Structural studies on some fluorinated dithiadiazolyl radicals

• Main Author: Haynes, D. A.
• Published: University of Cambridge 2002
• Subjects: 547.02
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.603890

A series of partially fluorinated 1,2,3,5-dithiadizolyl aryl derivatives was prepared, in order to examine the effects of the fluorinated substituents on the solid-state structure of these molecules. 3,5-(CF₃)₂(C₆H₃CNSSN and 3-CF₃C₆H₄CNSSN were synthesized, as well as nine isomers of CF₃FC₆H₃CNSSN. The crystal structures of seven of these derivatives are compared, and discussed in the light of their molecular electrostatic potential maps. 3-F-4-CF₃C₆H₃CNSSN was found to crystallize as an inclusion compound with nitrogen. The synthesis and characterisation of this inclusion compound is described, as well as the reactivity of 3-F-4-CF₃C₆H₃CNSSN to other small molecules (Ar, CO₂, O₂). Several fluorinated dithiadiazolyl derivatives were synthesized in order to investigate their physical properties. EPR studies on CF₃CNSSN were undertaken in order to further examine its known bistable nature. EPR studies on the novel dithiadiazolyl derivative, CF₃(CF₂)₆CNSSN are also described, and the possibility of this radical exhibiting a liquid crystalline phase is discussed. The synthesis and solid-state structure of novel monomeric dithiadiazolyl radical, (CF₃)₃C₆H₂CNSSN, is also described. During the course of these studies, the known dithiadiazolyl derivative, CICNSSN, was synthesized in three concomitant polymorphic forms. The solid-state structure of these compounds is described, and the competing interactions seen in the three forms are discussed in the light of the molecular electrostatic potential map and atomic partial charges of CICNSSN. A series of novel dithiatetrazocines, <i>p</i>-X₁C₆H₄C₂N₄S₂C₆H₄X₂ (X₁, X₂ = NO₂, Br) was synthesized and characterized in order to study the non-linear optical properties of the unsymmetric derivative. The solid-state structures of these three derivatives are described and rationalized using their molecular electrostatic potential maps.