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Fig. 1.6: Ball and stick representation of the Lindqvist structure that the metals occupy equivalent octahedral sites, so that they make one short terminal M-O bond and a rather long M-O bond to the translocated high-coordinate oxygen site. This cluster is known as the Lindqvist type structure, e.g. [M 6 O 19 ] n− (n= 8 for M= Nb, Ta) and (n = 2 for M= Mo, W ). In Figure 1.7, the polyanion is based on an Fig. 1.7: Polyhedron representation of the Anderson structure arrangement of seven edge shared octahedra where the heteroatom “X” is surrounded by six-oxo ligands in a pseudo-octahedral symmetry and it occupies the central position. 9
This planar structure was originally proposed by Anderson for the heptamolybdate anion, [Mo 7 O 24 ] 6− , but it was observed for the first time when Evans reported the structure of [TeMo 6 O 24 ] 6− , which was isostructural to that of the 6-molybdo-anion [IMo 6 O 24 ] 5− , It is generally know as ‘Anderson-Evans’ structure [31]. In Figure 1.8, the complete anion Fig. 1.8: Ball and stick representation of the Wells-Dawson structure consist of two identical ‘half-units’ related by a plane of symmetry perpendicular to the trigonal axis. The ‘half-units’ are linked together by six oxygen atoms situated in the plane of symmetry, so that these atoms are shared equally by the two halves. The two heteroatoms ‘X’ are tetrahedrally coordinated and surrounded by nine WO 6 octahedra linked together by edge sharing and corner sharing. This type of cluster is generally known as ‘Wells-Dawson structure’ [32]. 1.3 Lacunary Species Although all polyoxoanions are ultimately decomposed to monomeric species in basic solution, controlling the pH can lead to the formation and isolation of ‘defect’ or ‘lacunary’ structures. These are best illustrated with the α isomers of the Keggin-type polyanion, the Keggin anion has five different rotational isomers known as ‘Baker-Figgis’(α,β,γ,δ,ɛ). 10
Page 1 and 2: Hybrid Organic-Inorganic Polyoxomet
Page 3 and 4: Abstract Polyoxometalates (POMs) ar
Page 5 and 6: the cubic system (space group I m¯
Page 7 and 8: AsW 9 O 32 OH) 2 ]·36H 2 O (RbNa-1
Page 9 and 10: Paris-Sud, Orsay Cedex, France) for
Page 11 and 12: 2.2.9 Synthesis of K 12 [H 2 P 2 W
Page 13 and 14: Bibliography . . . . . . . . . . .
Page 15 and 16: 3.5 Left: combined polyhedral and b
Page 17 and 18: 3.33 Combined polyhedron and ball/s
Page 19 and 20: List of Tables 1.1 Selected M-M dis
Page 21 and 22: MO 6 octahedra surrounding a centra
Page 23 and 24: 1.1.1 The clathrate-like structure
Page 25 and 26: 7(MoO 4 ) 2− + 8H + → [Mo 7 O 2
Page 27: Fig. 1.4: Combined polyhedral/ball
Page 31 and 32: [X 2 M 18 O 62 ] 6− , the D 3h We
Page 33 and 34: [P 2 W 19 O 68 (HO)] 14− , [P 2 W
Page 35 and 36: Fig. 1.11: Monomeric (left) and dim
Page 37 and 38: Chapter 2 Experimental 2.0.1 Reagen
Page 39 and 40: 2.2 Preparation of starting materia
Page 41 and 42: as Cs 6 [P 2 W 5 O 23 ]·7H 2 O by
Page 43 and 44: was adjusted between 5-6 by additio
Page 45 and 46: Chapter 3 Results 3.1 The hybrid or
Page 47 and 48: Fig. 3.2: FTIR spectra of compound
Page 49 and 50: Fig. 3.3: W 183 NMR spectra of (CsN
Page 51 and 52: Fig. 3.5: Left: combined polyhedral
Page 53 and 54: formed upon crystallization and bot
Page 55 and 56: X-ray Crystallography A crystal of
Page 57 and 58: the presence of the four (CH 3 ) 2
Page 59 and 60: Fig. 3.10: Cyclic voltammogram of 2
Page 61 and 62: as a function of electrolyte compos
Page 63 and 64: was observed that could be traced t
Page 65 and 66: electrochemical set-up was an EG &
