1,2,3-Dithiazolyl and 1,2,35-Dithiadiazolyl Radicals as Spin-Bearing ...

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16a) which has a slightly larger distance at 3.48 Å. 75 While quite a bit longer than the average, this intermolecular separation is still within the sum of the van der Waals radii of two sulfur atoms. Interestingly this compound exhibits some paramagnetism at room temperature although with a value which is only consistent with 30% unpaired spins and the susceptibility drops off rapidly with temperature and is completely diamagnetic at 200 K. Similarly a difluorinated radical I-16b was found to have an intermolecular S-S contact of 3.54 Å. This compound was originally reported to not form dimers, but a regular π-stacked motif along the [001] direction, with the same distance repeated between each radical unit. 76 The magnetic susceptibility however revealed that this compound was diamagnetic across the entire temperature regime investigated and it was later determined that it actually existed in a superlattice and that there were in fact superimposed π-stacked dimers clustered around a 4-fold screw axis in a pin-wheel type arrangement. 77 I-16a I-16b Several attempts have been made to prevent dimerization by introducing a cationic component into the radical framework, in the hopes that the coulombic repulsion would 24
e enough to overcome the energetically favourable propensity for dimerization. Radical I-16c was isolated in 1995 and exhibited a room temperature magnetic moment consistent with one unpaired electron. As the sample was cooled, the susceptibility showed a broad maximum at 275 K which implied the onset of short-range antiferromagnetic ordering. Upon further cooling, the susceptibility continued to decrease slowly until the compound underwent an abrupt transition to a diamagnetic state at 15 K, which has been attributed to a phase transition to diamagnetic dimers. 78 A similar radical cation, I-16d was found to exist as dimers in the solid state giving rise to a very strong antiferromagnetic interaction. 79 However an increase in the susceptibility above 300 K indicated that the antiferromagnetic interactions were not as strong as that which had been observed in the neutral diradical I-16e 80 . The 1,3,2,4-DTDA moiety does not isomerize to its 1,2,3,5-DTDA counterpart due to the fact that the dimers that are formed have the 1,2,3,5 ring above the 1,3,2,4 ring and vice versa such that the mechanism outlined in Figure 1-7 is not possible. I-16c I-16d 25
Page 1 and 2:
1,2,3-Dithiazolyl and 1,2,35-Dithia
Page 3 and 4: an individual binuclear coordinatio
Page 5 and 6: weren’t sure about something our
Page 7 and 8: 2.1 General........................
Page 9 and 10: 5.3 Reverse oDTANQ.................
Page 11 and 12: LIST OF FIGURES AND SCHEMES Figure
Page 13 and 14: Figure 2-12. Magnetic susceptibilit
Page 15 and 16: GLOSSARY OF ABBREVIATIONS ° Degree
Page 17 and 18: K k k B LMCT ls LUMO Kelvin Exchang
Page 19 and 20: LIST OF STRUCTURES I-1 I-2 I-3 I-4
Page 21 and 22: I-16a I-16b I-16c I-16d I-16e I-16f
Page 23 and 24: I-22 I-23 I-24 I-25 exo I-26 endo x
Page 25 and 26: I-34 I-35 II-3 II-4 II-1 xxv
Page 27 and 28: III-2 III-1 III-3 III-4 III-5 III-6
Page 29 and 30: V-7 V-8 V-9 V-10 V-11 V-12 V-13 V-1
Page 31 and 32: Chapter 1 - General Introduction 1.
