Notes. Proton nuclear magnetic resonance and optical spectra of six-co-ordinated high-spin (S= 2) bis(tetrahydrofuran)(3,7,12,17-tetramethyl-8,13-divinylporphyrin-2,18-dipropionato)iron(II) encapsulated in aqueous detergent micelles

Abstract

Proton n.m.r. (500 MHz) and optical spectral studies have been made on the six-co-ordinated high-spin iron(II) haem [FeL(thf)₂](L = 3,7,12,17-tetramethyl-8,13-divinylporphyrin-2,18-dipropionate, thf = tetrahydrofuran) encapsulated in aqueous hexadecyltrimethylammonium bromide micelles. The results are compared with those of the five-co-ordinated high-spin iron(II) haem reported previously. The optical spectrum of the six-co-ordinated species show the Soret band at 415 nm and two other bands at 540 and 564 nm, while for the five-co-ordinated species the Soret band shifts to longer wavelength and a single broad band at 555 nm was obtained. The n.m.r. spectra show a larger downfield shift for the methyl- and meso-proton resonances and a smaller spread of the four methyl resonances for the six-co-ordinated complex as compared to those of five-co-ordinated high-spin haems.