Structural and NMR investigations of the ternary adducts of twenty α-amino acids and selected dipeptides with a chiral, diaqua-ytterbium complex

Dickins, R.S.; Batsanov, A.S.; Howard, J.A.K.; Parker, D.; Puschmann, H.; Salamano, S.

Abstract

A detailed investigation of the nature of the binding of each of the 20 common alpha-amino acids and various selected dipeptides to a chiral, diaqua-ytterbium complex in aqueous solution has been carried out. Analysis of the dipolar H-1 NMR paramagnetic shifts suggests that the alpha-amino acids form a common chelated structure within a nine-coordinate mono-capped square antiprismatic coordination environment, with the amine N axially disposed. Crystal structures of nine chelated YbL1-amino acid adducts (Gly, Ala, Ser, Thr, Met) confirm this. The ternary complexes with dipeptides (e.g. Gly-Ala, Gly-Ser, Gly-Met, Gly-Asp, Gly-Asn, Gly-His, Ser-Met, Asp-Phe, His-Gly) also favour the terminal amine as the axial donor with the proximate amide group binding to generate a five-ring chelate. Evidence for chelation through side-chain functionality was found only in the case of N-terminal Asp. The chiral environment about the ytterbium ion upon amino acid binding has also been probed using near-IR circular dichroism spectroscopy.

Citation

Dickins, R., Batsanov, A., Howard, J., Parker, D., Puschmann, H., & Salamano, S. (2004). Structural and NMR investigations of the ternary adducts of twenty α-amino acids and selected dipeptides with a chiral, diaqua-ytterbium complex. Dalton Transactions, 2004(1), 70-80. https://doi.org/10.1039/b311791j

• Journal Article Type: Article
• Acceptance Date: Oct 31, 2003
• Online Publication Date: Nov 27, 2003
• Publication Date: 2004
• Deposit Date: May 15, 2007
• Journal: Dalton Transactions
• Print ISSN: 1477-9226
• Electronic ISSN: 1477-9234
• Publisher: Royal Society of Chemistry
• Peer Reviewed: Peer Reviewed
• Volume: 2004
• Issue: 1
• Pages: 70-80
• DOI: https://doi.org/10.1039/b311791j
• Public URL: https://durham-repository.worktribe.com/output/1602821