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88 Chapter 4 Figure 4.25. UHV-IR spectra of Ru-DEMOF 1c and 1d compared with parent Ru-MOF and Ru- DEMOF with 30% pydc incorporation upon CO 2 dosing at 90-95 K after annealing the sample at 475-500 K. The bands at 2041 cm -1 and 1993 cm -1 are assigned to vibrations of CO bound to reduced Ru δ+ -sites and indicate dissociative chemisorption of CO 2 . Original figures are provided by M. Kauer. ration (1d). The formation of defect B, namely missing Ru-paddlewheels, is accompanied by lowering the abundance of Ru 2+ and Ru δ+ metal centers in the framework, which
Chapter 4 89 explains the observed changes of the decreased intensity of Ru 2+ and Ru δ+ in the sample 1d. In our earlier report on pydc-doped Ru-DEMOFs, we communicated on the low temperature CO2→CO dissociative chemisorption under UHV conditions in a dark environment, a feature which is not inherent for the parent Ru-MOF. [138] We concluded that the CO2→CO reduction might be triggered by the reduced Ru δ+ -sites and the pyridyl N-sites in the proximity of the modified Ru-centers at the nodes. In order to confirm these assumptions further, we have studied the same reaction at Ru-DEMOFs that feature reduced Ru δ+ -sites. As these sites have been created by the incorporation of the 5-OH-ip linker in 1a-d, we have selected two representative samples, 1c and 1d, both exhibiting high 5-OH-ip incorporation but quite different levels of Ru 2+ and Ru δ+ . As shown in Figure 4.25, upon CO2 dosing for both the parent Ru-MOF and Ru-DEMOFs 1c, an intense and broad IR band appears at 2336 cm -1 that is assigned to the asymmetric stretching mode νas(CO2) of physisorbed CO2 binding linearly at various Ru-sites. [198] The weak band at 2273 cm -1 indicates the presence of a minority CO2 species originating probably from the adsorption of a small amount of 13 CO2 with an expected isotopic shift of 1.03. Apart from the CO2-related bands, two other bands at 2041 cm -1 and 1993 cm -1 have been observed in 1c, that are assigned to vibrations of CO bound to the reduced Ru δ+ -sites, matching our previous data on pydc-doped Ru-DEMOF. [138] This result indicates dissociative chemisorption of CO2 to CO (reduction) in Ru-DEMOF with 5-OH-ip DL (1c), whereas the parent Ru-MOF is essentially inactive. However, in comparison to the extremely high reactivity of pydc-doped Ru-DEMOFs, in which CO2 is nearly totally converted to CO at higher concentrations of pydc defective linker (e.g. 30%), [138] the production of CO is rather limited for 5-OH-ip doped Ru-DEMOFs (Figure 4.25). Interestingly, Ru-DEMOF 1d, is almost inactive for CO2 dissociation. We correlate this observation to the much less Ru δ+ and in turn to the more significant formation of missing node defects (type B) for 1d as compared to 1c. Overall, the presented IR data demonstrate that the 5-OH-ip doped Ru- DEMOF samples show much less reactivity for CO2 activation as compared to pydc doped samples. This cannot be attributed only to the relatively low concentration of reduced Ru δ+ . In previous study it was suggested that the CO2 activation being promoted by pydc linker due to the presence of basic pyridyl N sites in proximity to the reactive Ru δ+ . [138] This hypothesis is indirectly supported by the properties of samples 1c and 1d.
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Controlled Modification of Metal-Or
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This thesis is based on the work pe
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Bochum) for the study of XPS and UH
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Zhang, for their continuous support
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II 3.2.1 Synthesis and characteriza
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IV 7.3.4 Synthesis of Cu-DEMOF samp
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VI DMSO dobdc e.g. EA EDX EtOH EXAF
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VIII TOF UHV UiO UMCM vs WCA XANES
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2 Chapter 1 limitations of the (non
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4 Chapter 2 For the synthesis of CP
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6 Chapter 2 cavities is able to rev
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8 Chapter 2 2.2.2 MOF features Adva
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10 Chapter 2 Figure 2.5. A series o
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12 Chapter 2 the material is retain
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14 Chapter 2 2.3 Synthetic approach
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16 Chapter 2 Expansion of this stru
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18 Chapter 2 (H2BPDC) [75] or other
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20 Chapter 2 Cr III CUSs of MIL-101
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22 Chapter 2 Figure 2.14. Schematic
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24 Chapter 2 adsorbate-surface inte
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3 Controlled secondary building uni
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28 Chapter 3 3.1 Preparation and in
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30 Chapter 3 formula of [Ru3 II,III
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Intensity, a. u. 32 Chapter 3 quali
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34 Chapter 3 After activating the R
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36 Chapter 3 presence of the residu
Page 56 and 57: Intensity, a. u. 38 Chapter 3 the a
Page 58 and 59: 40 Chapter 3 extent than acetic aci
