5.14.3 Interaction with Carbon Monoxide
Among Co ϒAl 2 O 3 Rh ϒAl 2 O 3 RhZrO 2 , only Rh ϒAl 2 O 3 shows a Rh-CO adduct
(Fig. 5.13).
The spectrum in Fig. 5.13, due to the wideness of lines, indicates the unpaired
electron on the Rh centers; nevertheless, the small displacement from the free
electron value and the absence of magnetic anisotropy suggest that the interaction
with CO removes part of the unpaired electron from the metal center.
(a)
(b)
(c)
(d)
(e)
Fig. 5.12 X band ESR
spectra recorded at −150 °C
of a ZrO 2 , b Rh ZrO 2
recorded under O 2 (10 Pa
pressure), c Rh ϒAl 2 O 3
recorded under O 2 (10 Pa
pressure), d Rh ZrO 2
recorded under O 2 (10 Pa
pressure) and CO (10 Pa
pressure), e Co ϒAl 2 O 3
recorded under O 2 (10 Pa
pressure) [12]
100
5 The Symmetry Properties Describe the Electronic Structure …