
%0 Journal Article
%A Singh, PR 
%A Sahai, R 
%T Chemical and spectroscopic studies in metal &#946;-diketonates. VIII. Electronic spectral studies on some trivalent 3d metal diketonates and their &#947;-substituted derivatives
%J Australian Journal of Chemistry
%D 1969/06/01
%V 22
%N 6
%P 1169-1175
%K 
%R https://doi.org/10.1071/CH9691169
%U https://www.publish.csiro.au/paper/CH9691169 
%X Electronic absorption spectra of solutions of chromium(III), iron(III), and cobalt(III) &#946;-diketonates have been measured in the 200- 1200m&#956; region. Detailed interpretation of the spectral data are provided in terms of the &#960;g &#8594; &#960;4, the electron transfer (d&#949; &#8594; &#960;4), and the ligand field (d &#8594; d*) transitions of the various components. The effects of &#947;-substituents on the chelate rings upon the positions of different transitions are discussed. Substitution of a halogen results in bathochromic shift in &#960;3 &#8594; &#960;4, d&#949; &#8594; &#960;4, and d &#8594; d* transitions of each chelate, presumably due to extension of conjugation, interaction among d&#949; and &#960;3 orbitals (which raises d&#949; orbitals to a higher energy), and decrease in ligand field effect respectively. The hypsochromic shifts observed in the cases of NO2, SCN, Ac, and CHO &#947;-substituents are perhaps due to the steric inhibition of resonance with the chelate ring. 
