DOTP−Manganese and −Nickel Complexes: from a Tetrahedral Network with 12-Membered Rings to an Ionic Phosphonate

DOTP (1,4,7,10-tetrakis(methylenephosphonic acid)-1,4,7,10-tetraazacyclododecane) was reacted hydrothermally
with MnCl2·2H2O and Ni(NO3)2·6H2O resulting in two structurally different compounds. Mn[C3NH7(PO3H0.5)]4 crystallizes
in the tetragonal space group P4/ncc, with a = 12.349(2) Å, b = 12.349(2) Å, c = 14.066(4) Å, V = 2144.9(8)
Å3, and Z = 4. Manganese atoms are tetrahedrally bonded by four phosphonate oxygen atoms from four equivalent
ligands. All 12-membered macrocycles are connected in a “zigzag” manner by sharing manganese atoms and
forming 22-membered cavities between each pair of two adjacent macrocycles. Ni[C3NH6(PO3H)]4[Ni(H2O)6] crystallizes
as an ion pair complex. Ni(1) is octahedrally coordinated to two pendent phosphonate oxygen atoms and four
nitrogen atoms from the macrocyclic backbone. Ni(2) is surrounded by six coordinatedly bonded water molecules
to form a hexaqua cation. The manganese complex shows ion exchange capability for Cs+.