Rare‐Earth‐Metal Coordination Polymers: Synthesis and Crystal Structures of Five New Adipinates, [M2(Adi)3(H2O)4](AdiH2)(H2O)4 (M = La, Nd), [Er(Adi)(H2O)5]Cl(H2O) and [M(Adi)(H2O)5](NO3)(H2O) (M = Gd, Er)
The new rare‐earth compounds [M2(Adi)3(H2O)4](AdiH2)(H2O)4 (M = La (1), Nd (2)), [Er(Adi)(H2O)5]Cl(H2O) (3) and [M(Adi)(H2O)5](NO3)(H2O) (M = Gd (4), Er (5)) were obtained from the reaction of adipinic acid with La(OH)3·xH2O, Nd2O3, ErCl3·6H2O, Gd(NO)3·xH2O and Er2O3, respectively. Their crystal structures were determined by single‐crystal X‐ray diffraction. The coordination polymers [M2(Adi)3(H2O)4](AdiH2)(H2O)4 crystallize in the triclinic space group ${\rm P}{\bar 1}$ (no. 2) with a = 875.4(1), b = 1000.4(2), c = 1179.0(2) pm, α = 74.70(1), β = 69.85(1), γ = 86.18(2)° and Z = 1 (crystal data for M = La, (1)). The quasi‐isostructural compounds [Er(Adi)(H2O)5]Cl(H2O) (3) and [M(Adi)(H2O)5](NO3)(H2O) (M = Gd (4), Er (5)) crystallize with monoclinic symmetry, space group C2/c (no. 15) with lattice parameters of a = 1231.5(1), b = 1532.6(1), c = 895.4(1) pm, β = 123.44(1)° and Z = 4 (crystal data for (3)). The rare‐earth cations have the coordination numbers 10 (1, 2) and 9 (3, 4 and 5), respectively. The compounds [M2(Adi)3(H2O)4](AdiH2)(H2O)4 are constructed of infinite chains of edge‐sharig [MO8(H2O)2] polyhedra that are cross‐linked by adipinic acid molecules to form framework structures. In [Er(Adi)(H2O)5]Cl(H2O) (3) and [M(Adi)(H2O)5](NO3)(H2O) (M = Gd (4), Er (5)) the central cations are bridged by adipinic acid molecules in a bidentate‐chelating manner to positively charged zigzag chains. Between these the counter ions and crystal water molecules are incorporated.