title: Nuclear resonance vibrational spectra of five-coordinate imidazole-ligated iron(II) porphyrinates.
abstract: Nuclear resonance vibrational spectra have been obtained for six five-coordinate imidazole-ligated iron(II) porphyrinates, [Fe(Por)(L)] (Por = tetraphenylporphyrinate, octaethylporphyrinate, tetratolylporphyrinate, or protoporphyrinate IX and L = 2-methylimidazole or 1,2-dimethylimidazole). Measurements have been made on both powder and oriented crystal samples. The spectra are dominated by strong signals around 200-300 cm(-1). Although the in-plane and out-of-plane vibrations are seriously overlapped, oriented crystal spectra allow their deconvolution. Thus, oriented crystal experimental data, along with density functional theory (DFT) calculations, enable the assignment of key vibrations in the spectra. Molecular dynamics are also discussed. The nature of the Fe-N(Im) vibrations has been elaborated further than was possible from resonance Raman studies. Our study suggests that the Fe motions are coupled with the porphyrin core and peripheral groups motions. Both peripheral groups and their conformations have significant influence on the vibrational spectra (position and shape).
authors.affiliation: Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, PR China. cjhu@suda.edu.cn
authors.forename: Chuanjiang
authors.initials: C
authors.lastname: Hu
authors.forename: Alexander
authors.initials: A
authors.lastname: Barabanschikov
authors.forename: Mary K
authors.initials: MK
authors.lastname: Ellison
authors.forename: Jiyong
authors.initials: J
authors.lastname: Zhao
authors.forename: E Ercan
authors.initials: EE
authors.lastname: Alp
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Sturhahn
authors.forename: Marek Z
authors.initials: MZ
authors.lastname: Zgierski
authors.forename: J Timothy
authors.initials: JT
authors.lastname: Sage
authors.forename: W Robert
authors.initials: WR
authors.lastname: Scheidt
mesh_terms: D005296:Ferrous Compounds / Q000737:chemistry*; D007093:Imidazoles / Q000737:chemistry*; D008665:Metalloporphyrins / Q000737:chemistry*; D033362:Powder Diffraction
chemical_list: D005296:Ferrous Compounds; D007093:Imidazoles; D008665:Metalloporphyrins