Structure and Magnetic Behavior of CuII MOFs Supported by 1,2,4-Triazolyl-Bifunctionalized Adamantane Scaffold

New triazole-based Cu-II metalorganic frameworks, [Cu(tr(2)ad)(SO4)]center dot 3H(2)O (1), [Cu-3(tr(2)ad)(4)(H2O)(2)(SO4)(2)]SO4 center dot 28H(2)O (2), [Cu-3(tr(2)ad)(4)(H2O)(4)](SiF6)(3)center dot 16H(2)O (3), constructed utilizing a rigid adamantane scaffold, tr82ad = 1,3-bis(1,2,4-triazol-4-yl)adamantane, were prepared hydrothermally, and their crystal structures were determined. The structure of 1 is built up from straight chains of corner-sharing CuN4O2 octahedra supported by short mu(2)-tr (tr = 1,2,4-triazole) and mu(2)-SO42 bridges. The tetradentate character of tr(2)ad results in the formation of layers. The 2D structures of 2 and 3 consist of discrete secondary building blocks [Cu-3(mu(2)-N-1,N-2-tr)(6)] with triple [NN] triazole links between the adjacent Cu centers [the Cu-(tr)-Cu separations are 3.806 and 3.756 angstrom for 2 and 3, respectively]. The distorted octahedral N4O2 environment of the peripheral Cu atoms is completed by water molecules and/or terminal sulfate anions. The linear magnetic clusters, which act as nodes, are joined together at average distances of 11.2 and 15.015.6 angstrom into square-grid-like networks that exploit the double-bridging mu(3)- and mu(4)-bis(triazole) modules. Uncoordinated counteranions and crystal water molecules fill the interlayer space and channels in the complexes and form extensive H-bonding patterns. The exchange integrals J(1) = 9.8 and J(2) approximate to 0 cm(1) for the interaction J(1)((S) over cap (1)(S) over cap (2) + (S) over cap (2)(S) over cap (3)) + J(2)(S) over cap (1)(S) over cap (3) were determined for 3 from magnetic susceptibility data and reproduced by a broken-symmetry DFT calculation. The spin Hamiltonian parameters of 3 were found from high-field electron paramagnetic resonance (EPR) spectra.