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

More documents

Recommendations

Info

attributed to the higher degree of spin-orbit coupling expected for the heavier selenium atoms in this species when compared to the sulfur analogues. 9 The spectrum for II-1 is shown in Figure 2-2 a. The binuclear zinc complex II-7 was also analyzed via EPR spectroscopy by creating a very dilute solution of the compound in methylene chloride such that the solution possessed no discernible colour. The spectrum is very similar to II-2 such that it is a simple 5-line pattern with intensity ratios of approximately1:2:3:2:1, indicating coupling to 2 equivalent nitrogen atoms. There are however several differences between the two spectra. The first is that the nitrogen coupling constant for II-7 (a N = 4.82 G) is smaller than that observed for II-2 (a N = 5.12 G), suggesting that spin density is delocalized away from the N atoms. Also, the g value for the metal complex (g = 2.038) is increased when compared to the value for the uncoordinated radical (g = 2.010). 3 Interestingly the increase in the g-shift is approximately the same for pymDSDA (g = 2.0382). a b c Figure 2-2. EPR spectra of a) II-1, g = 2.0382, b) II-7, a N = 4.82, g = 2.038 and c) II-2 a N = 5.12, g = 2.010. 74
2.2.3 Cyclic Voltametry The cyclic voltametry of II-1 was examined as a 4 mM solution in acetonitrile, using tetrabutylammonium hexafluorophosphate as the supporting electrolyte at a concentration of 0.18 M. As shown in Figure 2-3, the oxidation process is chemically reversible with an E ½ of 0.657 V vs. SCE, ΔE pp = 158 mV. The reductive process is not reversible, which is a common observation for these types of compounds and could be a result of the additional electron destabilizing the selenium-selenium bond causing it to suffer reductive cleavage. 10 The cathodic peak potential in the reductive process was measured to be -0.912 V vs. SCE. These data were standardized using the fc/fc + couple which, in acetonitrile with [ n Bu 4 N][PF 6 ], has an E½ value of 0.40 V vs. SCE. 11 Figure 2-3. Cyclic Voltamagram of II-1 showing individual peak potentials. The oxidative direction is to the right and the reductive direction is to the left. 75
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 and 54: dimerization and therefore a quench
Page 55 and 56: e enough to overcome the energetica
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: In Figure 2-1a, the nickel complex
Page 107 and 108: propensity for intermolecular Se-N
Page 109 and 110: dimerization motif. One possible ex
Page 111 and 112: the bridging ligand such that the D
Page 113 and 114: contacts into four different intera
Page 115 and 116: 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
Page 127 and 128: therefore chain formation. However
Page 129 and 130: The work presented in this chapter
Page 131 and 132: 736(s), 723(s), 646(s), 632(s), 469
Page 133 and 134: (0.2023 g, 1.104 mmol) in 30 mL of
Page 135 and 136: (6) Chattoraj, S. C.; Cupka Jr, A.
Page 137 and 138: Chapter 3 - 5-oxo-5H-naphtho[1,2-d]
Page 139 and 140: 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
Page 145 and 146: a 2-fold screw axis across half of
Page 147 and 148: number of electrons that this compo
Page 149 and 150: often generated in situ although wa
Page 151 and 152: similar to compounds II-1 and II-2,
Page 153 and 154: 3.6 Experimental General All reacti
Page 155 and 156:
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
Page 181 and 182:
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
Page 187 and 188:
good spectroscopic handle for this
Page 189 and 190:
spectrum from about 1900 to 400 cm
Page 191 and 192:
doublets of triplets associated wit
Page 193 and 194:
adical, followed by the closed-shel
Page 195 and 196:
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
Page 201 and 202:
the proton two carbons away next to
Page 203 and 204:
which is parallel to the mean plane
Page 205 and 206:
of the 1,2,3-DTA rings could act as
Page 207 and 208:
mixture was refluxed for 20 h yield
Page 209 and 210:
the heat source was removed and the
Page 211 and 212:
1085(w), 1059(w), 1008(w), 917(w),
Page 213 and 214:
___________________________________
Page 215 and 216:
Crystallography P 2 1 /c a = 9.1678
Page 217 and 218:
Compound Name: 4-(2′-pyrimidyl)-1
Page 219 and 220:
Compound Name: [μ-4-(2′-pyrimidy
Page 221 and 222:
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
Page 233 and 234:
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
Page 241 and 242:
Compound Name: 3-nitro-1,2-naphthaq
Page 243 and 244:
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
Page 249 and 250:
220
Page 251:
222
show all

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

Create successful ePaper yourself

Delete template?

Save as template?