Influence of Axial Ligands on Diverse Properties in Three Trinickel String Complexes

Abstract

Three new trinickel string complexes, [Ni₃(dpa)₄(3-nba)₂](1), [Ni₃(dpa)₄(4-nba)₂]·(CH₃OH) (2), and [Ni₃(dpa)₄(3,5-dnba)₂](3) where dpa⁻ is the anion of 2,2′-dipyridylamine, 3-nba⁻ is 3-nitrobenzoate anion, 4-nba⁻ is 4-nitrobenzoate anion, and 3,5-dnba⁻ is 3,5-dinitrobenzoate anion, were synthesized in good yield and characterized by X-ray crystallography, infrared spectra, elemental analysis, magnetic susceptibility, cyclic voltammogram (CV), UV-vis spectra, fluorescence spectra, and TG analysis. The magnetic susceptibilities suggested that the terminal Ni atoms in all three complexes are in high-spin state while the central Ni atom is in a low-spin state. The CVs of complexes 1–3 showed reversible one-electron redox waves at E_1/2 = 1.1395 V for 1, 1.108 V for 2, and 1.109 V for 3 corresponding to Ni₃ ⁷⁺/Ni₃ ⁶⁺. The Ni-Ni distances in three complexes are somewhat different, indicating the axial nitrobenzoate ligands have significant effect on the structural assembly.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry to view the supplemental file.

Keywords:

• crystal structure
• cyclic voltammetric property
• magnetic property
• metal string complex

Acknowledgments

This work was supported by the Zhejiang Provincial Natural Science Foundation of China (grant No. Z407036), the National Natural Science Foundation of China (grant No. 20573092).