Copper(I) complexes of bipyridine and terpyridine with fluorous tails and the formation of crystalline materials with fluorous layers

Copper(I) complexes with perfluorinated tails, (Cu^IL ²AcN)BF₄ and (Cu^IL³AcN)BF ₄, where L² = 6,6′-bis(perfluorohexyl)-2,2′: 6′,2′-terpyridine and L³ = 6,6′-bis(2,2,3,3,4,4,5, 5,6,6,7,7,7-tridecafluoroheptyl)-2,2′-bipyridine and AcN = acetonitrile, were synthesized and their rather unique crystal structures were elucidated. (Cu^IL²AcN)BF₄ crystallizes in a low-symmetry space group, P$\bar {1}$, with a very large unit cell that required synchrotron radiation to locate all atoms. The molecular structure of (Cu^IL²AcN)BF₄ has an asymmetric tetrahedrally distorted square-planar coordination sphere around Cu^I. Eight similar but distinct molecular structures were found. The crystal packing of (Cu ^IL²AcN)(BF₄) has a layered structure with a clear segregation between the terpyridine moieties and the fluorous chains. The terpyridine units are arranged in a "back to back" fashion and tilted 20-25° relative to the interlayer plane, and the layered structure is staggered with offsets of approximately 4 Å between layers. The molecular structure of (Cu^IL³AcN)(BF₄) features a Y-shaped trigonal planar coordination sphere around copper(I). Comparison of the structure with analogous Cu^I(neocuproine)AcN showed that the fluorous tails with the CH₂CH₂ spacers basically have no effect on the bond lengths and angles to Cu¹. The crystal structure of (Cu^IL³AcN)(BF₄) shows a "herring bone" conformation with an approximately 96° angle in the CubipyAcN units. The "herring bone" conformation leads to an accordion-type fluorous layer. Copper(I) complexes of bipyridine (Y-shaped trigonal planar) and terpyridine (tetrahedrally distorted square-planar) with fluorous tails showed crystal packing with segregation of the aromatic units and the fluorous tails. Layered structures that are tilted in two different dimensions as well as "herring bone" structures with accordion-like fluorous layers were observed.