Geometric and electronic structures of five-coordinate manganese(II) picket fence porphyrin complexes

Three five-coordinate, high spin manganese(II) picket fence porphyrin complexes, [Mn(TpivPP)(L)] (TpivPP = alpha,alpha,alpha,alpha-tetrakis(o-pivalamidophenyl)porphyrinato; L = 1-MeIm (1-methylimidazole), 1-EtIm (1-ethylimidazole) and 2-MeHIm (2-methylimidazole)), are synthesized and studied by single-crystal X-ray, UV-vis and electronic paramagnetic resonance (EPR) spectroscopy. Structural parameters are investigated and compared with analogues. Low temperature (90 K), high field EPR studies of [Mn-(TpivPP)(1-MeIm)] and [Mn(TpivPP)(2-MeHIm)] showed five resonances including characteristic signals at similar to 5.9 and similar to 2.0. The simulations of the EPR spectra give the zero field splitting (zfs) parameters (D, E and lambda) and the hyperfine coupling constant (A).