Inorganic Chemistry, Vol.47, No.19, 8957-8971, 2008
Anion-dependent self-assembly of silver(I) and diaminotriazines to coordination polymers: Non-covalent bonds and role interchange between silver and hydrogen bonds
New coordination polymers have been obtained by the self-assembly of silver salts AgX (X = BF4, PF6, CF3SO3) and 2,4-diamino-6-R-1,3,5-triazines L (R = phenyl and p-tolyl) of formulas AgLX (1-6). A complex of different stoichiometry, [Ag3L2(H2O)(acetone)(2)](BF4)(3), 7 (R = phenyl), has also been ynthesized. The three-dimensional structures of five compounds have been determined by X-ray diffraction studies. For the AgLX complexes, when X = BF4 and R = phenyl or p-tolyl, chiral chains with alternating Ag and L are formed. The chains are cross-linked by the counteranions in a three-dimensional fashion through hydrogen bonds and weak Ag...F interactions giving rise to a structure with solvent-filled channels. Different and more compact structures have been found when the counteranion is CF3SO3 (OTf). When R = phenyl enyl, sheets are formed which consist of [Ag-2(OTf)(2)L-2] units with double triflate bridges and which contain columns of pi-pi stacked arenes. Hydrogen bonds connect the sheets. When AgOTf is used and R is p-tolyl, a different and unusual ladderlike structure is obtained in which the rungs are double asymmetric bridges consisting of the triflate groups bonded to Ag in kappa O-2,mu(2)-O and kappa O-1,mu(2)-O fashion. The ladders are parallel to each other and are mutually linked by N-H...N hydrogen bonds to give a 3D architecture. A very similar ladderlike structure has been found for 7 but with a water molecule and a BF4- group acting as bridges. The role played by the hydrogen bonds in complex 6 to form the 3-D structure is played in 7 by [Ag(acetone)2] fragments. The noncovalent interactions play an important role in the different solid-state 3D structures. The behavior of the new derivatives in solution has also been analyzed. A new species has been detected at low temperatures, and this exhibits restricted rotation of the phenyl ring.