Synthesis and Crystal Structure of Two Cu(II)-Benzene-1,2,4,5- Tetracarboxylates With Three-Dimensional Open Frameworks

Two new three-dimensional frameworks with zeolite-like channels were prepared in the presence of 1,6-diaminohexane. Cu1.5(H3N–(CH2)6–NH3)0.5[C6H2(COO)4]·5H2O (1) crystallizes in the triclinic space group P-1 with a = 772.56(7), b = 1110.36(7), c = 1111.98(8) pm, α = 98.720(7)°, β = 108.246(9)°, and γ = 95.559(7)°. Cu2(H3N–(CH2)6– NH3)0.5(OH)[C6H2(COO)4]·3H2O (2) crystallizes in the monoclinic space group P2/c with a = 1159.34(11), b = 1059.44(7), c = 1582.2(2) pm, and β = 106.130(11)°. The Cu2 coordination polyhedra are connected by [C6H2(COO)4]4– anions to yield three-dimensional frameworks with wide centrosymmetric channel-like voids. Complex 1 reveals voids extending along [100] with diagonals of 900 pm and 300 pm, whereas in complex 2 the diagonal of the nearly rectangular crossection of the channels extending parallel to [001] is 900 pm. The negative excess charges of the frameworks are compensated by [H3N–(CH2)6–NH3]2 cations, which occupy the voids along with water molecules. The [H3N–(CH2)6–NH3]2 cations are not connected to Cu2 and have served as templates.