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Encapsulation of [Mn(bpy)3] cations in 2D [Mn(dca)3] sheet: Synthesis, X-ray structure and EPR study |
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| Authors: | Dasarath Mal Jean-Pierre Tuchagues |
| Institution: | a Department of Chemistry, Jadavpur University, Kolkata 700 032, India b Laboratoire de Chimie de Coordination du CNRS, UPR 8241, 205 Route de Narbonne, 31077 Toulouse, Cedex 04, France c School of EPS-Chemistry, Heriot-Watt University, Edinburgh, EH14 4AS, UK |
| Abstract: | The reaction of Mn(NO3)2 · 4H2O, 2,2′-bipyridine (bpy) and sodium dicyanamide (dca) in aqueous medium yielded the {Mn(bpy)3]Mn(dca)3]2}n (1). The single-crystal X-ray analysis of 1 revealed that the anionic part of the complex, Mn(dca)3]−, features infinite 2D sheets with a honeycomb-like porous structure having a void space of ca. 12 Å in which Mn(bpy)3]2+ cations are encapsulated to yield a fascinating molecular assembly. MnII ions possess an octahedral geometry both in the anionic and cationic components of complex 1. In the anionic component, each MnII ion is bridged by three pairs of dicyanamide anions in an end-to-end fashion with two other MnII ions from adjacent Mn(dca)3]− moieties. This type of linking propagates parallel to the bc crystallographic plane to form 2D sheets. Mn(bpy)3]2+ is found to have somewhat “squeezed” upon encapsulation. No measurable magnetic interaction was evidenced through variable temperature magnetic susceptibility measurements. However, in addition to the broad g ≈ 2 resonance typical of magnetically diluted Mn(bpy)3]2+ cations, EPR spectroscopy evidenced exchange narrowing of the Mn(dca)3]− resonance at g ≈ 2 thus indicating operation of weak magnetic interactions extended over the whole 2D network through the dca− bridges. |
| Keywords: | Manganese(II) dca complex Crystal structure EPR spectroscopy Two-dimensional structure |
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