Transition-Metal Complexes with Sulfur Ligands. 132.(1) Electron-Rich Fe and Ru Complexes with [MN(2)S(3)] Cores Containing the New Pentadentate Ligand 'N(2)H(2)S(3)'(2)(-) (= 2,2'-Bis(2-mercaptophenylamino)diethyl Sulfide(2-)).
The new pentadentate amine thioether thiolate ligand 'N(2)H(2)S(3)'-H(2) (= 2,2'-bis(2-mercaptophenylamino)diethyl sulfide) (3) was synthesized in order to obtain iron and ruthenium complexes with high electron densities at the metal centers. The reaction of 'N(2)H(2)S(3)'(2)(-) with Fe(2+) yielded the dinuclear high-spin complex [Fe('N(2)H(2)S(3)')](2) (5). Complex 5 added CO to give the low-spin complex [Fe(CO)('N(2)H(2)S(3)')] (6) whose low frequency nu(CO) (1932 cm(-)(1)) indicates a high electron density at the iron center and a strong Fe-CO bond. However, 6 is labile and readily dissociates CO in solution. Treatment of suitable ruthenium precursor complexes with 'N(2)H(2)S(3)'(2)(-) yielded [Ru(CO)(PCy(3))('N(2)H(2)S(3)')] (7), [Ru(PPr(3))(2)('N(2)H(2)S(3)')] (8), [Ru(PR(3))('N(2)H(2)S(3)')] (R = Pr (9), Ph (10)), and [Ru(NO)('N(2)HS(3)')] (13). In complexes 7 and 8, 'N(2)H(2)S(3)'(2)(-) acts as a tetradentate ligand. When heated in solution, complex 8 dissociates one PPr(3) ligand to give 9. Complex 13 contains the trisanionic 'N(2)HS(3)'(3)(-) resulting from deprotonation of one amine NH function. All [Ru(L)('N(2)H(2)S(3)')] complexes proved inert toward dissociation of the Ru-L bonds. The NH functions of [M(L)('N(2)H(2)S(3)')] complexes are acidic and show H(+)/D(+) exchange reactions with D(2)O. Methylation of the thiolate donors in 10 yielded the thioether derivative [Ru(PPh(3))('N(2)H(2)S(3)'-Me(2))]I(2) (11) whose PPh(3) ligand is as inert to substitution as that of 10. Complex 11 can reversibly be deprotonated to give [Ru(PPh(3))('N(2)HS(3)'-Me(2))]I (12). NMR spectroscopic investigations showed that the deprotonation/protonation reactions of 11 and 12 are stereoselective. In contrast, protonation of 13 with HBF(4) gives two diastereomers of the corresponding [Ru(NO)('N(2)H(2)S(3)')]BF(4) salt (14). X-ray structure analyses of 5, 6, 9, and 11 and NMR spectra showed that the 'N(2)H(2)S(3)'(2)(-) ligand and its derivatives bind to the metal centers in the same fashion which combines fac and mer coordination of the donor atoms. The [MN(2)S(3)] cores of all complexes have an analogous C(1) symmetrical structure in which both the two N and the two terminal S donors assume cis positions.
Sellmann
Dieter
D
Institut für Anorganische Chemie, Universität Erlangen-Nürnberg, Egerlandstrasse 1, D-91058 Erlangen, Germany.
Utz
Jürgen
J
Heinemann
Frank W.
FW