Orientation of Ag I Ions in Coordination Architectures through Ligand Conformation and Anion Binding: from Polymeric Chains to Discrete Squares

Five new complexes containing Ag I salts and the ligand 3,4‐dipyridyl ketone ( L 34 ) were synthesized and characterized, namely {[Ag L 34 ]ClO 4 } ∞ ( 1 ), {[Ag L 34 ]BF 4 } ∞ ( 2 ), {Ag L 34 NO 3 } ∞ ( 3 ), {Ag L 34 CF 3 CO 2 } ∞ ( 4 ) and [Ag L 34 CF 3 SO 3 ] 4 ( 5 ). Both the anion and the ligand conformation were found to affect the structure packing. This set of 1:1 M/L structures demonstrated the role of anion binding and ligand conformation in determining the molecular architecture; the increasing alignment of cations in neighboring M‐L chains in structures 1 – 4 can be attributed to the anions' ability to coordinate to Ag I cations. The conformation of the ligand was shown to determine whether a discrete or polymeric architecture formed. In complexes 1 – 4 the N3 py atom was in a cis orientation, with 1 and 2 forming offset chains held together in 2‐D sheets. The anion in 3 helped link 1‐D chains together to form double chains with the double chains offset in the 2‐D sheet. Complex 4 was present as a 2‐D sheet, with the bifurcating CF 3 CO 2 – anion causing the alignment of the Ag I cations within the sheet. Complex 5 was the only discrete species, with L 34 adopting a trans arrangement and acting as corner pieces of a molecular square. DFT calculations showed that the two conformations of the free ligand had a difference in energy of only 2.1 kJ mol –1 .