title: Assistance of the iron porphyrin ligands to the binding interaction between the Fe center and small molecules in solution.
abstract: Solute-solvent electronic structure interactions of iron porphyrin at very low concentration in dichloromethane (CH2Cl2) liquid solution are reported. Two iron porphyrin complexes are investigated here-iron octaethylporphyrin chloride (FeOEP-Cl) and iron tetraphenylporphyrin chloride (FeTPP-Cl)-using X-ray absorption and emission spectroscopy at the Fe L2,3 edge, and spectra are interpreted with the help of density functional theory/restricted open-shell configuration interaction singles (DFT/ROCIS) calculations. It is argued that the Fe center of FeOEP-Cl is more capable of binding small solvent molecules, exemplified here for Cl2CH2, than FeTPP-Cl in solution. The proposed binding mechanism is through the assistance of the dipole interaction between the porphyrin-ligand system and the solvent molecule, in a situation where the ligand structure and arrangement maximize the binding interactions. Our studies demonstrate that even small ligands, depending on their structure and arrangement, can have considerable effects on porphyrin's metal center chemistry in liquid solution.
authors.affiliation: Joint Ultrafast Dynamics Lab in Solutions and at Interfaces (JULiq), Helmholtz-Zentrum Berlin für Materialien und Energie , Albert-Einstein-Strasse 15, D-12489 Berlin, Germany.
authors.forename: Jie
authors.initials: J
authors.lastname: Xiao
authors.forename: Ronny
authors.initials: R
authors.lastname: Golnak
authors.forename: Kaan
authors.initials: K
authors.lastname: Atak
authors.forename: Mika
authors.initials: M
authors.lastname: Pflüger
authors.forename: Marvin
authors.initials: M
authors.lastname: Pohl
authors.forename: Edlira
authors.initials: E
authors.lastname: Suljoti
authors.forename: Bernd
authors.initials: B
authors.lastname: Winter
authors.forename: Emad F
authors.initials: EF
authors.lastname: Aziz
mesh_terms: D002712:Chlorides / Q000737:chemistry; D003198:Computer Simulation; D007501:Iron / Q000737:chemistry*; D008752:Methylene Chloride / Q000737:chemistry*; D008956:Models, Chemical; D015394:Molecular Structure; D011166:Porphyrins / Q000737:chemistry*; D012996:Solutions; D012997:Solvents / Q000737:chemistry; D013052:Spectrometry, X-Ray Emission
chemical_list: D002712:Chlorides; D011166:Porphyrins; D012996:Solutions; D012997:Solvents; D008752:Methylene Chloride; D007501:Iron