Supplementary Material (ESI) for Chemical Communications
This journal is © The Royal Society of Chemistry 200
Experimental details
This station is equipped with Si(220) monochromator, ion chambers for measuring
incident and transmitted beam intensities and Canberra fluorescence detector and a INEL
position sensitive detector to record XRD data. In a typical experiment 40 mg of
MnAlPO-18 catalyst, in a pellet form, was loaded into the in situ cell and data were
collected during the heating in air from room temperature to 550oC at 5oC/min. XAS
data were processed using the suite of programs, EXCALIB, EXBROOK and
EXCURV98. Both EXAFS data analysis and simulation of EXAFS data were carried out
using multiple-scattering procedures. Here, in this procedure, we constructed a starting
model using the coordinates obtained from the quantum chemical calculations and used
C1 symmettry for the multiple scattering calculations. In the refinement, since the Mn-O
distances are closely similar, we have constrained to be the same value. Similarly, the
Debye-Waller factors for the same type of back scattering atoms are maintained equal.
Mn-P distances and the Mn-O-P bond angles were refined independently. More details
of the general procedure is given elsewhere1
1
D. Gleeson, G. Sankar, C. R. A. Catlow, J. M. Thomas, G. Spano, S. Bordiga, A.
Zecchina, and C. Lamberti, Physical Chemistry Chemical Physics, 2000, 2, 4812
Table : The structural parameters obtained for calcined MnAlPO-18 catalyst from the
EXAFS data analysis using multiple scattering procedure, taking quantum mechanically
derived structure as the starting point.
Mn-O distance
(Å)
Mn-P distance
(Å)
Mn-O-P Bond
Angle (degrees)
1.85
1.85
1.85
1.85
3.22
3.31
3.13
3.13
148
161
136
138
Mn-O
Debye-Waller
Factor (Å2)
0.005
0.005
0.005
0.005
Mn-P
Debye-Waller
Factor (Å2)
0.007
0.007
0.007
0.007
6
(a)
(b)
25
4
20
FT Magnitude
0
3
k  (k)
2
15
10
-2
5
-4
0
-6
2
4
6
8
k /Å
-1
10
12
0
1
2
3
4
5
6
R/Å
Fig. S1: Comparison of the (a) Mn K-edge experimental EXAFS data (solid line) with the
one simulated (employing full multiple scattering method available in the EXCURV
program) using the structure determined by the quantum mechanical method for the highspin Mn(III) ion (dashed line). Note that the frequencies of the simulated EXAFS data
match well the experimental one (also seen in the first peak of the FT, shown in (b)).
25
FT Magnitude
20
15
10
5
0
0
1
2
3
4
5
6
R/Å
Fig. S2: Fourier transform of the experimental EXAFS data (solid line) and the calculated
EXAFS (dashed curve) obtained from the best fit, shown in figure 2.