Structural Diversity Ranging from Oligonuclear Complexes to 1-D and 2-D Coordination Polymers Generated by Tetrasubstituted Adamantane and Spirobifluorene Derivatives

Using tetrahedral and tetragonal spacers, seven new complexes have been obtained: [Co(hfac)2(L1)0.5] 1, [Cu2(hfac)4L2] 2, [Co(hfac)2L2] 3, [Co(hfac)2(L2)0.5]·8H2O 4, [AgL2](SbF6)·CH3COOC2H5 5, [Mn(hfac)2(L3)0.5] 6, [Zn(OAc)2(L3)0.5] 7, {L1 = 1,3,5,7-tetrakis(4-cyanophenyl)adamantane, L2 = 2,2′,7,7′-tetracyano-9,9′-spirobifluorene and L3 = 2,2′,7,7′-tetra(4-pyridyl)-9,9′-spirobifluorene, Hhfac = hexafluoroacetylacetone}. Compound 1 exhibits a 2-D grid-like structure with the tetradentate spacer acting as a 4-connecting ligand. The 2,2′,7,7′-tetrasubstituted-spirobifluorene derivatives connect the {MII(hfac)2} entities into a binuclear complex (2), a linear chain (3) and diamond chains (4, 6). The cis or trans configuration of the metal nodes influences the overall topology (MII = CuII, CoII, MnII). Similarly, a 1-D double chain topological motif results by linking zinc ions and L3 in compound 7. Compound 5 is a 2-D coordination polymer featuring a layered framework with square cavities. Compound 5 undergoes a reversible single-crystal-to-single-crystal process, with removal of the solvent molecules (ethyl acetate). The luminescence properties of compounds 5, 7 have been investigated and reveal blue emission with maxima at 402 and 483 nm, respectively. The dynamic magnetic properties and EPR spectrum of 1 have been investigated, revealing the occurrence of slow relaxation of the magnetization that most likely involves a Raman process.