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Influence of Counteranions on the Structural Modulation of Silver–Di(3-pyridylmethyl)amine Coordination Polymers
The
coordination chemistry of a flexible N-donor ligand diÂ(3-pyridylmethyl)Âamine
(dpma) with silver salts has been investigated. Six new silver coordination
polymers, namely, [AgÂ(dpma)Â(H<sub>2</sub>O)]Â(NO<sub>3</sub>)
(<b>1</b>), [AgÂ(dpma)Â(CF<sub>3</sub>CO<sub>2</sub>)]·1/2H<sub>2</sub>O (<b>2</b>), [AgÂ(dpma)]Â(CF<sub>3</sub>SO<sub>3</sub>)·1/2H<sub>2</sub>O (<b>3</b>), [AgÂ(dpma)]Â(BF<sub>4</sub>)·3/2H<sub>2</sub>O (<b>4</b>), [Ag<sub>3</sub>(dpma)<sub>2</sub>(H<sub>2</sub>O)]Â(ClO<sub>4</sub>)<sub>3</sub> (<b>5</b>), and [AgÂ(dpma)]Â(PF<sub>6</sub>) (<b>6</b>), have been prepared by slow diffusion reactions. All the polymeric
structures of compounds <b>1</b>–<b>6</b> are described
as topologic binodal networks in terms of Ag and dpma building blocks.
Compounds <b>1</b>–<b>4</b> show a one-dimensional
ladder-like chain structure, with both Ag and dpma as three-connected
T-nodes; compound <b>5</b> is an uncommon one-dimensional metallamacrocycle-based
chain structure, with Ag as two-connected I-node and dpma as three-connected
T-node; compound <b>6</b> is a two-dimensional honeycomb-like
layer structure, with both Ag and dpma as three-connected Y-nodes.
Within the structures, the dpma ligand adopts a variety of structure
conformations including gauche–trans–anti (<b>1</b> and <b>2</b>), trans–trans–anti (<b>3</b> and <b>4</b>), trans–trans–syn (<b>3</b>), gauche–gauche–syn (<b>5</b>), and trans–gauche–syn
(<b>6</b>) conformations. For these Ag–dpma coordination
polymers, the structural diversity and complexity are most likely
attributed to the different coordinating nature, hydrogen-bonding
propensity, and templating effect of the counteranions and solvent
molecules. Solution studies suggest that compounds <b>1</b>–<b>6</b> would disaggregate to break down the polymeric structures
and then to give multiple rapidly exchanging solution species in DMSO
or acetonitrile. The thermal stabilities of compounds <b>1</b>–<b>6</b> are examined. In addition, the photoluminescent
properties of compounds <b>1</b>–<b>6</b> are investigated
in the solid state at room temperature