X-ray structural analysis, electrochemistry,13C NMR spectroscopy, and infrared spectroscopy of the diacetylated Schiff base complexes [Ni(Me2Ac2H2malen)] and [Ni(Me2Ac2Me2malen)] are reported. Differences in the number of methyl groups on the chelate backbone (two for [Ni(Me2Ac2H2malen)], four for [Ni(Me2Ac2Me2malen)]) cause the acetyl groups to be rotated out of the NiN202plane by 16.8 and 58.2°, respectively. Electrochemical measurements on the diacetylated and analogous deacetylated complexes show that delocalization effects from the acetyl groups have been decreased by the rotating of the acetyl groups out of the chelate plane. This interpretation is supported by13C NMR and infrared spectroscopic measurements. As such, the use of steric effects to regulate electronic effects has been demonstrated. [Ni(Me2Ac2H2malen)] crystallized in the monoclinic system (P21/c) with unit cell dimensions a = 14.686 (2) Å, b~ 17,734 (3) Å, c = 11.412(1) Å, β = 101.16 (1)°, and Z = 8; R = 0.049 and Rw= 0.054 for 2730 observed reflections. [Ni(Me2Ac2Me2malen)] crystallized in the monoclinic system (C2/c) with unit cell dimensions a = 7.689 (2) Å, b = 8.686 (2) Å, c = 25.579 (9) Å, β = 103.84 (3)°, and Z = 4; R = 0.042 and Rw = 0.042 for 1370 observed reflections.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry
- Inorganic Chemistry