Joseph H. Nettleman

Structure and physical properties of substituted malonate divalent metal coordination polymers with dipyridylamine co-ligands: acentric chain, herringbone layer, and novel binodal network topologies

Three divalent metal coordination polymers and one molecular species containing 4,4′-dipyridylamine (dpa) and substituted malonate ligands have been prepared and structurally characterized by single crystal X-ray diffraction. The degree of substitution and different coordination environments promote significant structural diversity in this system. {[Cu(mmal)(Hmmal)(Hdpa)]·H2O}n (1, mmal = methylmalonate) crystallizes in an acentric space group and possesses 1-D coordination polymer chain motifs containing [Cu(OCO)]n linkages. {[Cu3(dmmal)2(dpa)3](ClO4)2·2H2O}n (2, dmmal = dimethylmalonate) manifests an unprecedented (4,5)-connected binodal network with (4462)(4664)2 topology, and contains equatorial–equatorial bridged linear {Cu3O2} trimeric units. {[Cd2(dmmal)2(dpa)(Hdpa)](ClO4)·2H2O·CH3CH2OH}n (3) displays (6,3) herringbone layers, while {[Co(dmmal)2(Hdpa)2]·6H2O} (4) has co-crystallized neutral coordination complexes and hydrogen-bonded hexameric water molecule aggregations. Ultraviolet irradiation of a sample of 3 resulted in blue-violet light emission due to π–π* transitions within the dpa and Hdpa+ ligands. Variable temperature magnetic studies indicated antiferromagnetic coupling along the {Cu(OCO)}n chains in 1 and within the {Cu3O2} linear trimers in 2.

catena-Poly[[[tetra­aqua­cobalt(II)]-μ-4,4′-bipyridine-κ2N:N′] bis­(perchlorate) 4,4′-bipyridine disolvate dihydrate]

In the title compound, {[Co(C10H8N2)(H2O)4](ClO4)2·2C10H8N2·2H2O}n, slightly distorted octahedrally coordinated CoII ions situated on inversion centers are linked into polycationic chains through 4,4′-bipyridine tethering ligands. These are connected into supramolecular layers by hydrogen bonding involving aqua ligands, perchlorate anions and uncoordinated water molecules. A twofold interpenetrated primitive cubic supramolecular network is formed by the interaction of pseudo-layers by hydrogen bonding between aqua ligands and unligated 4,4′-bipyridine molecules.