ALKALI-METAL DERIVATIVES OF SULFINIMIDAMIDES - PREPARATION AND CRYSTAL-STRUCTURES

A series of compounds has been prepared in which the NH proton of the sulfiniminamines Me3SiN = S(R)-NHR' (R = Ph (mainly) or (t)Bu, R' = (t)Bu or SiMe3) is replaced by Li, Na, K, Rb, or Cs. The compounds form a series of reagents of increasing reactivity which could be used, for example, to introduce chelating ligands into transition metal complexes. The structures of the compounds have been determined by X-ray diffraction. When there is a phenyl substituent on the sulfur atom, the metal derivatives are isomorphic dimers, involving three fused four-membered rings in a step-shaped structure. The higher the atomic number of the metal, the stronger is the eta-coordination of the phenyl group to the metal. With a t-butyl group on the sulfur atom the structures of the lithium derivatives [(Me3SiN = S((t)Bu)-NR')Li]2 are different for R' = SiMe3 and (t)Bu. For the former the step-shaped structure is still present, but the latter forms an eight-membered ring. Although these (t)Bu derivatives are synthesized in diethyl ether, their lithium atoms are not coordinated by donor molecules, in contrast to those in the phenyl-substituted species.