ISSN:
1434-1948
Keywords:
N ligands
;
S ligands
;
Iron
;
Ruthenium
;
Pentadentate ligands
;
Chemistry
;
General Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
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-mercaptophenylthio)diethylamine(2-), ′N2H2S3′2- = 2,2′-bis(2-mercaptophenylamino)diethylsulfide(2-)] but have electron-richer metal centers, the new pentadentate amine thiolate ligand ′N3H3S2′-H2 [ = 2,2′-bis(2-mercaptophenylamino)diethylamine] (4) was synthesized. The dianion ′N3H3S2′2- reacted with FeII salts to give high-spin [Fe(′N3H3S2′)] (5) [μeff (293 K) = 3.94 μB], which yielded diamagnetic [Fe(CO)(′N3H3S2′)] (6) upon reaction with CO. Complex 6 exhibits a low-frequency ν(CO) band (1934 cm-1 in THF) indicating 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′-Me2)]I2 (8) proved as inert towards substitution as 7. Complex 8 could reversibly be deprotonated to give [Ru(PPh3)(′N3H2S2′-Me2)]I (11), in the course of which the [RuPN3S2] cores rearrange from CS to C1 symmetry. Reversible protonation/deprotonation was 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 HBF4 gave [Ru(NO)(′N3H3S2′)]BF4 (10). The NMR spectra and the X-ray structure analysis of 8 proved that the [RuPN3S2] cores of 7 and 8 exhibit a CS-symmetrical meso structure. In all other complexes, however, the [MLN3S2] cores exhibit a C1-symmetrical structure. It results from the fac-mer coordination mode of the ′N3H3S2′2- ligand and favors the planarization of amide donors when NH functions are reversibly deprotonated.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
