Cover Picture: Improvement of Energy Capacity with Vitamin C Treated Dual‐Layered Graphene–Sulfur Cathodes in Lithium–Sulfur Batteries (ChemSusChem 17/2015)

Abstract

Two pentanuclear NiII complexes, [Ni5(L1)2(CH3COO)6(OH)2(MeOH)2] (1) and [Ni5(L2)2(CH3COO)6(OH)2(H2O)2] (2), and one tetranuclear CuII complex, [Cu4(L3)2(CH3COO)4(O)] (3), have been synthesized from phenol‐based “end‐off” compartmental ligands HL1 to HL3 {HL1 = 2,6‐bis[ethyl(2‐thienyl)iminomethyl]‐4‐tert‐butylphenol; HL2 = 2,6‐bis[ethyl(2‐thienyl)iminomethyl]‐4‐chlorophenol and HL3 = 2,6‐bis[ethyl(2‐thienyl)iminomethyl]‐4‐methylphenol, respectively}. The complexes have been structurally characterized and their magnetic properties have been investigated within the temperature range 2.2–300 K. Complexes 1 and 2 comprise two dinuclear [Ni2L2] units linked to a central Ni ion by bridging μ3‐hydroxo groups. The cluster is stabilized by syn‐syn‐μ1,3‐bridging and μ1,1,3‐bridging acetate anions. The structural analysis of 3 revealed two crystallographically independent complexes that consisted of a tetrahedron of CuII ions connected to a central μ4‐oxo species and further bridged by four acetate groups along four of the six edges of the Cu4 core. The other two edges are occupied by μ‐phenoxo bridges from the deprotonated L3 ligand. Magnetic investigations revealed both ferromagnetic and antiferromagnetic interactions in 1 and 2 with single‐ion zero‐field splitting of magnitude comparable to exchange interactions, and strong antiferromagnetic interactions in 3.