Magnetic Property and Crystal Structure of Alkoxo-bridged Bi- and Tetranuclear Copper(II) Complexes with Condensation Products of 3-Ethoxymethylene-2,4-pentanedione and Amino Alcohols

Abstract

Abstract Alkoxo-bridged polynuclear copper(II) complexes with condensation products of 3-ethoxymethylene-2,4-pentanedione and each of three amino alcohols, 2-aminoethanol, 3-amino-1-propanol, and 1-amino-2-propanol, were prepared and characterized by elemental analyses, infrared spectra, electronic spectra, molecular weight measurements, magnetic susceptibility measurements, and crystal structure analysis, the complexes being abbreviated as Cu(L-2), Cu(L-3), and Cu(L-2m), respectively. Cu(L-3) is a dimer, but Cu(L-2m) and Cu(L-2) are tetramers. The magnetic susceptibility of violet Cu(L-3), whose electronic spectrum exhibits a d-d band maximum at 17.7×103 cm−1, is in conformity to the Bleaney-Bowers equation with exchange integral −2J=920 cm−1. Cu(L-3) consists of alkoxo-bridged centrosymmetric binuclear units, where the geometries around the copper ion and bridged oxygen atom are planar and the angle of Cu–O–Cu is 103.6(1)°. The magnetisms of blue complexes Cu(L-2) and Cu(L-2m) exhibiting a d-d band maximum at 15.7×103 cm−1 obey the Curie Weiss law with positive Weiss constants 17 and 20 K, respectively, and are in accord with the Heisenberg model based on a tetranuclear cubane-like structure.