A Rare Phenoxido/Acetato/Azido Bridged Trinuclear and an Unprecedented Phenoxido/Azido Bridged One-Dimensional Polynuclear Nickel(II) Complexes: Synthesis, Crystal Structure, and Magnetic Properties with Theoretical Investigations on the Exchange Mechanism

摘要

The reaction of a tridentate Schiff base ligandnHL (2-[(3-dimethylaminopropylimino)-methyl]-phenol) withnNi(II) acetate or perchlorate salts in the presence of azide asncoligand has led to two new Ni(II) complexes of formulasn[Ni3L2(OAc)2(μ1,1-N3)2(H2O)2]·2H2O (1) and [Ni2L2(μ1,1-nN3)(μ1,3-N3)]n(2). Single crystal X-ray structures show thatncomplex 1 is a linear trinuclear Ni(II) compound containing anμ2-phenoxido, an end-on (EO) azido and a syn-syn acetatonbridge between the terminal and the central Ni(II) ions.nComplex 2 can be viewed as a one-dimensional (1D) chain innwhich the triply bridged (di-μ2-phenoxido and EO azido) dimeric Ni2 units are linked to each other in a zigzag pattern by a singlenend-to-end (EE) azido bridge. Variable-temperature magnetic susceptibility studies indicate the presence of moderatenferromagnetic exchange coupling in complex 1 with J value of 16.51(6) cm−1. The magnetic behavior of 2 can be fitted in annalternating ferro- and antiferromagnetic model [JFM = +34.2(2.8) cm−1 and JAF = −21.6(1.1) cm−1] corresponding to the triplenbridged dinuclear core and EE azido bridge respectively. Density functional theory (DFT) calculations were performed toncorroborate the magnetic results of 1 and 2. The contributions of the different bridges toward magnetic interactions in bothncompounds have also been calculated.