Crystal-driven distortion of ligands in copper coordination complexes

Conformational pseudo-enantiomers

Xiaodong Xu, Kevin J. Maresca, Debasis Das, Steffen Zahn, Jon Zubieta, James Canary

Research output: Contribution to journalArticle

Abstract

The ligand in [Cu(6)CH3CN]- (ClO4)2 adopts two conformations that may be described as "pseudo-enantiomers" in that they possess approximately mirror-image molecular helicity, although they differ in the orientation of a single methyl substituent. The two conformations differ in energy as judged by analogy to other compounds studied previously, computation of the relative free energies of formation of the isomers, and measurement of solution circular dichroism spectra. The solid-state structures of both single enantiomer and racemic forms of the complex were determined by X-ray crystallography. In the chiral complex, a quasi-racemate was observed with both pseudo-enantiomeric conformers present in the asymmetric unit. Packing forces induce a higher energy conformation in order to achieve higher apparent symmetry in the solid state. In contrast, the racemic complex only displayed a single conformation corresponding to the lower energy one of the two observed in the single enantiomer structure.

Original languageEnglish (US)
Pages (from-to)5679-5683
Number of pages5
JournalChemistry - A European Journal
Volume8
Issue number24
DOIs
StatePublished - Dec 16 2002

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Enantiomers
Coordination Complexes
Conformations
Copper
Ligands
Crystals
X ray crystallography
Dichroism
Crystal orientation
Isomers
Free energy
Mirrors

Keywords

  • Chirality
  • Circular dichroism
  • Conformation analysis
  • Copper
  • Solid-state structures

ASJC Scopus subject areas

  • Chemistry(all)

Cite this

Crystal-driven distortion of ligands in copper coordination complexes : Conformational pseudo-enantiomers. / Xu, Xiaodong; Maresca, Kevin J.; Das, Debasis; Zahn, Steffen; Zubieta, Jon; Canary, James.

In: Chemistry - A European Journal, Vol. 8, No. 24, 16.12.2002, p. 5679-5683.

Research output: Contribution to journalArticle

Xu, Xiaodong ; Maresca, Kevin J. ; Das, Debasis ; Zahn, Steffen ; Zubieta, Jon ; Canary, James. / Crystal-driven distortion of ligands in copper coordination complexes : Conformational pseudo-enantiomers. In: Chemistry - A European Journal. 2002 ; Vol. 8, No. 24. pp. 5679-5683.
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