Synthesis and Structural Characterization of ... - Jacobs University

More documents

Recommendations

Info

Chapter 1 Introduction Isopolyanions are represented by the general formula [M m O y ] n− , where M is the addendum; usually molybdenum or tungsten, less frequently vanadium, niobium or tantalum in high oxidation states. 1a However, recently it was shown that palladium(II) and gold(III) can act as addenda as well. 12 Heteropolyanions are represented with the general formula [X x M m O y ] q− (x m) where X, the heteroatom (hence the terminology “hereropoly”), can be one of many elements of the periodic table, most commonly P 5+ , As 5+ , Si 4+ , Ge 4+ and B 3+ . Furthermore, there is no restriction on the heteroatom, X, and can be either tetrahedrally coordinated (as in the Keggin structure) or octahedrally coordinated (as in the Anderson-Evans structure). In the latter capacity are found more than sixty-five elements from all groups of the periodic table (except the rare gases). However, the metallic elements that can function as addenda atoms are limited to those with both a favorable combination of ionic radius and charge (charge/radius ratio), and the ability of empty d-orbitals to form π M-O bonds via dπ-pπ overlaping. POMs can be mixed, where the addenda positions can be occupied by two or more elements (e.g. Mo/V, W/V), or non-mixed, where M is exclusively one metal. 1a 1.2.1 Structural units There is an enormous molecular diversity of POMs and many reports, books and reviews have been published about this inorganic family of molecules. 1 POMs can be regarded as packed arrays of pyramidal MO 5 and octahedral MO 6 units (building blocks) and these entities can be considered as similar as the –CH 2 – in organic chemistry. These MO n units can be packed to form different shapes, but there are some simple rules for them to join one another in order to build the POM frameworks. The molecules as a whole are built by edge- and/or cornersharing MO n polyhedra, and very rare by face-sharing (Figure 1.1). The most stable linkages are the edge- and corner-sharing models (A and B in Figure 1.1), in which the M n+ ions are far enough from each other in order to decrease the columbic repulsion between them (Table 1.1). In the case of the face-sharing contact (C in Figure 1.1) the metallic centers are closer than in 3
Chapter 1 Introduction A or B. At such distances the repulsion is not balanced by the stabilization due to the chemical bonding. Nevertheless, Linking of MO 6 octahedra by face-sharing was first reported by Dexter and Silverton in 1968 presented the structure of [CeMo 12 O 42 ] 8– . 13 This species consists of six pairs of face-shared octahedra (Mo 2 O 9 unit) resulting in icosahedral geometry. The molybdenum atom positions with mean Mo…Mo separations of 3.18 and 3.84 Å (faceand corner-shared contacts respectively). 1a A B C Figure 1.1 Polyhedral models that represent the possible linkages between two MO 6 octahedral units. A) corner-sharing, B) edge-sharing and C) face-sharing. Each corner represents an oxygen position. Table 1.1. M … M distances (Å) of corner- and edge- sharing octahedra in POMs. Metal Ion corner- sharing edge- sharing W(VI) 3.70 3.41 Mo(VI) 3.70 3.41 V(V) 3.50 3.20 1.2.2 Some common structures Some common structural types of isopoly- and heteropolyanions are depicted in Figure 1.2 and 1.3: 1 4
Page 1 and 2: Synthesis and Structural Characteri
Page 3 and 4: Amal H. Ismail Ph.D. Thesis Acknowl
Page 5 and 6: Amal H. Ismail Ph.D. Thesis Abstrac
Page 7 and 8: Amal H. Ismail Ph.D. Thesis 1.6.1 P
Page 9 and 10: Amal H. Ismail Ph.D. Thesis 3.B.1.2
Page 11 and 12: Amal H. Ismail Ph.D. Thesis 5.B.2.
Page 13 and 14: Amal H. Ismail Ph.D. Thesis Figure
Page 15 and 16: Amal H. Ismail Ph.D. Thesis (pink);
Page 21 and 22: Amal H. Ismail Ph.D. Thesis List of
Page 23 and 24: Amal H. Ismail Ph.D. Thesis K 8 Cs
Page 25: Chapter 1 Introduction proposed a s
Page 29 and 30: Chapter 1 Introduction c) [(H 2 )W
Page 31 and 32: Chapter 1 Introduction by protonati
Page 33 and 34: Chapter 1 Introduction structures;
Page 35 and 36: Chapter 1 Introduction mono-, di-,
Page 37 and 38: Chapter 1 Introduction Removal of t
Page 39 and 40: Chapter 1 Introduction α-[P 2 W 18
Page 41 and 42: Chapter 1 Introduction Figure 1.10
Page 43 and 44: Chapter 1 Introduction In general,
Page 45 and 46: Chapter 1 Introduction 1.6.1 Photoc
Page 47 and 48: Chapter 1 Introduction dioxygen is
Page 49 and 50: Chapter 1 Introduction 1.7 Lanthani
Page 51 and 52: Chapter 1 Introduction ligand for o
Page 53 and 54: Chapter 1 Introduction [Gd 8 As 12
Page 55 and 56: Chapter 1 Introduction Recently, we
