Synthesis and characterization of two piperazine containing macrocycles and their transition metal complexes

J Inorg Biochem. 2023 Apr:241:112124. doi: 10.1016/j.jinorgbio.2023.112124. Epub 2023 Jan 9.

Abstract

Rigidification of the ligand scaffolds has been a particular mechanism of interest employed to achieve properties suitable for MRI contrast, catalysis, or other applications of metal complexes. Towards the goal of targeting a 15-anePyN5Pip type ligand, a serendipitous isolation of a 30-anePy2N10Pip2 aza-macrocycle was achieved, instead. X-ray diffraction and determination of pKa events were carried out and compared to 17-anePyN5Pip. Furthermore, the X-ray diffraction of the Cu(II) and Zn(II) complexes of 17-anePyN5Pip was achieved and compared to previous reports of other first-row transition metal derivatives of this ligand. Determination of the log β with both 30-anePy2N10Pip2 and 17-anePyN5Pip with the divalent MnZn metal-ion series was used to demonstrate the impact that the piperazine ring plays compared to other, less rigid macrocycles reported to date.

Keywords: Log B; Macrocycle; Manganese; Piperazine; Pyridinophane.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Coordination Complexes*
  • Ligands
  • Molecular Structure
  • Piperazine
  • Transition Elements*

Substances

  • Coordination Complexes
  • Piperazine
  • Ligands
  • Transition Elements