| Abstract: | The blue tetranuclear CuII complexes {Cu(bpy)(OH)]4Cl2}Cl2 · 6 H2O ( 1 ) and {Cu(phen)(OH)]4(H2O)2}Cl4 · 4 H2O ( 2 ) were synthesized and characterized by single crystal X‐ray diffraction. ( 1 ): P 1 (no. 2), a = 9.240(1) Å, b = 10.366(2) Å, c = 12.973(2) Å, α = 85.76(1)°, β = 75.94(1)°, γ = 72.94(1)°, V = 1152.2(4) Å3, Z = 1; ( 2 ): P 1 (no. 2), a = 9.770(3) Å, b = 10.118(3) Å, c = 14.258(4) Å, α = 83.72(2)°, β = 70.31(1)°, γ = 70.63(1)°, V = 1252.0(9) Å3, Z = 1. The building units are centrosymmetric tetranuclear {Cu(bpy)(OH)]4Cl2}2+ and {Cu(phen)(OH)]4(H2O)2}4+ complex cations formed by condensation of four elongated square pyramids CuN2(OH)2Lap with the apical ligands Lap = Cl, H2O, OH. The resulting Cu4(μ2‐OH)2(μ3‐OH)2] core has the shape of a zigzag band of three Cu2(OH)2 squares. The cations exhibit intramolecular and intermolecular π‐π stacking interactions and the latter form 2D layers with the non‐bonded Cl– anions and H2O molecules in between (bond lengths: Cu–N = 1.995–2.038 Å; Cu–O = 1.927–1.982 Å; Cu–Clap = 2.563; Cu–Oap(OH) = 2.334–2.369 Å; Cu–Oap(H2O) = 2.256 Å). The Cu…Cu distances of about 2.93 Å do not indicate direct interactions, but the strongly reduced magnetic moment of about 2.74 B.M. corresponds with only two unpaired electrons per formula unit of 1 (1.37 B.M./Cu) and obviously results from intramolecular spin couplings (χm(T‐θ) = 0.933 cm3 · mol–1 · K with θ = –0.7 K). |
