Chiral recognition by CD-sensitive dimeric zinc porphyrin host. 2. Structural studies of host - guest complexes with chiral alcohol and monoamine conjugates

T. Kurtán, N. Nesnas, F. E. Koehn, Y. Q. Li, K. Nakanishi, N. Berova

Research output: Contribution to journalArticle

137 Citations (Scopus)

Abstract

A structural study of complexes formed between a dimeric zinc porphyrin tweezer (host) and chiral monoalcohols and monoamines derivatized by a bidentate carrier molecule (guest) confirmed that their CD couplets arise from the preferred porphyrin helicity of 1:1 host-guest complexes. NMR experiments and molecular modeling of selected tweezer complexes revealed that the preferred conformation is the one in which the L (larger) group protrudes from the porphyrin sandwich; this preferred helicity of the complex determines the CD of the complexes. It was found that the porphyrin ring-current induced 1H chemical shifts and molecular modeling studies of the complex lead to the assignments of relative steric size of the L (large)/M (medium) substituents attached to the stereogenic center. The assignments, in turn, are correlated with the sign of the CD exciton couplet that establishes the absolute configuration at the stereogenic center. Variable-temperature NMR experiments proved that the observed increase in CD amplitude at lower temperatures derives from conformational changes in the preferred offset geometry between two porphyrin rings.

Original languageEnglish
Pages (from-to)5974-5982
Number of pages9
JournalJournal of the American Chemical Society
Volume123
Issue number25
DOIs
Publication statusPublished - Oct 3 2001

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

Fingerprint Dive into the research topics of 'Chiral recognition by CD-sensitive dimeric zinc porphyrin host. 2. Structural studies of host - guest complexes with chiral alcohol and monoamine conjugates'. Together they form a unique fingerprint.

  • Cite this