Crystal structure analyses of divalent metal cation complexes with neutral noncyclic ionophores. II. Mg2+ and Ca2+ complexes ofN,N,N′N′-tetracyclohexyl-3-oxapentanediamide

The crystal structures of the Mg(NCS)₂ and Ca(NCS)₂ complexes withN,N,NN-tetracyclohexyl-3-oxapentanediamide are discussed: (1) (C₂₈H₄₈ O₃N₂)₂·Mg(NCS)₂,M _r =1061.9, monoclinic, space groupP2₁/n,a=14.048(4),b=24.672(7),c=19.481(6) Å,=78.79(2)°,V=6623.1 ų,Z=4,d _m =1.09,d _x =1.06g cm^–3,R=0.164 for 2350 unique diffractometer data; (2) (C₂₈H₄₈O₃N₂)₃·Ca(NCS)₂,M _r =1538.4, monoclinic, space groupP2₁ (No. 4),a=14.470(3),b=19.334(5),c=17.082(4) Å,=103.72(1)°,V=4642.6ų,Z=2,d _m =1.11,d _x =1.10g cm^–3,R=0.059 for 4596 unique diffractometer data. Compound (1) is an octahedral Mg²⁺complex in which three O atoms of one ligand molecule and the two carbonyl O atoms of the other together with the N atom of a thiocyanate ion occupy the coordination sites. In complex (2) the Ca²⁺ions are nine-coordinated by the O atoms of three ligand molecules.