Syntheses and structural characterizations of sheet- and column-like lanthanide-transition metal arrays:: The effect of hydrogen bonding on the structure when K+ is replaced by [NH4]+

Sheet- and column-like cyanide bridged lanthanide-transition metal arrays were synthesized through metathesis reactions between anhydrous LnCl3 (Ln = Eu, Yb) and A2[M(CN)4] (A = K+, NH4+; M = Ni, Pt) in a 1:2 molar ratio in DMF (DMF = N,N-dimethylformamide) solution. Single-crystal X-ray analysis revealed that complexes of formula {K(DMF)7Ln[M(CN)4]2}∞ (Ln = Eu, M = Ni, 1; Ln = Yb, M = Pt, 2) consist of infinite layers of neutral, puckered sheets that contain hexagonal rings of composition {(DMF)10Ln2[M(CN)4]3}6 with interstitial (DMF)4K2[M(CN)4] units located between the layers. The sheet structure is generated through the repeating (DMF)10Ln2[M(CN)4]3 unit with trans cyanide ligands in [M(CN)4]2- serving as bridges. The column-like complex {(NH4)(DMF)4Yb[Pt (CN)4]2}∞, 3, is formed when NH4+ replaces K+. It consists of infinite, negatively charged, square, parallel columns bundled through N-H···NC hydrogen bonds between NH4+ and terminal CN from the columns. Cis cyanide ligands in [Pt(CN)4]2- units serve as bridges. Complex 3 is the first known example where Ln(III) centers are coordinated to four [M(CN)4]2- units. Bicapped (square face) trigonal prismatic coordination geometries were observed for Ln(IlI) centers in 1 and 2. Square antiprismatic geometry for Yb(III) centers are observed in 3. Crystal data for 1: triclinic space group P1̄, a = 8.797(2) Å, b = 15.621(3) Å, c = 17.973(6) Å, α = 105.48(2)°, β = 98.60(2)°, γ = 98.15(2)°, Z = 2. Crystal data for 2: triclinic space group P1̄, a = 8.825(1) Å, b = 15.673(1) Å, c = 17.946(1) Å, α = 105.46(2)°, β = 99.10(1)°, γ = 98.59(1)°, Z = 2. Crystal data for 3: monoclinic space group P21/c, a = 9.032(1) Å, b = 29.062(1) Å, c = 15.316(1) Å, β = 94.51(1)°, Z = 2.