Roland Fleischer

A new route to sulfur polyimido anions S(NR)nm−: reactivity and coordination behavior

In a reaction sequence of amide addition followed by halogen oxidation the triazasulfite S(NR)32− and the tetrazasulfate S(NR)42− are readily accessible from sulfur diimide S(NR)2 via sulfur triimide S(NR)3. Addition of lithium organics to sulfur triimide provides a general route to triazasulfonates RS(NR)3−. All these anions resemble potential tripodal coordination behavior because of their nitrogen donor centers. Furthermore, the sulfur polyimido ligands are capable of responding to the various requirements of different metals (even in mixed metal species) by charge (de)localization. This review deals with the synthetic routes to the sulfur nitrogen anions and with their coordination behavior. The reactivity mainly towards main group metal synthons is discussed.

Synthesis and structure of alkaline earth metal diazasulphinates and triazasulphites

Abstract The syntheses and solid state structures of (THF2M{(NSiMe3)2SPh}2] (M=Ca, 1; M=Sr, 2; M=Ba 3) and (THFnM{(NSiMe3)2SN(SiMe3)2}2] (M=Mg, n=0, 4; M=Sr, n=1, 5) are presented. Although the (Me3Si)2NS(NSiMe3)2− anion resembles to a large extent the structural features of the PhS(NSiMe3)2− anion, careful examination of structural parameters reveals marginal differences in their coordination to alkaline earth metal dications. Above all, bonding to the metals is predominantly ionic, but the nature of the small covalent contribution differs in both anionic systems. Strictly planar SN2M four-membered rings in 1, 2 and 3 indicate exclusively σ-bonding of the PhS(Me3SiN)2− anion towards the alkaline earth metal. The SN2 moiety of the (Me3Si)2NS(NSiMe3)2− anion seems to be more π electron rich. The metal is not located in the plane of the N–S–N chelating ligand, but is displaced from the plane towards the sulphur atom to interact with the π electron density. This effect is caused neither by the steric demand of the ligand nor by packing effects but is induced by the different electronic nature of the ligand. Structural comparisons to related systems substantiate these findings. The size and polarizability of barium, in particular, enables this metal to interact with the non-directed π electron density of the SN2 fragment.

Synthesis and structures of paramagnetic organo titanium fluoride clusters

Abstract The organo titanium(IV)trifluoride [C 5 H 4 (SiMe 3 )]TiF 3 , 2 , has been reduced with zinc and manganese, respectively. As an intermediate product from these reactions the tetra-nuclear Ti III cluster {[C 5 H 4 (SiMe 3 )] 2 TiF 2 } 3 Ti, 3 , has been obtained. By oxidative fluorination using AgF complex 3 was converted to the titanium(IV) complex [C 5 H 4 (SiMe 3 )] 2 TiF 2 . Reduction of (C 5 H 5 ) 2 TiF 2 with gallium led to the formation of [(C 5 H 5 ) 2 TiF 2 ] 3 Ga, 7 .

Formation and co-coordination of lithium azide via lithium triazasulfite

The triazasulfite [Li4{(NBut)3S}2] (the analogue of Li2SO3) provides the opportunity to complex in situ formed lithium azide and converts this inorganic solid into soluble monomeric residues.

A supramolecular motif in the solid-state structure of a difunctional thallium(i) amide defined by weak Tl···Tl attractions

The crystal structure of the difunctional thallium(I) amide CH 2 [CH 2 N(Tl)SiMe 3 ] 2 1 reveals a pattern of aggregation based on weak attractive metal–metal interactions, a situation which appears to be influenced by the degree of exposure of the thallium centres; this is evidenced by the solid-state structure of the more shielded analogue CH 2 [CH 2 N(Tl)SiBu t Me 2 ] 2 2 which features no significant Tl···Tl contacts.