Self-Assembly and Interconversion of Tetranuclear Copper(II) Complexes Katharina Isele Patrick Franz Christina Ambrus Gérald Bernardinelli Silvio Decurtins Alan F. Williams 10.1021/ic0500762.s001 https://acs.figshare.com/articles/dataset/Self_Assembly_and_Interconversion_of_Tetranuclear_Copper_II_Complexes/3284146 The ligand 1,2-bis(benzimidazol-2-yl)-1,2-ethanediol (H<sub>2</sub>bzimed, <b>1</b>) and its N-methylated analogue (H<sub>2</sub>mbzimed<b>, 2</b>) form a variety of polynuclear complexes with copper(II), all of which contain a planar Cu<sub>2</sub>O<sub>2</sub> lozenge as a central element and in which the bridging oxygen belongs to an alkoxo group of the ligand. Syntheses are reported for dinuclear [Cu<sub>2</sub>(Hmbzimed)<sub>2</sub>](ClO<sub>4</sub>)<sub>2</sub>·1.5H<sub>2</sub>O, Cu<sub>2</sub><b>2</b><sub>2</sub>, and the tetranuclear species [Cu<sub>4</sub>(Hbzimed)<sub>4</sub>(ClO<sub>4</sub>)<sub>2</sub>](NO<sub>3</sub>)<sub>2</sub>·4H<sub>2</sub>O, Cu<sub>4</sub><b>1</b><sub>4</sub>, [Cu<sub>4</sub>(Hmbzimed)<sub>2</sub>(mbzimed)Cl<sub>2</sub>](ClO<sub>4</sub>)<sub>2</sub>·2H<sub>2</sub>O·C<sub>2</sub>H<sub>5</sub>OH, Cu<sub>4</sub><b>2</b><sub>3</sub>, and <i>rac</i>-[Cu<sub>4</sub>(H<sub>2</sub>bzimed)<sub>4</sub>(bzimed)(ClO<sub>4</sub>)<sub>2</sub>](ClO<sub>4</sub>)<sub>4</sub>·1.5H<sub>2</sub>O·3.5C<sub>2</sub>H<sub>5</sub>OH, Cu<sub>4</sub><b>1</b><sub>5</sub>. Crystal structures are reported for the tetranuclear species. Cu<sub>4</sub><b>1</b><sub>4</sub> shows a cubane structure, Cu<sub>4</sub><b>2</b><sub>3</sub> a stepped cubane structure, and <i>rac-</i>Cu<sub>4</sub><b>1</b><sub>5</sub> a novel structure in which one doubly deprotonated ligand lies between the two Cu<sub>2</sub>O<sub>2</sub> units. Magnetic susceptibility measurements indicate that all complexes show antiferromagnetic coupling in the solid state. Studies in solution (ESI-MS, CD, NMR) show that Cu<sub>2</sub><b>2</b><sub>2</sub> and Cu<sub>4</sub><b>2</b><sub>3</sub> persist in solution but that Cu<sub>4</sub><b>1</b><sub>4</sub> dissociates partially and <i>rac-</i>Cu<sub>4</sub><b>1</b><sub>5</sub> completely. The six coordination modes of the ligands are discussed together with the effect of the N-methylation on the ligand conformation. 2005-05-30 00:00:00 H 2 bzimed Cu 4 1 5 Cu 4 1 4 NMR OH H 2 mbzimed Cu 4 cubane structure complexes show antiferromagnetic tetranuclear species Cu 2 O 2 lozenge Cu 2 2 2 Cu 4 2 3 Cu 2 O 2 units Magnetic susceptibility measurements