Synthesis and Magnetic Properties of a Copper Cube: [Cu4(OH)4(C16H18N2)4]4+ (ClO4)4 C3H6O [C16H18N2=(E)‐1,6‐[Di(pyridin‐4‐yl)hex‐3‐ene]

• Published in: ChemistryOpen (Weinheim) Vol. 8; no. 9; pp. 1204 - 1208
• Main Authors: Plater, M. John, Darr, Amara, Crawford, Catriona, Murray, Craig, Simpson, Struan, Harrison, William T. A., Clemente‐Juan, Juan M.
• Format: Journal Article
• Language: English
• Published: Hoboken John Wiley and Sons Inc 01-09-2019; Wiley-VCH
• Subjects: clusters; copper(II) perchlorate; Jahn-Teller distortion; magnetic properties
• ISSN: 2191-1363; 2191-1363
• DOI: 10.1002/open.201900260

The synthesis of a Cu4(OH)4 cube which is coordinated by four molecules of the dipyridyl ligand 1,6‐[di(pyridin‐4‐yl)hex‐3‐ene] is reported. This compound has a trans double bond which restricts the conformational freedom of the ligand and favours coordination within a unique copper cube. The structure was solved by an X‐Ray single crystal structure determination and low temperature magnetic susceptibility measurements examined its magnetic properties. The cube classification corresponds to the type I classification of Mergehenn and Haase and the short/long distribution of Cu ⋅⋅⋅ Cu separations in the cube as defined by Ruiz. The magnetic susceptibility measurements show paramagnetic behaviour down to 50 K but below this the copper cube shows weak ferromagnetic exchange interactions. The low temperature magnetic susceptibility characteristics are examined in detail then modelled and compared to other similar Cu4O4 copper cubes.
Four dipyridyl ligands (1,6‐[di(pyridin‐4‐yl)hex‐3‐ene]) fold and coordinate within a unique Cu4(OH)4 cube which has interesting magnetic properties. The dipyridyl ligand contains a trans double bond which restricts the conformational freedom and favours a unique copper cube because 1,6‐[di(pyridin‐4‐yl)hexane] gives a different extended structure under related conditions.