Page 57 and 58: Chapter 1 Introduction P 2 W 16 O 5
Page 59 and 60: Chapter 1 Introduction [7] L. C. Pa
Page 61 and 62: Chapter 1 Introduction Malacria, C.
Page 63 and 64: Chapter 1 Introduction [55] B. Nohr
Page 65 and 66: Chapter 2 Experimental 2.2 Instrume
Page 67 and 68: Chapter 2 Experimental 2.3.2 Synthe
Page 69 and 70: Chapter 2 Experimental 2.3.8 Synthe
Page 71 and 72: Chapter 2 Experimental 2.4 Referenc
Page 73 and 74: Chapter 3 Published Results general
Page 75 and 76: Chapter 3 Published Results 2.5 mL
Page 77 and 78:
Chapter 3 Published Results Na 8 [T
Page 79 and 80:
Chapter 3 Published Results matrix
Page 81 and 82:
Chapter 3 Published Results 3.A.1.4
Page 83 and 84:
Chapter 3 Published Results [H 2 W
Page 85 and 86:
Chapter 3 Published Results and one
Page 87 and 88:
Chapter 3 Published Results {W 4 }
Page 89 and 90:
Chapter 3 Published Results We also
Page 91 and 92:
Chapter 3 Published Results Figure
Page 93 and 94:
Chapter 3 Published Results We trie
Page 95 and 96:
Chapter 3 Published Results M. T. P
Page 97 and 98:
Chapter 3 Published Results 72.936(
Page 99 and 100:
Chapter 3 Published Results La, Ce,
Page 101 and 102:
Chapter 3 Published Results Na 8 Eu
Page 103 and 104:
Chapter 3 Published Results Table 3
Page 105 and 106:
Page 107 and 108:
Chapter 3 Published Results Polyani
Page 109 and 110:
Chapter 3 Published Results [LnW 10
Page 111 and 112:
Chapter 3 Published Results analogu
Page 113 and 114:
Chapter 3 Published Results We also
Page 115 and 116:
Chapter 3 Published Results example
Page 117 and 118:
Chapter 3 Published Results 1737; q
Page 119 and 120:
Chapter 3 Published Results 3.B. La
Page 121 and 122:
Chapter 3 Published Results expecte
Page 123 and 124:
Chapter 3 Published Results 3.B.1.3
Page 125 and 126:
Page 127 and 128:
Chapter 3 Published Results differe
Page 129 and 130:
Page 131 and 132:
Page 133 and 134:
Chapter 3 Published Results Acta 20
Page 135 and 136:
Chapter 3 Published Results Chem.,
Page 137 and 138:
Chapter 3 Unpublished Results bond
Page 139 and 140:
Chapter 3 Unpublished Results lanth
Page 141 and 142:
Chapter 3 Unpublished Results Na 10
Page 143 and 144:
Chapter 3 Unpublished Results Figur
Page 145 and 146:
Chapter 3 Unpublished Results 3.B.2
Page 147 and 148:
Chapter 3 Unpublished Results In po
Page 149 and 150:
Page 151 and 152:
Page 153 and 154:
Chapter 3 Unpublished Results (a) (
Page 155 and 156:
Chapter 3 Unpublished Results param
Page 157 and 158:
Chapter 3 Unpublished Results G.-F.
Page 159 and 160:
Chapter 3 Unpublished Results Here
Page 161 and 162:
Page 163 and 164:
Chapter 3 Unpublished Results This
Page 165 and 166:
Chapter 3 Unpublished Results techn
Page 167 and 168:
Page 169 and 170:
Chapter 4 Unpublished Results Chapt
Page 171 and 172:
Chapter 4 Unpublished Results The c
Page 173 and 174:
Chapter 4 Unpublished Results iron(
Page 175 and 176:
Chapter 4 Unpublished Results 4.4.
Page 177 and 178:
Page 179 and 180:
Page 181 and 182:
Chapter 4 Unpublished Results Therm
Page 183 and 184:
Chapter 4 Unpublished Results This
Page 185 and 186:
Chapter 4 Unpublished Results 4.6.
Page 187 and 188:
Chapter 4 Unpublished Results S. Ba
Page 189 and 190:
Chapter 5 Published Results Also te
Page 191 and 192:
Chapter 5 Published Results 5.A.1.3
Page 193 and 194:
Chapter 5 Published Results Table 5
Page 195 and 196:
Chapter 5 Published Results [HTe 2
Page 197 and 198:
Chapter 5 Published Results face-sh
Page 199 and 200:
Chapter 5 Published Results polymol
Page 201 and 202:
Chapter 5 Published Results Each of
Page 203 and 204:
Chapter 5 Published Results Althoug
Page 205 and 206:
Chapter 5 Published Results Polyako
Page 207 and 208:
Chapter 5 Unpublished Results 5.A.2
Page 209 and 210:
Chapter 5 Unpublished Results 610(m
Page 211 and 212:
Chapter 5 Unpublished Results 5.A.2
Page 213 and 214:
Page 215 and 216:
Chapter 5 Unpublished Results {Mo 6
Page 217 and 218:
Chapter 5 Unpublished Results compo
Page 219 and 220:
Chapter 5 Unpublished Results [3] a
Page 221 and 222:
Chapter 5 Published Results 5.B. Tr
Page 223 and 224:
Chapter 5 Published Results H 2 O)
Page 225 and 226:
Chapter 5 Published Results 5.B.3.
Page 227 and 228:
Chapter 5 Published Results Each Ke
Page 229 and 230:
Chapter 5 Published Results GeW 9 O
Page 231 and 232:
Chapter 5 Published Results the axi
Page 233 and 234:
Chapter 5 Published Results The man
Page 235 and 236:
Chapter 5 Published Results 5.B.6.
Page 237 and 238:
Chapter 5 Published Results [19] L.
Page 239:
Amal H. Ismail Ph.D. Thesis Appendi
show all

Synthesis and Structural Characterization of ... - Jacobs University

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?