Silver Coodination Polymers with Flexible Ligands. Syntheses, Crystal Structures, and Effect of the Counteranion and the Solvent on the Structure of Complexes [Ag<b>L</b>X]_∞ of the Bis(Phenylthio)methane Ligand <b>L</b><b>¹</b> with Silver(I) Salts, X = ClO₄^-, BF₄^-, CF₃COO^-, CF₃SO₃^-, CF₃CF₂CF₂COO^-, and ^-OOCCF₂CF₂COO^-

Abstract

A number of complexes were synthesized to rationalize the structures of Ag(I) complexes with a small flexible bidentate ligand, bis(phenylthio)methane, when the anion is varied. We compared two similar “spherical” anions, ClO4- (1) and BF4- (2), as well as two slightly “elongated” ones, CF3COO- (3) and CF3SO3- (4, 5). Complexes with a longer anion, CF3CF2CF2COO- (6), and a diacid, -OOCCF2CF2COO- (7), were also investigated. All the compounds studied form a 1D-coordination polymer. The coordination polymers of 1−4 are of the type [Ag−ligand−]∞ and adopt two distinct conformations: gauche−trans−gauche for 1, 2, and 4, and gauche−gauche−gauche for 3. The anions in 1−4 are coordinated to the silver atoms through a single O or F atom. All these 1D-chains are associated through weak van der Waals interactions into 2D-layer structures. Solvent-induced supramolecular isomerism was observed with the CF3SO3- anion. With diethyl ether, the 1D-coordination polymer of 4 was observed, as indicated above, while a two-stranded chain comprising a 16-membered macrocyclic structure, Ag4L14, was noted when petroleum ether was used, 5. The macrocycles are connected through a small cyclic (CF3SO3···Ag···)2 dimeric unit. Another type of double-stranded ladder-like structure was noted for 6. Each of the two heptafluorobutyrate anions is coordinated through its oxygen atoms to two distinct silver atoms to form a dimeric unit. This, in turn, is connected to another unit through two Ag−S coordination bonds. The repeat unit of this coordination polymer is based on a 10-membered Ag4L12 macrocycle. In compound 7, with the tetrafluorosuccinate anion, one observes another type of 1D-polymer best described as a [Ag2−tetrafluorosuccinate−]∞ chain reinforced by Ag−ligand−Ag bonds. Most complexes containing fluorine atoms have C(H)···F or C(H2)···F short contacts (2.998−3.203 Å) that correlate with an FTIR absorption band around 521 cm-1. Relatively short Ag···Ag interactions are found in both 6 and 7.