Formation of a nona­nuclear copper(II) cluster with 3,5-di­methyl­pyrazolate starting from an NHC complex of copper(I) chloride

The complete nona­nuclear cluster in bis­[1,3-bis­(2,6-di­methyl­phen­yl)imid­azol­ium] di-μ-chlorido-tetra­chlorido­octa­kis­(μ-3,5-di­methyl­pyrazolato)hexa-μ(3)-hydroxido-nona­copper(II) chloro­form disolvate, [HIXy](2)[Cu(9)(μ-pz*)(8)(μ(3)-OH)(6)(μ(2)-Cl)(2)Cl(4)]·2CHCl(3) or (C(19)H(21)N(2))(2)[Cu(9)(C(5)H(7)N(2))(8)Cl(6)(OH)(6)]·2CHCl(3), where pz* is the 3,5-di­methyl­pyrazolyl anion, C(5)H(7)N(2) (−), and HIXy is the 1,3-bis­(2,6-di­methyl­phen­yl)imidazolium cation, C(19)H(21)N(2) (+), is generated by a crystallographic centre of symmetry with a square-planar Cu(II) ion bound to four μ(3)-OH ions lying on the inversion centre. Of the four remaining unique Cu(II) atoms, three adopt CuN(2)O(2)Cl square-pyramidal coordination geometries with the chloride ion in the apical position and one has a distorted CuN(2)OCl tetra­hedral geometry. The dianionic nona­nuclear core can be described as a 24-membered [CuNN](8) ring that contains a Cu(9)O(6)Cl(6) core. The cluster features three intra­molecular O—H⋯Cl hydrogen bonds. In the crystal, weak C—H⋯N and C—H⋯Cl inter­actions link the components. Polynuclear paramagnetic clusters of this type are of considerable inter­est due to their relevance to both the bioinorganic and single-mol­ecule magnets research fields.