Synthesis and Characterization of the Nickel(II) Complex of a Macrocyclic Schiff Base Ligand with a Single Pendant Coordinating Hydroxyl Arm

Abstract

The synthesis and characterization of a nickel(II) complex of the ligand 8,9,18,19-tetrahydro-7H,17H-dibenzo[f,o][1,5,9,13]dioxadiazacyclohexadecin-18-ol (L) is described. Complex [NiL(NO₃)]NO₃ was prepared by facile template reaction of the appropriate dialdehyde 2-(3-(2-formylphenoxy)-2-hydroxypropoxy)benzaldehyde (1) and 1,3-diaminopropane in the presence of nickel nitrate. X-Ray crystallography indicated that the compound was a six-coordinate complex that contained a pentadentate ligand and an NO₃⁻ anion trans to the alcoholic donor. The blue complex contains nickel(II) in a distorted octahedral environment of N₂O₄ donors, and crystallizes in the monoclinic space group C2/c with a 26.921(10), b 9.075(2), c 21.193(7) Å, β 122.12(2)°, and Z 8. From spectro-scopic and conductivity studies of the complex it has been found that six-coordinate [NiL(NO₃)]⁺ cations and NO₃⁻ anions are formed in solution.