Page 33 and 34: linear relationship shown in Figure
Page 35 and 36: A plot of χT vs. T is an important
Page 37 and 38: examination of phenyl methylene. In
Page 39 and 40: different atomic nuclei. Qualitativ
Page 41 and 42: 3) 14 and a variety of thiazyl base
Page 43 and 44: with one another with an energy bar
Page 45 and 46: magnetic properties and undergoes a
Page 47 and 48: heteroatoms which could facilitate
Page 49 and 50: Figure 1-5. Qualitative molecular o
Page 51 and 52: temperature. 64 This was a very imp
Page 53: dimerization and therefore a quench
Page 57 and 58: eaches the lower end of the investi
Page 59 and 60: DTDAs has been to exploit the rearr
Page 61 and 62: 1.3.4 1,2,3-Dithiazolyl Radicals (I
Page 63 and 64: aromatic ring not only protects the
Page 65 and 66: is quite similar to the spin-polari
Page 67 and 68: compound there are many competing m
Page 69 and 70: a b c d e Figure 1-16. a) Nonorthog
Page 71 and 72: would result in non-orthogonal over
Page 73 and 74: platinum center as well as the phos
Page 75 and 76: substantial amount of unpaired elec
Page 77 and 78: I-28 I-29 I-30 The metals manganese
Page 79 and 80: gave a combination of 2 mononuclear
Page 81 and 82: changes related to geometric, chemi
Page 83 and 84: Finally, the last chapter reviews t
Page 85 and 86: (23) Rajca, A. Chem. Rev. 1994, 94,
Page 87 and 88: (53) Azuma, N.; Tsutsui, K.; Miura,
Page 89 and 90: (79) Decken, A.; Cameron, T. S.; Pa
Page 91 and 92: (102) Herz, R.; Leopold Cassella &
Page 93 and 94: (128) Aliaga-Alcalde, N., 2003. (12
Page 95 and 96: Chapter 2 - Structural and Magnetic
Page 97 and 98: 2.2.2 pymDSDA Coordination Complexe
Page 99 and 100: 2.2.3 DTDA Coordination Complexes o
Page 101 and 102: indicators tend to be very weak str
Page 103 and 104: In Figure 2-1a, the nickel complex
Page 105 and 106:
2.2.3 Cyclic Voltametry The cyclic
Page 107 and 108:
propensity for intermolecular Se-N
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dimerization motif. One possible ex
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the bridging ligand such that the D
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contacts into four different intera
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e acting as a closed-shell, S = 0,
Page 117 and 118:
2.3.4 [Zn(hfac) 2 ] 2·pymDTDA (II-
Page 119 and 120:
ancillary ligands and the nearly oc
Page 121 and 122:
single molecular unit. Upon closer
Page 123 and 124:
across the entire temperature regim
Page 125 and 126:
2.5 Conclusions and Future Work It
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therefore chain formation. However
Page 129 and 130:
The work presented in this chapter
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736(s), 723(s), 646(s), 632(s), 469
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(0.2023 g, 1.104 mmol) in 30 mL of
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(6) Chattoraj, S. C.; Cupka Jr, A.
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Chapter 3 - 5-oxo-5H-naphtho[1,2-d]
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triethylammonium chloride which was
Page 141 and 142:
3.3.2 Mass Spectrometry A sample of
Page 143 and 144:
3.3.4 X-ray Crystallography Crystal
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a 2-fold screw axis across half of
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number of electrons that this compo
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often generated in situ although wa
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similar to compounds II-1 and II-2,
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3.6 Experimental General All reacti
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Chapter 4 - The Polymorphism of Tri
Page 157 and 158:
4.3 Discussion Prior to the discove
Page 159 and 160:
(derived from angles ranging from 4
Page 161 and 162:
a b c Figure 4-2. Packing diagrams
Page 163 and 164:
polymorphs observed and are therefo
Page 165 and 166:
Chapter 5 5.1 Overview There are se
Page 167 and 168:
success and so a Herz ring closure
Page 169 and 170:
did not immediately precipitate, bu
Page 171 and 172:
Figure 5-2 shows the IR spectra for
Page 173 and 174:
comparison of the infrared data obt
Page 175 and 176:
discussed in section 5.2.2. As the
Page 177 and 178:
ing was formed. One of the nitrogen
Page 179 and 180:
equired to obtain a decent agreemen
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Considerations have been put toward
Page 183 and 184:
chelation pocket is similar to that
Page 185 and 186:
the mixture was filtered to remove
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good spectroscopic handle for this
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spectrum from about 1900 to 400 cm
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doublets of triplets associated wit
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adical, followed by the closed-shel
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completely dry after being under va
Page 197 and 198:
changed substantially after the tra
Page 199 and 200:
The reaction to produce V-15 was qu
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the proton two carbons away next to
Page 203 and 204:
which is parallel to the mean plane
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of the 1,2,3-DTA rings could act as
Page 207 and 208:
mixture was refluxed for 20 h yield
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the heat source was removed and the
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1085(w), 1059(w), 1008(w), 917(w),
Page 213 and 214:
___________________________________
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Crystallography P 2 1 /c a = 9.1678
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Compound Name: 4-(2′-pyrimidyl)-1
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Compound Name: [μ-4-(2′-pyrimidy
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Magnetometry 192
Page 223 and 224:
Crystallography P-1 a = 8.9576, b =
Page 225 and 226:
Compound Name: [μ-4-(2′-pyrimidy
Page 227 and 228:
Magnetometry: 198
Page 229 and 230:
Crystallography: P2 1 /n a = 19.884
Page 231 and 232:
Compound Name: 5-oxo-5H-naphtho[1,2
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204
Page 235 and 236:
206
Page 237 and 238:
MS (EI + ): 208
Page 239 and 240:
Compound Name: 5-chloro-1H-[1,2,5]t
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Compound Name: 3-nitro-1,2-naphthaq
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Compound Name: 3,4-dioxo-3,4-dihydr
Page 245 and 246:
Compound Name: 4,5-dioxo-4,5-dihydr
Page 247 and 248:
Compound Name: 6,6′-dinitro-1,1
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220
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222
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1,2,3-Dithiazolyl and 1,2,35-Dithiadiazolyl Radicals as Spin-Bearing ...

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