Chapter 4 - Jacobs University

More documents

Recommendations

Info

<strong>Chapter</strong> 6 U-peroxo-Polyoxometalate 6.4 Results and discussion 6.4.1 Synthesis and structure Polyanion [Li(H 2 O)K 4 (H 2 O) 3 {(UO 2 ) 4 (O 2 ) 4 (H 2 O) 2 } 2 (PO 3 OH) 2 P 6 W 36 O 136 ] 25- (4) was synthesized by reaction of the [H 6 P 4 W 24 O 94 ] 18- (P 4 W 24 ) precursor with UO 2+ 2 ions in a 1:3 ratio in aqueous medium at pH 4.0. The polyanion was crystallized as a mixed potassium-lithium salt in the monoclinic space group P2 1 /n. The compound K 6 Li 19 [Li(H 2 O)K 4 (H 2 O) 3 {(UO 2 ) 4 (O 2 ) 4 (H 2 O) 2 } 2 (PO 3 OH) 2 P 6 W 36 O 136 ]×74H 2 O (4a) has been fully characterized in the solid state by single-crystal XRD, TGA-DSC, IR, and elemental analysis, as well as in solution by 31 P NMR. Interestingly, we were unable to obtain 4 by using P 8 W 48 as the reagent instead of P 4 W 24 . Polyanion 4 is composed of three units of P 2 W 12 fused via the respective caps and two dangling phosphates, which are hanging outside of the polyanion where a fourth unit of P 2 W 12 would be placed in P 8 W 48 (Figure 6.3). In contrast with the various complexes mentioned above, only three “P 2 W 12 “ units combine in 4 to form a gapped ring encircling the central U 8 -peroxo moiety. This is the first time that such a U-shaped “(P 2 W 12 ) 3 ” assembly has been seen. There are also four potassium ions inside the anion, which connect the two independent, neutral [(UO 2 )(O 2 )] 4 units. The third P 2 W 12 unit and two dangling phosphate groups are apparently formed in situ by decomposition of some P 4 W 24 precursor. The cavity of the newly generated polyanion “P 6 W 36 ” is filled by two symmetrical uranium-peroxo clusters. This type of uranium cluster has been seen once before with the 2,3,6,7-tetrahydroxy-9, 10-dimethyl-9, 10-dihydro-9, 10-ethnoanthacene organic ligand, 24 but this is the first report of a uranium-peroxo cluster coordinated with an inorganic nucleophile. 113
<strong>Chapter</strong> 6 U-peroxo-Polyoxometalate Li1 K3 K4 K2 K1 K8 Figure 6.3 Combined polyhedral/ball and stick representations of 4. The side- view (upper) shows the U-shaped “P 6 W 36 ” POM ligand into which the two neutral [(UO 2 )(O 2 )] 4 units are incorporated. The topdown view (lower) from the “open” side of 4 (with the central “P 2 W 12 ” POM fragment in the back removed for clarity) highlights that the two uranyl-peroxo clusters are (i) connected via four potassium ions (K1, K2, K3, K4) and (ii) displaced towards one side of the “P 6 W 36 ” POM. The concave surface of the “outer” [(UO 2 )(O 2 )] 4 unit is capped by the square-pyramidal Li1 whereas the “inner” [(UO 2 )(O 2 )] 4 unit is capped by the seven-coordinate K8. Color code: WO 6 octahedra (red), PO 4 tetrahedra (yellow), uranium (green), phosphorus (yellow), potassium (pink), lithium (blue) and oxygen (red). 114
Page 1 and 2:
Synthesis, Structure and Properties
Page 3 and 4:
"The greatest book of philosophy, w
Page 5 and 6:
system, space group I4/m, unit cell
Page 7 and 8:
Acknowledgements The accomplishment
Page 9 and 10:
teaching, and Professor Maravanji S
Page 11 and 12:
2.1.2 Single crystal X-ray diffract
Page 13 and 14:
5.5 Conclusion…………………
Page 15 and 16:
9.1.6.1 Results and discussion…
Page 17 and 18:
9.3.5 Synthesis of K 12 [Hf 4 (µ 2
Page 19 and 20:
Crespo………………………
Page 21 and 22:
Figure 5.4 ORTEP view of the asymme
Page 23 and 24:
Figure 9.6 31 P NMR of 7a in H 2 O/
