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86 Chapter 4
Ru δ+ have been observed in the XP spectra (no Ru3d doublets at ca. 280.5 and 284.7 eV;
Figure 4.23). These data confirm the assignment deduced from XANES data, suggesting
that application of DL with the coordinatively inactive functional group H (2a-b) is likely
to more selectively induce missing node defects B in the Ru-DEMOFs without Ru
reduction (as this is indicative for a type A defect). According to the results of XANES and
XPS, we thus conclude that the Ru-DEMOFs materials with 5-X-ip (X= OH, NH2 and Br)
contain predominantly defects A, especially at moderate incorporation levels. However,
the simultaneous generation of defects B in these samples is also likely as indirectly
deduced from the non-linear dependence of the XANES and XPS data on the doping level.
Table 4.4. The assignments of binding energies as well as the ratio of Ru 3+ / Ru 2+ / Ru δ+ (calculated
from the deconvoluted spectra) in the parent Ru-MOF sample and Ru-DEMOFs (1a, 1c 1d, 2a and
2b). 1a, 1c and 1d - 8%, 32% and 37% of 5-OH-ip, respectively; 2a and 2b - 15% and 28% of ip,
respectively. Data provided by P. Guo.
Sample Binding energy, eV Assignment Ru 3+ / Ru 2+ / Ru δ+ ratio
Parent Ru-MOF
1a
1c
1d
2a
285.86 / 281.66 Ru 2+
286.86 / 282.66 Ru 3+
285.86 / 281.66 Ru 2+
286.86 / 282.66 Ru 3+
284.65 / 280.45 Ru δ+
285.71 /281.51 Ru 2+
286.71 / 282.60 Ru 3+
284.60 / 280.40 Ru δ+
285.72 / 281.52 Ru 2+
286.72 / 282.52 Ru 3+
284.65 / 280.45 Ru δ+
285.86 /281.66 Ru 2+
286.86 / 282.66 Ru 3+
1 / 1.24 / -*
1 / 1.75 / 0.08
1 / 1.69 / 0.59
1 / 1.23 / 0.09
1 / 1.73/ -*
285.88 / 281.68 Ru 2+
2b
286.88 / 282.76 Ru 3+
* no species have been determined.
1 / 1.42 / -*
Consequently, UHV-IR spectroscopic investigations employing CO as a probe molecule
have been carried out on two representative samples 1c and 1d to gain complementary