220355-06-6Relevant academic research and scientific papers
Transition-metal complexes with sulfur ligands. 132.1 electron-rich Fe and Ru complexes with [MN2S3] cores containing the new pentadentate ligand 'N2H2S3'2- (= 2,2′-Bis(2-mercaptophenylamino)diethyl sulfide(2-))
Sellmann, Dieter,Utz, Jürgen,Heinemann, Frank W.
, p. 459 - 466 (1999)
The new pentadentate amine thioether thiolate ligand 'N2H2S3'-H2 (= 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 'N2H2S3'2- with Fe2+ yielded the dinuclear high-spin complex [Fe('N2H2S3')]2 (5). Complex 5 added CO to give the low-spin complex [Fe(CO)('N2H2S3')] (6) whose low frequency v(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 'N2H2S3'2- yielded [Ru(CO)(PCy3)('N2H2S3')] (7), [Ru(PPr3)2('N2H2S3')] (8), [Ru(PR3)('N2H2S3')] (R = Pr (9), Ph (10)), and [Ru-(NO)('N2HS3')] (13). In complexes 7 and 8, 'N2H2S3'2- acts as a tetradentate ligand. When heated in solution, complex 8 dissociates one PPr3 ligand to give 9. Complex 13 contains the trisanionic 'N2HS3'3- resulting from deprotonation of one amine NH function. All [Ru(L)('N2H2S3')] complexes proved inert toward dissociation of the Ru-L bonds. The NH functions of [M(L)('N2H2S3')] complexes are acidic and show H+/D+ exchange reactions with D2O. Methylation of the thiolate donors in 10 yielded the thioether derivative [Ru(PPh3)('N2H2S3'-Me 2)]I2 (11) whose PPh3 ligand is as inert to substitution as that of 10. Complex 11 can reversibly be deprotonated to give [Ru(PPh3)('N2HS3'-Me2)]I (12). NMR spectroscopic investigations showed that the deprotonation/protonation reactions of 11 and 12 are stereoselective. In contrast, protonation of 13 with HBF4 gives two diastereomers of the corresponding [Ru(NO)('N2H2S3')]BF4 salt (14). X-ray structure analyses of 5, 6, 9, and 11 and NMR spectra showed that the 'N2H2S3'2- ligand and its derivatives bind to the metal centers in the same fashion which combines fac and mer coordination of the donor atoms. The [MN2S3] cores of all complexes have an analogous C1 symmetrical structure in which both the two N and the two terminal S donors assume cis positions.
