Many kinds of radicals are stable enough to isolate, handle, and store without any special precautions. The diversity in molecular architectures of these stable radicals is sufficiently large that the common factors governing radical stability/persistence, geometric and electronic structure, association/dimerization preferences, and reactivity have generally not been well articulated or appreciated. This review provides a survey of the major classes of stable or persistent organic/organomain group radicals with a view to presenting a unified description of the interdependencies between radical molecular structure and properties.

What's new in stable radical chemistry?

Phosphorane iminato complexes of main group elements

The Chemistry of Dithiadiazolylium and Dithiadiazolyl Rings

Electrochemistry of redox-active Group 15/16 heterocyles

The dithiadiazolyl radicals are a group of heterocyclic sulfur–nitrogen-containing neutral radicals. These molecules have received a great deal of attention due to their potential as building blocks for the development of molecular magnets and molecular conductors. Both magnetic and conducting properties are directly related to solid-state structure, and as a result dithiadiazolyl radicals have been the target of numerous systematic studies into the effects of molecular structure on crystal structure. This article will trace the advances in understanding of the factors affecting solid-state structure in this interesting class of molecules.

Crystal engineering with dithiadiazolyl radicals

The search for neutral, low-dimensional conducting materials has kindled interest in the preparation and study of heterocyclic thiazyl radicals, recent attention has been focused on 1,2,3,5-dithiadiazolyls. These planar seven-{pi}-electron radicals are known to associate in the solid state in one of two modes, (R = Ph) and 3(R = CF{sub 3}, NMe{sub 2}, Me{sup 6}). To date, however, there is no evidence of the desired packing mode, i.e., vertical stacks of uniformly spaced radicals. In order to test the effect on interdimer interactions of the replacement of sulfur by selenium, we have prepared and structurally characterized the hitherto unknown, 1,2,3,5-diselenadiazolyl (R = Ph).

1,2,3,5-Diselenadiazolyls as building blocks for molecular metals. Preparation and structures of [PhCN2Se2]+PF6- and [PhCN2Se2]2

Crystal, molecular, and electronic structure of tetrasulfur dinitride, S4N2

The reaction of norbornadiene with (triphenylphosphoranediyl)aminocyclotrithiatriazene produces the cycloadduct Ph3PN—S3N3•C7H8. The crystal and molecular structure of this compound has been determ...

S. W. Liblong

Papers

1,2,3,5-Diselenadiazolyls as building blocks for molecular metals. Preparation and structures of [PhCN2Se2]+PF6- and [PhCN2Se2]2

Crystal, molecular, and electronic structure of tetrasulfur dinitride, S4N2

The cycloaddition of norbornadiene to (triphenylphosphoranediyl)aminocyclotrithiatriazene; the crystal and molecular structure of Ph3PN—S3N3•C7H8

Specific syntheses of the unsaturated phosphorus−nitrogen−sulfur rings R2PN3S2, 1,5-(R2P)2N4S2 and R2PN5S3 (R=Ph, Me)

Lewis base properties of 1,5-diphosphadithiatetrazocines: crystal and molecular structures of 1,5-Ph4P2N4S2Me+CF3SO3-