Helical Silver(I)−2,4‘-Bipyridine Chains Organized into 2-D Networks by Metal−Counterion or Metal−Metal Bonding. Structures of [Ag(2,4‘-bipyridine)]X (X^- = NO₃^- or ClO₄^-)

Abstract

Two compounds, [Ag(2,4‘-bpy)]NO 3 ( 1 ) and [Ag(2,4‘-bpy)]ClO 4 ( 2 ), were obtained from self-assembly of AgX (X = NO 3 -, ClO 4 - ) with 2,4‘-bipyridine (2,4‘-bpy). 1 crystallizes in the orthorhombic space group Pbca, with a = 11.2884(7) Å, b = 11.3981(10) Å, c = 16.5299(13) Å, and Z = 8, while 2 crystallizes in the monoclinic space group P 2 1 /c, with a = 10.6361(4) Å, b = 9.9896(4) Å, c = 11.2661(6) Å, β = 98.527(4)°, and Z = 4. Both complexes consist of helical [Ag(2,4‘-bpy)] ∞ chains that are surrounded by nitrate or perchlorate counterions. Adjacent helical chains are racemic. The Ag I atom is linked to two nitrogen atoms of the 2-pyridyl and 4‘-pyridyl groups from two different 2,4‘-bpy ligands as well as to the oxygen atom of the counterion. In 1, another oxygen atom of the counterion is weakly coordinated to the Ag I atom of an adjacent chain, thus bridging the helical chains into a wavy 2-D network structure, whereas in 2, adjacent helical chains are linked by the weak ligand-unsupported metal−metal interactions, resulting in an open 2-D network with compressed hexagons as building units. The structures of 1 and 2 imply the role that counterions may play in the framework construction.