Mononuclear or Coordination Polymer Complexes? Both Are Possible for 3,6,9-Trioxaundecanedioic Acid

Area of Science:

• Coordination Chemistry
• Supramolecular Chemistry
• Crystallography

Background:

• Predicting thermodynamically stable supramolecular structures from building blocks is challenging.
• Existing models for structure prediction can be rigid and require adaptation.
• Metallo-supramolecular chemistry offers diverse structural possibilities.

Purpose of the Study:

• To investigate the formation of metallo-supramolecular architectures using 3,6,9-trioxaundecanedioic acid derivatives.
• To elucidate the factors controlling the assembly of discrete versus polymeric structures.
• To understand the role of ligand flexibility and metal coordination in dictating supramolecular organization.

Main Methods:

• Synthesis and crystal structure determination of Mn(II), Co(II), and Zn(II) complexes.
• Analysis of coordination numbers and ligand conformations.
• Comparative study of resulting supramolecular architectures.

Main Results:

• Three distinct metallo-supramolecular architectures were characterized.
• The Mn(II) complex formed a discrete, heptacoordinated structure.
• The Co(II) and Zn(II) complexes assembled into helical polymers.
• Ligand flexibility and the number of coordinating atoms were identified as key determinants.

Conclusions:

• The interplay between ligand spacer flexibility and metal coordination number governs the divergent or convergent assembly of coordination architectures.
• This provides insight into controlling supramolecular structure formation.
• The findings contribute to the rational design of novel coordination polymers and discrete complexes.