A dimeric tetranuclear copper(II) compound assembled through pentacoordinating carbonate anions

The 22-membered macrocycle, spanning four endocyclic pyrazole groups, viz. 1,4,9,14,17,22,27,28,29,30-decaaza-5,13,18,26-tetramethylpentacyclo[24.2.1. 1(4,7).1(11,14).1(17,20)]-triacontane-5,7(28), 11(29),12,18,20(30),24(27),2 5-octaene (22Pz), rendered the tetranuclear compound [Cu-4(22Pz)(2)(CO3)(2) (MeOH)(2)](ClO4)(4)(MeOH)(4). The copper(II) ions are in distorted octahedr al N3O3 environments. All four pyrazole groups of each macrocycle participa te in the coordination of the copper(II) ions. The cationic part of this co mpound is in fact a dimer of two macrocyclic ligands, each containing two c opper(II) ions bridged by two carbonate ions in the highly unusual pentacoo rdinating fashion.