. 29, no. 7, pp. 904-911. https://doi.org/10.1039/b502423d

Homo- and heteropolynuclear helicates with a '2 + 3 + 2'-dentate compartmental ligand. / Argent, S.P.; Adams, H.; Harding, L.P.; Riis-Johannessen, T.; Jeffery, J.C.; Ward, M.D.

In: New Journal of Chemistry, Vol. 29, No. 7, 18.05.2005, p. 904-911.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Homo- and heteropolynuclear helicates with a '2 + 3 + 2'-dentate compartmental ligand

AU - Argent, S.P.

AU - Adams, H.

AU - Harding, L.P.

AU - Riis-Johannessen, T.

AU - Jeffery, J.C.

AU - Ward, M.D.

N1 - cited By 40

PY - 2005/5/18

Y1 - 2005/5/18

N2 - An octadentate ligand L has been prepared which contains a sequence of bidentate (pyrazolyl-pyridine), terdentate [bis(pyrazolyl)pyridine] and bidentate (pyrazolyl-pyridine) binding sites separated by p-xylyl spacers. This forms a range of double helical complexes in which the two ligands define 4-, 6-, and 4-coordinate binding sites, and there is substantial π-stacking between overlapping parallel areas of the ligands. In [Cu3L2][PF6]4 the sequence of oxidation states for the copper ions is +1, +2, +1 with the Cu(I) ions being four-coordinate at the terminal sites and Cu(II) being in the central six-coordinate site. In [Cu3(OAc)2L2][PF6]4 all copper centres are in oxidation state +2, with the terminal ions having an additional monodentate acetate ligand giving them a five-coordinate geometry. The 4 + 6 + 4 arrangement of coordination numbers means that reaction of L with a mixture of Fe(II) and Ag(I) results in high yield formation of [Ag2FeL2][BF4]4 in which Ag(I) ions occupy the terminal 4-coordinate sites and Fe(II) occupies the central pseudo-octahedral site. Reaction of L with Ag(I) produced a mixture of [Ag3L2][BF4]3 (major product) and [Ag4L2][BF4]4 (minor product). In [Ag3L2][BF4]3 the central Ag(I) ion is, unusually, in a pseudo-octahedral coordination environment from the two meridional, terdentate bis(pyrazolyl)pyridine donors. In [Ag4L2][BF4]4 in contrast the central 6-coordinate cavity is occupied by two Ag(I) ions separated by 2.85 Å. The terdentate chelating bis(pyrazolyl)pyridine units at the centre of the helicate are now substantially twisted such that each donates a bidentate pyrazolyl-pyridine to one Ag(I) centre and a monodentate pyrazole unit to the other. In solution, 1H NMR and mass spectroscopic evidence indicates that the fourth Ag(I) ion is lost and [Ag3L2][BF4]3 forms, unless a large excess of Ag(I) is present in which case traces of [Ag4L2][BF4]4 can be detected by mass spectrometry

AB - An octadentate ligand L has been prepared which contains a sequence of bidentate (pyrazolyl-pyridine), terdentate [bis(pyrazolyl)pyridine] and bidentate (pyrazolyl-pyridine) binding sites separated by p-xylyl spacers. This forms a range of double helical complexes in which the two ligands define 4-, 6-, and 4-coordinate binding sites, and there is substantial π-stacking between overlapping parallel areas of the ligands. In [Cu3L2][PF6]4 the sequence of oxidation states for the copper ions is +1, +2, +1 with the Cu(I) ions being four-coordinate at the terminal sites and Cu(II) being in the central six-coordinate site. In [Cu3(OAc)2L2][PF6]4 all copper centres are in oxidation state +2, with the terminal ions having an additional monodentate acetate ligand giving them a five-coordinate geometry. The 4 + 6 + 4 arrangement of coordination numbers means that reaction of L with a mixture of Fe(II) and Ag(I) results in high yield formation of [Ag2FeL2][BF4]4 in which Ag(I) ions occupy the terminal 4-coordinate sites and Fe(II) occupies the central pseudo-octahedral site. Reaction of L with Ag(I) produced a mixture of [Ag3L2][BF4]3 (major product) and [Ag4L2][BF4]4 (minor product). In [Ag3L2][BF4]3 the central Ag(I) ion is, unusually, in a pseudo-octahedral coordination environment from the two meridional, terdentate bis(pyrazolyl)pyridine donors. In [Ag4L2][BF4]4 in contrast the central 6-coordinate cavity is occupied by two Ag(I) ions separated by 2.85 Å. The terdentate chelating bis(pyrazolyl)pyridine units at the centre of the helicate are now substantially twisted such that each donates a bidentate pyrazolyl-pyridine to one Ag(I) centre and a monodentate pyrazole unit to the other. In solution, 1H NMR and mass spectroscopic evidence indicates that the fourth Ag(I) ion is lost and [Ag3L2][BF4]3 forms, unless a large excess of Ag(I) is present in which case traces of [Ag4L2][BF4]4 can be detected by mass spectrometry

U2 - 10.1039/b502423d

DO - 10.1039/b502423d

M3 - Article

VL - 29

SP - 904

EP - 911

JO - New Journal of Chemistry

T2 - New Journal of Chemistry

JF - New Journal of Chemistry

SN - 1144-0546

IS - 7

ER -