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Crystal structures of two dimeric nickel di-phenyl-acetate com-plexes
A A Nikiforov1,2, D O Blinou1, E N Dubrov1
1St Petersburg State Institute of Technology, Moskovsky pr. 26, 190013 St Petersburg, Russian Federation.
Acta Crystallographica. Section E, Crystallographic Communications
|November 12, 2019
Summary
The crystal structures of two nickel(II) compounds reveal that bulky dip-henyl-acetate ligands do not hinder the formation of aqua-bridged dimeric cores. These complexes exhibit stabilization through various hydrogen bonds and aromatic interactions.
Area of Science:
- Coordination Chemistry
- Crystal Engineering
- Supramolecular Chemistry
Background:
- Nickel(II) complexes with carboxylate ligands are of interest due to their diverse structural motifs and potential applications.
- The role of sterically demanding ligands in dictating the assembly of metal-organic frameworks and coordination polymers is an active area of research.
- Understanding non-covalent interactions is crucial for designing predictable crystal structures.
Purpose of the Study:
- To elucidate the crystal structures of two novel nickel(II) compounds featuring dip-henyl-acetate ligands.
- To investigate the influence of sterically bulky dip-henyl-acetate and chelating 2,2'-bi-pyridine ligands on the formation of aqua-bridged dimeric nickel(II) cores.
- To identify and analyze the stabilizing intra- and inter-molecular interactions within the crystal lattices.
Main Methods:
- Single-crystal X-ray diffraction was employed to determine the three-dimensional structures of the title compounds.
- Analysis of hydrogen bonding (including O-H···O, N-H···O, C-H···O), C-H···π, and π-π stacking interactions was performed.
- The coordination environment around the nickel(II) centers and the bridging modes of the ligands were examined.
Main Results:
- The crystal structures of two nickel(II) complexes, [Ni2(dip-henyl-acetato)4(pyridine)4(H2O)] (1) and [Ni2(dip-henyl-acetato)4(2,2'-bi-pyridine)2(H2O)]·2.5CH3CN·dip-henyl-acetic acid (2), were successfully determined.
- Both compounds feature a μ-aqua-bridged dimeric nickel(II) core, demonstrating the robustness of this motif.
- The dip-henyl-acetate ligand, despite its steric bulk, effectively coordinates to the nickel centers, and various non-covalent interactions stabilize the overall crystal packing.
Conclusions:
- The formation of the aqua-bridged dimeric nickel(II) core is achievable even with sterically hindered dip-henyl-acetate ligands.
- The presence of pyridine and 2,2'-bi-pyridine ligands, along with dip-henyl-acetate, leads to complex supramolecular assemblies stabilized by hydrogen bonding and π-π interactions.
- These findings contribute to the understanding of structural diversity in nickel(II) coordination compounds and the role of ligand design in crystal engineering.
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