Transition metal complexes with sulfur ligands - 135 - Electron-rich Fe and Ru complexes with the new trisamine dithiolate ligand 'N3H3S2'-H-2 [2,2 '-bis(2-mercaptophenylamino)diethylamine]

In order to obtain iron and ruthenium complexes which are analogous to [M(L )('NHS4')] and [M(L)('N2H2S3')] complexes ['NHS4'(2-) = 2,2'-bis(2-mercapto phenylthio)diethylamine(2-), 'N2H2S3'(2-) = 2,2'-bis(2-mercaptophenylamino) diethylsulfide(2-)] but have electron-richer metal centers, the new pentade ntate amine thiolate ligand 'N3H3S2'-H-2 [= 2,2'-bis(2-mercaptophenylamino) diethylamine] (4) was synthesized. The dianion 'N3H3S2'(2-) reacted with Fe -II salts to give high-spin [Fe('N3H3S2')] (5) [mu(eff) (293 K) = 3.94 mu(B )], which yielded diamagnetic [Fe(CO)('N3H3S2')] (6) upon reaction with CO. Complex 6 exhibits a low-frequency nu(CO) band (1934 cm(-1) in THF) indica ting an electron-rich Fe center and a strong Fe-CO bond. In spite of this, 6 readily dissociated in solution to 5 and CO. The reaction of [RuCl2(PPh3) (3)] with 'N3H3S2'(2-) yielded [Ru(PPh3)('N3H3S2')] (7), which proved inert with respect to PPh3 substitution but could be methylated at the thiolate donors. The resulting [Ru(PPh3)('N3H3S2'-Me-2)]I-2 (8) proved as inert towa rds substitution as 7. Complex 8 could reversibly be deprotonated to give [ Ru(PPh3)('N3H2S2'-Me-2)]I (11), in the course of which the [RuPN3S2] cores rearrange from C-S to C-1 symmetry. Reversible protonation/deprotonation wa s also found with [Ru(NO)('N3H2S2')] (9) which formed from [RuCl3(NO)(PPh3) (2)] and 'N3H3S2'(2-) in the presence of one additional equivalent of LiOMe . Protonation of 9 with HBF, gave [Ru(NO)('N3H3S2')]BF4 (10). The NMR spect ra and the X-ray structure analysis of 8 proved that the [RuPN3S2] cores of 7 and 8 exhibit a C-S-symmetrical meso structure. In all other complexes, however, the [MLN3S2] cores exhibit a C-1-symmetrical structure. It results from the iac-mer coordination mode of the 'N3H3S2'(2-) ligand and favors t he planarization of amide donors when NH functions are reversibly deprotona ted.