A solution and solid state study of niobium complexes University of ...

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Chapter 4 Figure 4.14: Inter- and intramolecular hydrogen interactions found between the [NbCl(phacac-κ 2 -O,O’)(OMe)3] and [NbCl2(phacac-κ 2 -O,O’)(OMe)2] molecules. Only applicable hydrogen atoms with relevance to hydrogen bond interactions are indicated. Inter- and intramolecular hydrogen bonding are illustrated in Figure 4.14. Intramolecular bonding exists between O1 and H12 (B) with a donor-acceptor (D-A) bond distance of 2.742 (6) Å, while intermolecular bonding occurs between Cl2 and H6A (A) with a D-A distance of 3.611 (8) Å. An intermolecular interaction also exists between Cl1 and H2 (C) with a D-A distance of 3.655 (5) Å. A complete list of hydrogen bonds is given in Table 4.9. 75
Chapter 4 Table 4.9: Hydrogen bonds for [NbCl(phacac-κ 2 -O,O’)(OMe)3] and [NbCl2(phacac-κ 2 - O,O’)(OMe)2]. Interaction D-H···A D-H (Å) H···A (Å) D···A (Å) < D-H···A (°) A C6 k , H6A k , Cl2 l 0.958 (3) 2.809 (6) 3.611 (8) 142.04 (4) B C12 k , H12 k , O1 k 0.933 (4) 2.423 (2) 2.742 (6) 100.10 (3) C C2 k , H2 k , Cl1 m 0.927 (3) 2.768 (4) 3.655 (5) 158.92 (6) Symmetry operations: k [x, y, z]; l [x, 0.5-y, -0.5+z]; m [x, -0.5-y, 0.5+z] Molecular packing within the unit cell (Figure 4.15) shows a “head to tail” arrangement of the [NbCl(phacac-κ 2 -O,O’)(OMe)3] and [NbCl2(phacac-κ 2 - O,O’)(OMe)2] complexes when viewed along the b-axis. Figure 4.15: Complexes of [NbCl(phacac-κ 2 -O,O’)(OMe)3] and [NbCl2(phacac-κ 2 -O,O’) (OMe)2] displaying a sheet-like “head to tail” crystal packing along the b-axis. Hydrogen atoms have been omitted for clarity. Displacement ellipsoids are drawn at the 50% probability displacement level. The largest differential peak was 2.616 e.Å -3 , 0.93 Å from Nb1 and the deepest hole -1.761 e.Å -3 , 0.80 Å from Nb1. 76
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A solution and solid state study of
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Table of contents Abbreviations and
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3.4 Infrared Spectroscopy (IR) ....
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Abbreviations and Symbols Abbreviat
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Abstract 93 Nb NMR was successfully
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Opsomming 93 Nb KMR is met sukses g
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Chapter 1 metals. 3 Due to Wollasto
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Synopsis... 2. Literature Review of
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Chapter 2 Niobium resembles tantalu
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2.1.2 Uses Chapter 2 Niobium has a
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2.2 Separation of Nb and Ta 2.2.1 M
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Chapter 2 Buachuang et al. 16 repor
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Chapter 2 Niobium oxide surfaces ex
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2.4.6 Water absorption Chapter 2 Th
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Chapter 2 been reported in literatu
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Chapter 2 containing niobium as the
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Chapter 2 conclusions, with regard
Page 35 and 36: Chapter 2 Figure 2.5: Structure of
Page 37 and 38: 2.6.3.3 [NbCl3O(ttbd) - ] Chapter 2
Page 39 and 40: Chapter 2 (a) (b) Figure 2.10: Stru
Page 41 and 42: 2.7 Alkoxides Chapter 2 Specific kn
Page 43 and 44: Chapter 2 Reactions of dialkylamid
Page 45 and 46: Chapter 2 other NbCl5-x(OMe)x produ
Page 47 and 48: Chapter 2 In 1991 Lee et al. 83 pub
Page 49 and 50: EtO EtO EtO EtO Cl Nb Cl Cl Nb Cl R
Page 51 and 52: Chapter 2 The hemicarbonate formed
Page 53 and 54: Synopsis... 3. Synthesis and Charac
Page 55 and 56: Chapter 3 with γ = magnetogyric ra
Page 57 and 58: Chapter 3 electromagnetic spectrum
Page 59 and 60: 3.5.1 Bragg’s law Chapter 3 Bragg
Page 61 and 62: 3.5.3 ‘Phase problem’ Chapter 3
Page 63 and 64: Chapter 3 A = ∑ ε cl (3.14) In
Page 65 and 66: Chapter 3 t1/2 = 54 = . 3.7 Sy
Page 67 and 68: 3.7.2.4 Synthesis of [NbCl4(acac)]:
Page 69 and 70: 4. Crystallographic Synopsis... Cha
Page 71 and 72: Chapter 4 packages 2 respectively.
Page 73 and 74: Chapter 4 4.3 Crystal Structure of
Page 75 and 76: Chapter 4 longer bonds (C1-C2, C2-C
Page 77 and 78: Chapter 4 Figure 4.5: Packing of [N
Page 79 and 80: Chapter 4 Figure 4.7: Molecular str
Page 81 and 82: Chapter 4 Table 4.5: Selected bond
Page 83 and 84: Chapter 4 Figure 4.11: Molecular st
Page 85: Chapter 4 Figure 4.12: The phacac p
Page 89 and 90: Chapter 4 According to our knowledg
Page 91 and 92: 5.2 Experimental procedures 5.2.1 K
Page 93 and 94: Chapter 5 corresponds to one specie
Page 95 and 96: 5.3 Results and Discussion 5.3.1 Pr
Page 97 and 98: Chapter 5 Figure 5.5: Typical UV/Vi
Page 99 and 100: 5.3.3 Derivation of the rate law Ch
Page 101 and 102: Chapter 5 The Stopped-flow data (fa
Page 103 and 104: Chapter 5 Figure 5.9: Eyring plot,
Page 105 and 106: Chapter 5 However, more information
Page 107 and 108: Chapter 6 second reaction entailed
Page 109 and 110: Appendix A Table 1.3: Bond angles (
Page 111 and 112: Appendix A A 2 Supplementary Data f
Page 113 and 114: Appendix A C(16)-H(16B) 0.96 C(16)-
Page 115 and 116: Appendix A O(7)-C(10)-C(11) 123.6 (
Page 117 and 118: Appendix A H(18E)-C(18B)-H(18F) 109
Page 119 and 120: Appendix A H(18F) 6243 6605 575 75
Page 121 and 122: Appendix A Table 3.3: Bond angles (
Page 123 and 124: Appendix A Table 3.4: Anisotropic d
Page 125: Appendix B Appendix B B 1 Supplemen
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A solution and solid state study of niobium complexes University of ...

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