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NMR Investigations of Restricted Rotations and Metallotropic Shifts in Rhenium(I) Tricarbonyl Halide Complexes of Pyridyl Carboxamide and Thioamide Ligands
Author(s) -
Orrell Keith G.,
Osborne Anthony G.,
Prince Jade O.,
Šik Vladimir,
Vellianitis Dionyssios K.
Publication year - 2000
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/(sici)1099-0682(200002)2000:2<383::aid-ejic383>3.0.co;2-6
Subject(s) - thioamide , chemistry , rhenium , carboxamide , halide , ligand (biochemistry) , medicinal chemistry , stereochemistry , sulfur , coordination complex , crystallography , metal , inorganic chemistry , organic chemistry , biochemistry , receptor
A series of rhenium(I) tricarbonyl halide complexes of pyridyl mono‐ and di‐carboxamides and ‐thioamides has been studied by dynamic NMR techniques. Oxygen coordination to Re I of the carboxamide ligand reduced the energy barrier to C–N rotation by 2–13 kJ mol –1 whereas sulfur–Re I coordination of the thioamide ligands led to a reduction of 28–33 kJ mol –1 . In the pyridyl dicarboxamide and ‐dithioamide metal chelate complexes metallotropic shifts occur between the three donor atoms, O, N, O or S, N, S, energies [Δ G ‡ (298.15 K)] being in the range 78–89 kJ mol –1 ; these high values arise from the strong electron donating properties of the ‐NR 2 (R = Me, Et) groups.