| dc.description.abstracteng | In this work, novel metal complexes of the sulfur-nitrogen ligand, [S(NtBu)4]2-, were synthesized by exchange of lithium atoms or by other metal salts. Moreover, novel lithium complexes of asymmetric hydrogen tetraimido sulfate, [S(NR)4]2-, were obtained. Furthermore, a novel synthesis of the di(tertbutyl)seleniumdiimide, Se(NtBu)2, was carried out. The synthesized complexes were characterized by e.g. X-ray diffraction, NMR spectroscopy and elementary analysis.
A copper acetylacetonate coordinated compound could be synthesized by the reaction of a soft transition metal, copper acetylacetonate, and the lithiated starting material. The first heterobimetallic complex of [S(NtBu)4]2- was obtained with the hard transition metal zinc chloride and [LiN(SiMe3)2] to give [{Li(thf)2}{Zn(N(SiMe3)2)}{(NtBu)4S}]. [{(thf)3Li}2(FeCl)2(NtBu)4S] resembles the catalytically most promising Fe(II)-Cl-alkali metal bridge known from N2 activation. In all these complexes, the S–N bonds vary only marginally between the different metal cations. The S–N bond distances sum up to 6.37(3) Å, from which can be concluded that the electropositive sulfur responds to the metal-polarized negative charge at the outside of the [S(NR)4]2- tetrahedron. In all complexes, polarized sulfur-nitrogen bonds with a covalent character and an additively ionic part are present, which is responsible for the shorter bonding.
Moreover, by defined hydrolyses with water, several interesting metal compounds could be obtained. Also, different metal cations could be coordinated in this way, which reflects the high flexibility of this ligand. For these three complexes it could also be assumed that polarized sulfur-nitrogen bonds with a covalent character and an additively ionic part are present.
Furthermore, two novel tetrahedrally coordinated sulfur compounds with differently coordinated Lewis bases, [(py)4Li2(NtBu)4S] and [(dme)2Li2(NtBu)4S], could be obtained. Additionally, novel asymmetric complexes of a tetrahedrally coordinated sulfur atom with three equal and one variable imido group could be synthsized and characterized. It could be shown that the variation of the imido group influences the S(N4R3R’)2- ligand so that one nitrogen atom could be protonated and only the mono lithiated species of this sulfur-nitrogen ligand was synthesized.
Finally, the hydrolyzed di(tertbutyl)seleninyldiimide and the di(tertbutyl)seleniumdiimide could be synthesized and characterized. The literature known synthesis of Se(NtBu)2 always led to a mixture of the desired compound and the hydrolyzed form, OSe(NHtBu)2. The non-hydrolyzed species could only be obtained by an optimized reaction pathway. The syn, anti conformation of the moieties in Se(NtBu)2 could be confirmed in solid state.
The fourfoldly coordinated sulfate, [S(NR)4]2-, is a variable ligand system which can coordinate soft to hard transition metals. The variation of the moieties and the center atom open a broad field of novel metal complexes. | de |