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

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I-18a I-18b Figure 1-10. Orbital overlap model of the orthogonal dimerization mode seen for I-18b. The synthetic methodology for the generation of I-18 based systems is very similar to that outlined in scheme 1-1. However the selenium dichloride which is used is not stable. This compound exists only in equilibrium with selenium tetrachloride and chloride ions in solution 100 and was once postulated to not even exist by early researchers. 101 For this reason the selenium dichloride was generated in situ first by the combination of SeCl 4 and SbPh 3 in acetonitrile, 91 but was then later adapted to a combination of elemental selenium and SeCl 4 which removes the impurities associated with the SbPh 3 Cl 2 byproduct. 94 This provides the diselenadiazolium chloride salt precursor to the radical which can then be reduced, usually with triphenyl antimony as for the I-16 analogues, to afford the radical species. 30
1.3.4 1,2,3-Dithiazolyl Radicals (I-17) The direct precursors to 1,2,3-DTA radicals (I-17) based radicals are the 1,2,3- dithiazolium salts which were first synthesized in 1922 from aniline hydrochloride and related derivatives to give the ring-closed species. 102 Four to five equivalents of sulfur monochloride are reacted with the primary amine of an aromatic or resonance stabilized species and interestingly the position para to the amine nitrogen is frequently chlorinated. 103 The reaction mechanism is not fully understood, however it has been Scheme 1-2. Herz Ring closure reaction. determined that at least four equivalents are actually required to push the reaction to completion. 104 The extraneous sulfur monochloride unfortunately results in the formation of a number of byproducts which have been isolated and characterized, such as non-chlorinated dithiazolium salts, sulfur diimines, both cyclic and acyclic compounds, azo-benzene species and benzothiazoles. 103 Purification can be achieved by an anion metathesis and has been successfully employed for several anions such as (GaCl - 4 ), 105 triflate (OTf - ) and TeO 4 2- , 106 as well as AlCl 4 - , BF 4 - , ClO 4 - , AsF 6 - and SbCl 6 - . 103 Reduction of these salts to afford the radical species once employed the use of zinc dust, 107,108 but has more recently been accomplished with one electron reducing agents 31
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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........................
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: DTDAs has been to exploit the rearr
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
Page 109 and 110: 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,
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2.3.4 [Zn(hfac) 2 ] 2·pymDTDA (II-
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ancillary ligands and the nearly oc
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single molecular unit. Upon closer
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across the entire temperature regim
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2.5 Conclusions and Future Work It
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therefore chain formation. However
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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
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3.3.2 Mass Spectrometry A sample of
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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
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4.3 Discussion Prior to the discove
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(derived from angles ranging from 4
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a b c Figure 4-2. Packing diagrams
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polymorphs observed and are therefo
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Chapter 5 5.1 Overview There are se
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success and so a Herz ring closure
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did not immediately precipitate, bu
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Figure 5-2 shows the IR spectra for
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comparison of the infrared data obt
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discussed in section 5.2.2. As the
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ing was formed. One of the nitrogen
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equired to obtain a decent agreemen
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Considerations have been put toward
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chelation pocket is similar to that
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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
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changed substantially after the tra
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The reaction to produce V-15 was qu
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the proton two carbons away next to
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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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222
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1,2,3-Dithiazolyl and 1,2,35-Dithiadiazolyl Radicals as Spin-Bearing ...

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