title: Analysis of problematic complexing behavior of ferric chloride with N,N-dimethylformamide using combined techniques of FT-IR, XPS, and TGA/DTG.
abstract: A problematic coordination behavior of highly hygroscopic FeCl(3) in DMF solution was studied. From the compositional and structural analyses for the adduct of FeCl(3)/DMF using various techniques such as FTIR, elemental analysis, UV/vis, XPS, and TGA/DTG, it was found that the iron cation exists in the form of an Fe(3+) cation and coordinates via the carbonyl oxygen atom of amide bond in DMF. The analyses of both FT-IR and XPS C 1s spectra for the adduct revealed that 2.1 molecules of DMF coordinate with a more electron-deficient Fe(3+); otherwise 1.2 molecules of DMF coordinated with a relatively electron-rich Fe(3+). The Cl 2p spectrum indicated that the electron-deficient Fe(3+) coordinated with two chlorine ions and the electron-rich Fe(3+) with four chlorines so that the chemical formula of the adduct is of [FeCl(2)(DMF)(1.2)(H(2)O)(2.7)](+)[FeCl(4)(DMF)(2.1)](-). The water molecules in the adduct were found chemisorbed rather than physisorbed, with a singular binding energy.
authors.affiliation: Enviro-Polymers Design Laboratory, Hyperstructured Organic Materials Research Center (HOMRC) and School of Materials Science and Engineering, Seoul National University E445-F, Seoul 151-744, Korea.
authors.forename: Young Jeon
authors.initials: YJ
authors.lastname: Kim
authors.forename: Chong Rae
authors.initials: CR
authors.lastname: Park