Linking two distinct layered networks of nanosized {Ln18} and {Cu24} wheels through isonicotinate ligands

A new series of heterolanthanide (III) -copper(I) wheel-clustercomplexes [Ln(6)(mu(3)-O)(2)](IN)(18)-[CU8(mu(4)-I)(2)(mu(2)-I)(3)]center dot H3O (IN=isonicotinate; Ln = Y 1, Nd 2, Dy 3, Gd 4, Sm 5, Eu 6, Tb 7) were prepared by hydro-thermal reaction at low pH. X-ray crystallographic studies reveal that two unusual trinuclear [Ln(3)(mu(3)-0)] and tetra-nuclear [CU4(mu(4)-I)] cores are successfully used as secondary building units to make two different nanosized wheels [Ln(18)(mu(3)-O)(6)(CO2)(48)](6-), {Ln(18)}, and [CU24(mu(4)-I)6(mu(2)-I)(12)](6+), {CU24}, with 12-rings and a diameter of 26.7 and 26.4 angstrom, respectively. The wheels are further assembled into two-dimensional (2D) {Ln(18)} and {CU24} networks, the linkages between two distinct layered networks of {Ln(18)} and {CU24} wheels by IN pillars along the c axis giving a series of unprecedented three-dimensional (3D) sandwich frameworks. To our knowledge, compounds 1-7 are the first examples containing two different layered networks of nanosized Ln and transition metal (TM) wheels in wheel-cluster chemistry. The IR, UV/Vis, thermogravimetric analysis (TGA), luminescent, and magnetic properties of these complexes were also studied.