Structural Relationships between the Hemiporphyrazine Macrocyclic Ligand and its Metal Complexes. I.: Saddle Shaped Neutral Ligand Hydrate, C26H16N8·‐H2O, and Nickel Complex, [Ni(C26H14N8)]

Crystal and molecular structures of the neutral ligand hydrate, C24H16N8·H2O, and the diamagnetic nickel(II) complex, [Ni(C C24H16N8)], have been determined by three‐dimensional X‐ray crystallography. Pertinent data are: C24H16N8·H2O, Pnmm with Z=2, a=4.6142(3), b=14.7687(7), c=15.0650(5) Å, R=0.068, Rw = 0.038; [Ni(C24H16N8), 12/c with Z=4, a=22.0137(11), b=3.7637(4), c=23.4742(11) Å, β=92.7(1)°, R = 0.039, Rw=0.025. The overall conformations of the neutral ligand and the Ni(II) complex are similar, both have a pronounced saddle shape. The Ni(II) ‐N bond distances in the Ni‐complex are 1.861(2) and 1.998(2) Å. The distances from nitrogen atoms to the center of the ring in free ligand are 2.020(3) and 2.220(3)Å, which arc significantly longer than those of Ni(II) complex A detailed comparison about the core size with similar ligand is presented.