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Photochemistry of iron pentacarbonyl in poly(vinyl chloride), polytetrafluoroethylene and low‐density polyethylene films at 12–298 K: Infrared spectroscopic evidence for the reversible formation of the carbon monoxide loss products iron tetracarbonyl and tricarbonyl, and their reactions with species in the films
Author(s) -
Hooker Richard H,
Rest Antony J
Publication year - 1990
Publication title -
applied organometallic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 71
eISSN - 1099-0739
pISSN - 0268-2605
DOI - 10.1002/aoc.590040209
Subject(s) - chemistry , low density polyethylene , tetrahydrofuran , vinyl chloride , polyethylene , solvent , carbon monoxide , dichloromethane , molecule , ethylene , propionaldehyde , infrared spectroscopy , hexane , olefin fiber , polymer chemistry , inorganic chemistry , polymer , organic chemistry , catalysis , aldehyde , copolymer
Abstract Infrared spectroscopic evidence (CO stretching region) is presented to show that near‐UV irradiation (280 < λ < 350 nm) of Fe(CO) 5 in lowdensity polyethylene (LDPE), poly(vinyl chloride) (PVC) and polytetrafluoroethylene (PTFE) films at ca 12 K affords the coordimatively unsturated species Fe(CO) 4 and Fe(CO) 3 . The species Fe(CO) 3 recombines with CO at ca 60 K whilst Fe(CO) 4 recombines at ca 80 K. The species also react with the polymeric medium and with residual solvent molecules [hexane, dichloroethane, tetrahydrofuran (THF)] in the films. The species Fe(CO) 4 …(PVC) and Fe(CO) 4 …(dichloroethane), in which the Fe(CO) 4 fragments are probably coordinated by chlorine atoms in the PVC or solvent molecules, are less thermally stable than Fe(CO) 4 (THF) and are converted to Fe(CO) 5 on warming the films to above ca 140 K. Similarly, the species Fe(CO) 4 (LDPE) and Fe(CO) 4 (hexane), arising from interaction of Fe(CO) 4 with hydrogen atoms in the polymer or solvent molecules, are converted to Fe(CO) 5 on warming the films from ca 100 K to ca 130 K. The major product formed in LDPE films at 298 K is probably Fe(CO) 4 (olefin) arising from olefin impurities in the poly(ethylene), whilst in the PVC films in the presence or absence of THF the major product resembles (η 3 –C 3 H 5 )Fe(CO) 3 Cl, i.e. Fe(CO) 4 and Fe(CO) 3 fragments bound to allyl chloride impurities in the PVC. The potential of polymer films for trapping and characterizing unstable species is discussed.