Page 60 and 61: 42 Chapter 3 Ru-nodes. Therefore, r
Page 62 and 63: 44 Chapter 3 decomposition of [BF4]
Page 64 and 65: deriv. normalized E) 46 Chapter 3 F
Page 66 and 67: 48 Chapter 3 3.1.6 Summary Applying
Page 68 and 69: 50 Chapter 3 3.2 Elaboration of Ru
Page 70 and 71: 52 Chapter 3 with that of the Ru II
Page 72 and 73: 54 Chapter 3 Figure 3.20. (a) XANES
Page 74 and 75: 4 Linker-based MOF solid solutions:
Page 76 and 77: 58 Chapter 4 4.1 Introduction 4.1.1
Page 78 and 79: 60 Chapter 4 framework [Cu2(ndc)2(d
Page 80 and 81: 62 Chapter 4 partial replacing of B
Page 82 and 83: 64 Chapter 4 in the case of ip intr
Page 84 and 85: 66 Chapter 4 4.2.1.1 Crystallinity
Page 86 and 87: 68 Chapter 4 suggesting the absence
Page 88 and 89: 70 Chapter 4 Table 4.1. The molar f
Page 90 and 91: 72 Chapter 4 Figure 4.11. IR spectr
Page 92 and 93: 74 Chapter 4 taking into account th
Page 94 and 95: 76 Chapter 4 As quantitative digest
Page 96 and 97: 78 Chapter 4 (Figure 4.16). Notably
Page 98 and 99: 80 Chapter 4 framework Ru-species (
Page 100 and 101: 82 Chapter 4 Figure 4.20. XANES spe
Page 102 and 103: 84 Chapter 4 It is important to not
Page 104 and 105: 86 Chapter 4 Ru δ+ have been obser
Page 108 and 109: 90 Chapter 4 Table 4.5. Possible de
Page 110 and 111: CO 2 adsorbed, mmol/g 92 Chapter 4
Page 112 and 113: H 2 adsorbed, mmol/g 94 Chapter 4 F
Page 114 and 115: CO 2 adsorbed, mmol/g 96 Chapter 4
Page 116 and 117: H 2 adsorbed, mmol/g 98 Chapter 4 8
Page 118 and 119: H 2 adsorbed, mmol/g 100 Chapter 4
Page 120 and 121: 102 Chapter 4 presence of H2. [236]
Page 122 and 123: 104 Chapter 4 reactive metal center
Page 124 and 125: 106 Chapter 4 4.2.6 Conclusions App
Page 126 and 127: 108 Chapter 4 4.3 Defects Engineeri
Page 128 and 129: Intensity, a. u. 110 Chapter 4 as-s
Page 130 and 131: weight loss, % 112 Chapter 4 100 Cu
Page 132 and 133: weight loss, % 114 Chapter 4 record
Page 134 and 135: 116 Chapter 4 4.3.2 Composition and
Page 136 and 137: V, cm 3 /g 118 Chapter 4 500 400 30
Page 138 and 139: 120 Chapter 4 Figure 4.50. From lef
Page 140 and 141: 5 Simultaneous introduction of vari
Page 142 and 143: 124 Chapter 5 preferred like Cu 2+
Page 144 and 145: 126 Chapter 5 5.2 Preparation and S
Page 146 and 147: 128 Chapter 5 Figure 5.5. Pawley Fi
Page 148 and 149: 130 Chapter 5 5.3 Compositional cha
Page 150 and 151: 132 Chapter 5 Table 5.3. The assign
Page 152 and 153: 134 Chapter 5 framework are dominan
Page 154 and 155: 136 Chapter 5 5.4 Synthesis, compos
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138 Chapter 5 obtained Pd-doped sol
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140 Chapter 5 Figure 5.18. Deconvol
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V, cm 3 /g 142 Chapter 5 sorption i
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144 Chapter 5 time as well as the i
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146 Chapter 5 5.6 Conclusions In su
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148 Chapter 6 coordinating anion),
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7 Experimental Section In this Chap
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152 Chapter 7 as water and hydroxyl
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154 Chapter 7 internal standards an
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156 Chapter 7 Uppermost layer is in
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158 Chapter 7 to the more tightly b
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160 Chapter 7 7.2 Experimental data
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162 Chapter 7 [Ru2(OOCC(CH3)3)4(H2O
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164 Chapter 7 Figure 7.7. The PXRD
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166 Chapter 7 [Ru2(OOCCH3)4(H2O)2]B
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168 Chapter 7 [Ru2(OOCCH3)4](THF)2
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170 Chapter 7 [Ru3(BTC)2(OH)1.5]n·
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172 Chapter 7 [Ru3(BTC)2]n∙(AcOH)
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174 Chapter 7 Table 7.3. Feeding mo
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176 Chapter 7 For comparison of the
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178 Chapter 7 7.3.4 Synthesis of Cu
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180 Chapter 7 D3 The mixture of H3B
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182 Chapter 7 D5 This sample was re
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184 Chapter 7 The synthesis of D7 a
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186 Chapter 7 7.4 Experimental data
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188 Chapter 7 Figure 7.26. PXRD pat
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190 Chapter 7 7.4.2 Hydrogenation o
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192 Chapter 7 7.5 Supplementary det
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8 Bibliography [1] A. J. Ihde, The
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196 Bibliography [61] S. Ma, D. Sun
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198 Bibliography [121] T. K. Prasad
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200 Bibliography [180] Y. Kobayashi
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202 Bibliography [239] A. L. Harreu
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204 Bibliography [297] A. P. Hammer
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206 Appendix List of Presentations
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208 Appendix 05. 2015 Grant from th
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