Interactions Of Aromatic Rings Research Articles

Spectroscopic and magnetic resonance studies on Ni(II), Cu(II) and Pd(II) complexes with Gly-Leu-Tyr and Tyr-Gly-Gly tripeptides

Abstract The structure of tetragonal Ni(II), Cu(II) and Pd(II) complexes with Tyr-Gly-Gly and Gly-Leu-Tyr has been established by absorption spectroscopy, NMR and EPR methods. The aromatic ring interaction with the metal ion has been proposed and it was found to be most effective for Ni(II). In Cu(II) Gly-Leu-Tyr solution the dimer formation occurs at pH 8–10 and the dimer suffers decomposition at pH above 12. In the complexes with all three metal ions the ligands act as tetradentate at pH up to 11 and as tridentate in higher pH regions.

Nuclear magnetic resonance studies of lysine-vasopressin: structural constraints.

The 220-MHz proton NMR spectra of lysine-vasopressin and some related compounds are examined in deuterated dimethyl sulfoxide to obtain structural information that must be satisfied by any proposed conformation of the molecule. This structural information is in the form of dihedral angles (for rotation about the NH-C(alpha)H bonds) from coupling constants, possible hydrogen bonding of the CONH(2) and backbone amide groups from the temperature-dependence of the chemical shift, and aromatic ring-aromatic ring interaction from the effect of the magnetically anisotropic groups on the chemical shift.