Structural Characterization and Magnetic Behaviour of the Ferro-Antiferromagnetic Alternating Manganese–Azido Chain [Mn(3-Et,4-Mepy)2(μ-N3)2]n (3-Et,4-Mepy = 3-Ethyl-4-methylpyridine)

Abstract

The ligands 3-ethyl-4-methylpyridine (3-Et,4-Mepy) and azide coordinate to MnII forming an alternating chain with the formula [Mn(3-Et,4-Mepy)2(μ-N3)2]n. This compound crystallizes in the space group P–1. The compound consists of chains of octahedrally coordinated manganese atoms alternately bridged by double end-to-end (μ1,3) and double end-on (μ1,1) azido bridges, which results in a structurally and magnetically alternating chain. The 3-ethyl-4-methylpyridine ligands are arranged trans, completing the six-fold coordination spheres of the manganese atoms. The Mn–Mn distances are distinctly different: Mn(1)–Mn(1A) = 5.149(3) Å (double end-to-end azido bridge) and Mn(1)–Mn(1B) = 3.402(2) Å (double end-on azido bridge). The magnetic properties of the compound, as studied in the temperature range 300-4 K, show bulk antiferromagnetic interaction. Fitting of the magnetic data by using an equation for alternating ferro-antiferromagnetic S = 5/2 1-D systems gives the parameters JAF = –13.7(1) cm−1, JF = 2.4(1) cm−1, g = 2.036(2).