Influence of Counteranions on the Structural Modulation of Silver–Di(3-pyridylmethyl)amine Coordination Polymers

The coordination chemistry of a flexible N-donor ligand di(3-pyridylmethyl)amine (dpma) with silver salts has been investigated. Six new silver coordination polymers, namely, [Ag(dpma)(H 2 O)](NO 3 ) ( 1 ), [Ag(dpma)(CF 3 CO 2 )]·1/2H 2 O ( 2 ), [Ag(dpma)](CF 3 SO 3 )·1/2H 2 O ( 3 ), [Ag(dpma)](BF 4 )·3/2H 2 O ( 4 ), [Ag 3 (dpma) 2 (H 2 O)](ClO 4 ) 3 ( 5 ), and [Ag(dpma)](PF 6 ) ( 6 ), have been prepared by slow diffusion reactions. All the polymeric structures of compounds 1 – 6 are described as topologic binodal networks in terms of Ag and dpma building blocks. Compounds 1 – 4 show a one-dimensional ladder-like chain structure, with both Ag and dpma as three-connected T-nodes; compound 5 is an uncommon one-dimensional metallamacrocycle-based chain structure, with Ag as two-connected I-node and dpma as three-connected T-node; compound 6 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 ( 1 and 2 ), trans–trans–anti ( 3 and 4 ), trans–trans–syn ( 3 ), gauche–gauche–syn ( 5 ), and trans–gauche–syn ( 6 ) 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 1 – 6 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 1 – 6 are examined. In addition, the photoluminescent properties of compounds 1 – 6 are investigated in the solid state at room temperature.