Crystal structures of three copper(II)–2,2′-bi­pyridine (bpy) compounds, [Cu(bpy)(2)(H(2)O)][SiF(6)]·4H(2)O, [Cu(bpy)(2)(TaF(6))(2)] and [Cu(bpy)(3)][TaF(6)](2) and a related coordination polymer, [Cu(bpy)(H(2)O)(2)SnF(6)](n)

We report the hydro­thermal syntheses and crystal structures of aqua­bis­(2,2′-bi­pyridine-κ(2) N,N′)copper(II) hexa­fluorido­silicate tetra­hydrate, [Cu(bpy)(2)(H(2)O)][SiF(6)]·4H(2)O (bpy is 2,2′-bi­pyridine, C(10)H(8)N(2)), (I), bis­(2,2′-bi­pyridine-3κ(2) N,N′)-di-μ-fluorido-1:3κ(2) F:F;2:3κ(2) F:F-deca­fluorido-1κ(5) F,2κ(5) F-ditantalum(V)copper(II), [Cu(bpy)(2)(TaF(6))(2)], (II), tris­(2,2′-bi­pyridine-κ(2) N,N′)copper(II) bis[hexa­fluorido­tantalate(V)], [Cu(bpy)(3)][TaF(6)](2), (III), and catena-poly[[di­aqua­(2,2′-bi­pyridine-κ(2) N,N′)copper(II)]-μ-fluorido-tetra­fluorido­tin-μ-fluorido], [Cu(bpy)(H(2)O)(2)SnF(6)](n), (IV). Compounds (I), (II) and (III) contain locally chiral copper coordination complexes with C (2), D (2), and D (3) symmetry, respectively. The extended structures of (I) and (IV) are consolidated by O—H⋯F and O—H⋯O hydrogen bonds. The structure of (III) was found to be a merohedral (racemic) twin.