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

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interactions as the closest contact to the acetyl carbonyl is with a hydrogen atom on an sp 3 hybridized carbon atom from the acetyl methyl group of an adjacent molecule. This contact is outside of the van der Waals radius of the two atoms and would not be expected to have a significant influence on the packing. It is therefore plausible that use of an isopropyl group substituted on this oxygen (III-8) could potentially pack in a similar way as the only difference would be that the carbonyl oxygen which has no electrostatic preference for its position would instead be another methyl group. If that were the case, and it was true that the radical anion was chemically reversible and could be accessed, then the sulfur-oxygen contacts would likely be more favourable as the oxygen atom taking part in these interactions would have a formal negative charge enhancing the electrostatic attraction to the electropositive sulfur atom to the 1,2,3-DTA ring of the a neighbouring complex. Since the SOMO would have density on the sulfur atoms and the oxygen atom, there is a potential for magnetic exchange coupling to take place between molecular radical units thus providing a very interesting compound even prior to coordination. While the primary compound of focus for this chapter did not possess the chemical reversibility upon reduction that we were looking for which would indicate a stable radical anion, it has shown that the hydroxyl group of III-1 is prone to substitution of the oxygen atom. Careful studies must be performed to determine the ideal conditions required to effect these substitutions as the formation of III-1 is quite favourable and very sensitive to the presence of impurities from the solvent or starting materials. If however these conditions are discovered, it could open up avenues for very interesting complexes such as those mentioned here as well as other potentially interesting possibilities. 123
3.6 Experimental General All reactions and manipulations were performed under an argon atmosphere using standard Schlenk techniques. Solvents were dried and distilled under argon prior to use: tetrahydrofuran (THF) was dried over sodium/benzophenone ketyl, acetyl chloride was distilled over PCl 5 and triethyl amine over P 2 O 5 . The preparation of III-1 was carried out according to the thesis of a previous student and sublimed prior to use. 1 All other reagents were purchased from Aldrich and used as received. IR spectra were recorded as pressed KBr pellets on a Nicolet 510-FTIR spectrometer at ambient temperature. Electrochemical measurements were obtained at ambient temperature using an Autolab PGSTAT 30 instrument and a three-electrode (platinum) glass cell, sealed under an argon atmosphere. 5-oxo-5H-naphtho[1,2-d][1,2,3]dithiazol-4-yl acetate (III-3). III-1 (0.2333 g, 0.9915 mmol) was dissolved in dry THF (30 mL) and an excess of triethylamine was added (0.1452g, 1.435 mmol) to give a dark violet solution. After 15 minutes, a slight excess of acetylchloride (0.1105 g, 1.408 mmol) was added to give a light orange reaction mixture which was stirred at room temperature for 2 hours. A pale, off-white solid was filtered and characterized to reveal that it was triethyl ammonium chloride. The dark orange filtrate was evaporated under vacuum to give the title compound as a red powder (0.1749 g, 0.6307 mmol) 64% yield based on III-1. Crystals suitable for X-ray crystallography were grown by dynamic vacuum sublimation at 120 °C. ν max (KBr)/cm −1 : 3271(w), 1759(s), 1616(m), 1610(m), 1590(s), 1582(s), 1541(s), 1497(s), 1455(m), 124
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1,2,3-Dithiazolyl and 1,2,35-Dithia
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an individual binuclear coordinatio
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weren’t sure about something our
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2.1 General........................
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5.3 Reverse oDTANQ.................
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LIST OF FIGURES AND SCHEMES Figure
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Figure 2-12. Magnetic susceptibilit
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GLOSSARY OF ABBREVIATIONS ° Degree
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K k k B LMCT ls LUMO Kelvin Exchang
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LIST OF STRUCTURES I-1 I-2 I-3 I-4
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I-16a I-16b I-16c I-16d I-16e I-16f
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I-22 I-23 I-24 I-25 exo I-26 endo x
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I-34 I-35 II-3 II-4 II-1 xxv
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III-2 III-1 III-3 III-4 III-5 III-6
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V-7 V-8 V-9 V-10 V-11 V-12 V-13 V-1
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Chapter 1 - General Introduction 1.
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linear relationship shown in Figure
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A plot of χT vs. T is an important
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examination of phenyl methylene. In
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different atomic nuclei. Qualitativ
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3) 14 and a variety of thiazyl base
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with one another with an energy bar
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magnetic properties and undergoes a
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heteroatoms which could facilitate
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Figure 1-5. Qualitative molecular o
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temperature. 64 This was a very imp
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dimerization and therefore a quench
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e enough to overcome the energetica
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eaches the lower end of the investi
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DTDAs has been to exploit the rearr
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1.3.4 1,2,3-Dithiazolyl Radicals (I
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aromatic ring not only protects the
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is quite similar to the spin-polari
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compound there are many competing m
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a b c d e Figure 1-16. a) Nonorthog
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would result in non-orthogonal over
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platinum center as well as the phos
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substantial amount of unpaired elec
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I-28 I-29 I-30 The metals manganese
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gave a combination of 2 mononuclear
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changes related to geometric, chemi
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Finally, the last chapter reviews t
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(23) Rajca, A. Chem. Rev. 1994, 94,
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(53) Azuma, N.; Tsutsui, K.; Miura,
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(79) Decken, A.; Cameron, T. S.; Pa
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(102) Herz, R.; Leopold Cassella &
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(128) Aliaga-Alcalde, N., 2003. (12
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Chapter 2 - Structural and Magnetic
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2.2.2 pymDSDA Coordination Complexe
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2.2.3 DTDA Coordination Complexes o
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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
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: similar to compounds II-1 and II-2,
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
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Page 185 and 186: the mixture was filtered to remove
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which is parallel to the mean plane
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of the 1,2,3-DTA rings could act as
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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),
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___________________________________
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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
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Crystallography P-1 a = 8.9576, b =
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Compound Name: [μ-4-(2′-pyrimidy
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Magnetometry: 198
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Crystallography: P2 1 /n a = 19.884
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Compound Name: 5-oxo-5H-naphtho[1,2
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204
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206
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MS (EI + ): 208
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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
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Compound Name: 4,5-dioxo-4,5-dihydr
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Compound Name: 6,6′-dinitro-1,1
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220
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1,2,3-Dithiazolyl and 1,2,35-Dithiadiazolyl Radicals as Spin-Bearing ...

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