ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Nickel(II) complex with 1,4,7-tris(2-aminoethyl)-1,4,7-triazacyclononane

Masahiro Mikuriya, Mayu Hamagawa, Natsuki Tomioka, Rika Fujimori, Daisuke Yoshioka, Shoichi Hori, Taro Kuriyama, Hiroshi Sakiyama, Makoto Handa, and Ryoji Mitsuhashi

Department of Applied Chemistry for Environment and Research Center for Coordination Molecule-based Devices, School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda 669-1337, Japan

E-mail: junpei@kwansei.ac.jp

Abstract: A nickel(II) complex, [Ni(taetacn)](ClO₄)₂·H₂O, where taetacn = 1,4,7-tris(2-aminoethyl)-1,4,7- triazacyclononane was synthesized. The crystal structure was determined by the single-crystal X-ray diffraction method at 293 K. The complex crystallizes in the orthorhombic space groupPna2₁ with a = 16.004(2) Å, b = 10.186(1) Å, c = 13.937(2) Å, V = 2271.9(5) ų, D_x = 1.56 g cm⁻³, Dm = 1.59 g cm⁻³ (floatation method), and Z = 4. The R₁ [I > 2σ(I)] and wR₂ (all data) values are 0.0636 and 0.1672, respectively, for all 4845 independent reflections. The compound is composed of octahedral nickel(II) cation with three 2-aminoethyl pendant groups of taetacn, tetrahedral ClO− 4 anion, and a water molecule of crystallization. Electronic spectra are consistent with the octahedral geometry. Temperature dependence of the magnetic susceptibility (4.5-300 K) can be interpreted considering the zero-field splitting of the nickel(II) ion (g = 2.14, D = 3.72 cm⁻¹, and Nα = 300 × 10⁻⁶ cm³ mol⁻¹). Cyclic voltammetry in DMF showed quasi-reversible and irreversible oxidation waves (E_pa = 0.54 V, E_pc = 0.45 V; E_pa = 1.16 V, E_pc = 0.71 V vs. Ag/Ag⁺).

Keywords: nickel(II) complex – triazacyclononane ligand – crystal structure – magnetic property – electronic spectra

Full paper is available at www.springerlink.com.

DOI: 10.1515/chempap-2015-0165

Chemical Papers 70 (1) 69–74 (2016)