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Tertiary Phosphane‐Diiodine Compounds: Are They Molcular Adducts or Iodophosphonium Iodides?
Author(s) -
Deplano Paola,
Godfrey Stephen M.,
Lsaia Francesco,
McAuliffe Charles A.,
Mercurp Maria Laura,
Trogu Emanuele F.
Publication year - 1997
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19971300226
Subject(s) - adduct , chemistry , ionic bonding , acceptor , nuclear magnetic resonance spectroscopy , dichloroethane , raman spectroscopy , photochemistry , medicinal chemistry , stereochemistry , solvent , organic chemistry , ion , physics , optics , condensed matter physics
The solid‐state and solution structures of Ph 3 P · I 2 have been studied in detail by electronic, 31 P{ 1 H}‐NMR and Raman spectroscopy as well as conductometric measurements. When 1 : 1 ratios of triphenylphosphane and diiodine are mixed in dichloroethane, the molecular adduct is shown to exist also in solution. On the basis of the overall results, this molecular adduct is best described as a charge‐transfer complex of the donor I − with the acceptor Ph 3 PI + , rather than the charge‐transfer complex of the donor Ph 3 P with the acceptor I 2 or the ionic species [Ph 3 PI]I as previously proposed. When higher diiodine to triphenylphosphane ratios are used, the Ph 3 P · I 2 adduct dissociates to give Ph 3 PI + and I 3 − or I 5 − depending on the diiodine excess. Previously reported solution data, which were ascribed to the ionic form of the adduct, are instead in agreement with hydrolysis products (Ph 3 PO, PH 3 POH + ) of the very reactive adduct, formed in the presence of traces of water.