Page 67 and 68: Fig. 3.14: The central core of Sn(C
Page 69 and 70: of these fragments [88, 90]. For co
Page 71 and 72: diffractometer using Mo K α radiat
Page 73 and 74: Fig. 3.18: Side view of [{Sn(CH 3 )
Page 75 and 76: host−guest systems with large cav
Page 77 and 78: X-ray Crystallography Single crysta
Page 79 and 80:
3.5.2 Results and discussions Polya
Page 81 and 82:
Fig. 3.26: Ball and stick represent
Page 83 and 84:
can distinguish between different m
Page 85 and 86:
Fig. 3.28: STM pictures of {Sn(CH 3
Page 87 and 88:
Fig. 3.31: Size distribution by int
Page 89 and 90:
3.6 The bis-phenyltin substituted,
Page 91 and 92:
Table 3.7: Crystal Data and Structu
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tral belt in-between the two tin at
Page 95 and 96:
Fig. 3.35: 183 W NMR spectra of com
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whereas they are five-coordinated (
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investigated by scanning tunneling
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3.8 The di-titanium substituted, lo
Page 103 and 104:
Fig. 3.37: Ball/stick (left), polyh
Page 105 and 106:
[As 2 W 19 O 67 (H 2 O)] 14− , [A
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3.9 The cyclic trimeric-titanium su
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Table 3.9: Crystal Data and Structu
Page 111 and 112:
Fig. 3.40: FTIR spectra of compound
Page 113 and 114:
Fig. 3.42: Side-view of compound 11
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11 by 183 W-NMR (at 16.66 MHz on a
Page 117 and 118:
3.11 Structure and solution propert
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472(w), 444(w) cm −1 . This proce
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MHz in 10 mm tubes and the 111 Cd N
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Fig. 3.47: 111 Cd NMR spectra of [C
Page 125 and 126:
in aqueous solution, so that the nu
Page 127 and 128:
of cadmium ions in 12 and 13 and it
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doubtedly 183 W-NMR, but the parama
Page 131 and 132:
K): (relative intensities in parent
Page 133 and 134:
Fig. 3.49: Combined polyhedral/ball
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Fig. 3.50: 183 W NMR spectrum of [I
Page 137 and 138:
(17) are isostructural. They consis
Page 139 and 140:
Fig. 3.53: 183 W NMR spectrum of [I
Page 141 and 142:
3.12.4 Conclusion We have synthesiz
Page 143 and 144:
[37] D. Gatteschi, O. Kahn, J. Mill
Page 145 and 146:
94:226403, 2005. [123] R. J. Hamers
Page 147 and 148:
[206] I. Loose, E. Droste, M. Bösi
Page 149 and 150:
NMR Spectra Fig. 3.54: 13 C NMR spe
Page 151 and 152:
Fig. 3.56: 31 P NMR spectrum of pol
Page 153 and 154:
Fig. 3.58: 13 C NMR spectrum of pol
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Fig. 3.60: 1 H NMR spectrum of poly
Page 157 and 158:
Fig. 3.62: 119 Sn NMR spectrum of p
Page 159 and 160:
Fig. 3.66: 1 H NMR spectrum of poly
Page 161 and 162:
Fig. 3.70: 13 C NMR spectrum of pol
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were applied and an absorption corr
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Fig. 3.75: Size distribution by num
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Table 3.16: Crystal Data and Struct
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Fig. 3.80: FTIR spectra of compound
Page 171 and 172:
FIRASAT HUSSAIN International Unive
Page 173 and 174:
Publications 1. Observation of a Ha
Page 175 and 176:
PAPERS IN CONFERENCE/ SYMPOSIA / WO
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