Nickel complexes with tris(2-aminoethyl)amine (tren): [Ni3(tren)4(H2O)2][Cr(ox)3]2·6H2O (ox = oxalate), {[Ni2(tren)3][ClO4]4·H2O}n, and [Ni2(tren)2(aepd)][ClO4]4·2H2O (aepd = N-(2-aminoethyl)pyrrolidine-3,4-diamine). Synthesis, structure and magnetism †

Abstract

Nickel complexes with tris(2-aminoethyl)amine (tren): [Ni 3 (tren) 4 (H 2 O) 2 ][Cr(ox)3 ] 2 ؒ6H 2 O (ox ‫؍‬ oxalate), {[Ni 2 (tren) 3 ][ClO 4 ] 4 ؒH 2 O} n , and [Ni 2 (tren) 2 (aepd)][ClO 4 ] 4 ؒ2H 2 O (aepd ‫؍‬ N-(2-aminoethyl)pyrrolidine-3,4-diamine). Synthesis, structure and magnetism † Reaction of K 3 [Cr(ox) 3 ] (ox = oxalate) with nickel() and tris(2-aminoethyl)amine (tren) in aqueous solution resulted in isolation of the bimetallic assembly [Ni 3 (tren) 4 (H 2 O) 2 ][Cr(ox) 3 ] 2 ؒ6H 2 O. The polymeric complex {[Ni 2 (tren) 3 ]-[ClO 4 ] 4 ؒH 2 O} n has been prepared by reaction of nickel() perchlorate and tren in aqueous solution. From the same reaction mixture the complex [Ni 2 (tren) 2 (aepd)][ClO 4 ] 4 ؒ2H 2in which a bridging tren ligand contains a carbon-carbon bond between two arms forming a substituted pyrrolidine, has been isolated. The complexes have been characterized by X-ray crystallography. The magnetic susceptibility (300-4.2 K) and magnetization data (2, 4 K, H = 0-5 T) for {[Ni 2 (tren) 3 ][ClO 4 ] 4 ؒH 2 O} n (300 K , 4.23 µ B ) exhibit evidence of weak antiferromagnetic coupling and zero field splitting (2J = Ϫ1.8 cm Ϫ1 ; |D| = 2 cm Ϫ1 ) at low temperature. For [Ni 3 (tren) 4 (H 2 O) 2 ][Cr(ox) 3 ] 2 ؒ6H 2 O the susceptibility data at 300 K are indicative of uncoupled nickel() and chromium() sites with zero-field splitting and intramolecular antiferromagnetic coupling predicted at low temperature.

Structure, Spectra, and DFT Simulation of Nickel Benzazolate Complexes with Tris(2-aminoethyl)amine Ligand

“…The oxygen atom of the benzazolate (O1) is in an equatorial position. The Ni–N tren bond distances (2.102–2.162 Å) are within the range reported for complexes containing the [Ni­(tren)] moiety. − The Ni–N1 bond distances are 2.063, 2.087, 2.099 Å for complexes 1 , 2 , and 3 , respectively. The bond distances Ni–O1 are 2.093, 2.034, and 2.071 Å for 1 , 2 , and 3 , respectively.…”