High- and Low-spin Complexes with Similar Ligands. Iron(II) Complexes of Terpyridyl and Its Derivatives
Two new ligands, 2,6-di(2′-quinolyl)pyridine (dqp) and 2-acetyl-6-(2′-quinolyl)pyridine (aqp), have been prepared by the reaction of pyridine-2,6-diacetyl and o-aminobenzaldehyde. dqp is a benzo-disubstituted analog of 2,2′,2′-terpyridyl (terpy), but its bis-chelated ferrous complex is high spin, whereas that of terpy is low spin. This observation and the electronic spectra indicate that dqp is a much weaker ligand (Δ ∼ 12,000 cm -1) than terpy. These results are interpreted in terms of an increase in the average metal-ligand bond distance as a result of the steric effect of benzo substitution. The bis-chelated ferrous complex of aqp is high spin, as expected.
C. M. Harris et al., "High- and Low-spin Complexes with Similar Ligands. Iron(II) Complexes of Terpyridyl and Its Derivatives," Inorganic Chemistry, American Chemical Society (ACS), Jan 1969.
The definitive version is available at http://dx.doi.org/10.1021/ic50071a024
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© 1969 American Chemical Society (ACS), All rights reserved.