Syntheses, Characterization, and Magneto–Structural Analyses in μ 1,3 ‐Acetato‐Bridged Tetracopper(II) and μ 1,3 ‐ and μ 1,1,3 ‐Acetato‐Bridged Pentanickel(II) Clusters

Two pentanuclear Ni II complexes, [Ni 5 (L 1 ) 2 (CH 3 COO) 6 (OH) 2 (MeOH) 2 ] ( 1 ) and [Ni 5 (L 2 ) 2 (CH 3 COO) 6 (OH) 2 (H 2 O) 2 ] ( 2 ), and one tetranuclear Cu II complex, [Cu 4 (L 3 ) 2 (CH 3 COO) 4 (O)] ( 3 ), have been synthesized from phenol‐based “end‐off” compartmental ligands HL 1 to HL 3 {HL 1 = 2,6‐bis[ethyl(2‐thienyl)iminomethyl]‐4‐ tert ‐butylphenol; HL 2 = 2,6‐bis[ethyl(2‐thienyl)iminomethyl]‐4‐chlorophenol and HL 3 = 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 [Ni 2 L 2 ] units linked to a central Ni ion by bridging μ 3 ‐hydroxo groups. The cluster is stabilized by syn ‐ syn ‐μ 1,3 ‐bridging and μ 1,1,3 ‐bridging acetate anions. The structural analysis of 3 revealed two crystallographically independent complexes that consisted of a tetrahedron of Cu II ions connected to a central μ 4 ‐oxo species and further bridged by four acetate groups along four of the six edges of the Cu 4 core. The other two edges are occupied by μ‐phenoxo bridges from the deprotonated L 3 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 .