Page 25 and 26:
Figure 9.34 TGA spectrum of 17a…
Page 27 and 28:
Figure 9.62 FTIR spectrum of 23a…
Page 29 and 30:
Table 9.6 Crystal data and structur
Page 31 and 32:
Chapter 1 Introduction heteropolyan
Page 33 and 34:
Chapter 1 Introduction 1.3 Structur
Page 35 and 36:
Chapter 1 Introduction C) Keggin a-
Page 37 and 38:
Chapter 1 Introduction shows no suc
Page 39 and 40:
Chapter 1 Introduction α-[P 2 W 18
Page 41 and 42:
Chapter 1 Introduction Figure 1.7 B
Page 43 and 44:
Chapter 1 Introduction [P 2 W 18 O
Page 45 and 46:
Chapter 1 Introduction 1.5.3 Medici
Page 47 and 48:
Chapter 1 Introduction (17) Evans,
Page 49 and 50:
Chapter 1 Introduction (48) Mizuno,
Page 51 and 52:
Chapter 1 Introduction (84) Isabell
Page 53 and 54:
Chapter 2 were block-diagonal least
Page 55 and 56:
Chapter 2 Experimental 2.2.3 Synthe
Page 57 and 58:
Chapter 2 Experimental 2.2.7 Synthe
Page 59 and 60:
Chapter 2 Experimental 2.2.11 Synth
Page 61 and 62:
Chapter 2 Experimental 2.3Reference
Page 63 and 64:
Chapter 3 The Wheel-Shaped Cu 20 in
Page 65 and 66: Chapter 3 The Wheel-Shaped Cu 20 3.
Page 69 and 70: Chapter 3 The Wheel-Shaped Cu 20 Fi
Page 71 and 72: Chapter 3 The Wheel-Shaped Cu 20 Cu
Page 75 and 76: Chapter 3 The Wheel-Shaped Cu 20 20
Page 77 and 78: Chapter 4 16-Iron Metal Center Nano
Page 93 and 94: Chapter 5 Organoruthenium POM Chapt
Page 95 and 96: Chapter 5 Organoruthenium POM 5.2 S
Page 97 and 98: Chapter 5 Organoruthenium POM 5.3 X
Page 99 and 100: Chapter 5 Organoruthenium POM 5.4 R
Page 101 and 102: Chapter 5 Organoruthenium POM The f
Page 103 and 104: Chapter 5 Organoruthenium POM On th
Page 105 and 106: Chapter 5 Organoruthenium POM Figur
Page 107 and 108: Chapter 5 Organoruthenium POM (11)
Page 109 and 110: Chapter 6 U-peroxo-Polyoxometalate
Page 115: Chapter 6 U-peroxo-Polyoxometalate
Page 127 and 128: Chapter 7 Pt-containing Polyoxometa
Page 141 and 142: Chapter 8 Collaborative Work Chapte
Page 143 and 144: Chapter 8 Collaborative Work 8.2.1
Page 145 and 146: Chapter 9 Unpublished Results Figur
Page 147 and 148: Chapter 9 Unpublished Results solid
Page 151 and 152: Chapter 9 Unpublished Results 9.1.3
Page 163 and 164: Chapter 9 Unpublished Results There
Page 167 and 168:
Chapter 9 Unpublished Results 9.1.8
Page 169 and 170:
Page 171 and 172:
Chapter 9 Unpublished Results Figur
Page 173 and 174:
Chapter 9 Unpublished Results Table
Page 175 and 176:
Page 177 and 178:
Page 179 and 180:
Page 181 and 182:
Page 183 and 184:
Page 185 and 186:
Page 187 and 188:
Page 189 and 190:
Page 191 and 192:
Page 193 and 194:
Page 195 and 196:
Page 197 and 198:
Page 199 and 200:
Page 201 and 202:
Chapter 9 Unpublished Results exhib
Page 203 and 204:
Page 205 and 206:
Page 207 and 208:
Page 209 and 210:
Page 211 and 212:
Page 213 and 214:
Page 215 and 216:
Page 217 and 218:
Page 219 and 220:
Chapter 9 Unpublished Results The d
Page 221 and 222:
Page 223 and 224:
Chapter 9 Unpublished Results 23a (
Page 225 and 226:
Page 227 and 228:
Page 229 and 230:
Page 231 and 232:
Page 233 and 234:
Page 235 and 236:
Page 237 and 238:
Curriculum Vitae SIB SANKAR MAL Dep
Page 239 and 240:
EDUCATION PhD Jacobs University (20
Page 241 and 242:
POSTER, ORAL PRESENTATION 1. Poster
Page 243 and 244:
6. “Two Iron-Containing Tungstoge
Page 245 and 246:
Appendix
Page 247 and 248:
Page 249 and 250:
Appendix
Page 251 and 252:
show all

Chapter 4 - Jacobs University

Create successful ePaper yourself

Delete template?

Save as template?