Electron-Rich Fe and Ru Complexes with the New Trisamine Dithiolate Ligand ′N3H3S2′-H2 [2,2′-Bis(2-mercaptophenylamino)diethylamine]

Abstract

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.

Transition Metal Complexes with Sulfur Ligands. 136.1 Enforced Trans Coordination of Thiolate Donors in Electron Rich Iron, Ruthenium, and Nickel [M(L)(pyN2H2S2)] and [M(L)(pyS4)] Complexes (L = CO, PPh3, DMSO) (pyN2H2S22- = 2,6-Bis(2-mercaptophenylamino)dimethylpyridine(2−); pyS42- = 2,6-Bis(2-mercaptophenylthio)dimethylpyridine(2−))

“…For the synthesis of pyN 2 H 2 S 2 -H 2 ( 3 ), we used the route which had proved successful in the preparation of the analogous N 2 H 2 S 3 -H 2 and N 3 H 3 S 2 -H 2 ligands. , Treatment of deprotonated 2(3 H )-benzothiazolone ( 1 ) with 2,6-bis[(tosyloxy)methyl]pyridine yielded 2 . Traces of byproducts resulting from O -alkylation of 1 were removed by extracting the crude product with EtOH.…”

“…Anticipating that a higher electron density at the Fe centers favors the binding of N 2 , we have tried to systematically exchange the potentially π-accepting S thioether functions 9 of the NHS 4 2- ligand for σ-donor NH amine functions. A series of pentadentate N x H x S y -H 2 ligands ( x + y = 5) was prepared (Scheme ). ,, The characteristic and, for our goals, important feature common to all these ligands are the terminal thiolate functions. The ν(CO) bands of the iron carbonyl complexes [Fe(CO)(N 2 H 2 S 3 )] and [Fe(CO)(N 3 H 3 S 2 )] (∼1930 cm -1 ) indeed indicate a higher electron density at the iron centers than in [Fe(CO)(NHS 4 )] (1960 cm -1 ).…”

(O,O′-Diethyl dithiophosphato-κ2S,S′)(hydridotripyrazol-1-ylborato-κ3N2,N2′,N2′′)(triphenylphosphine-κP)ruthenium(II)

“…In recent years there has been an increased interest in ruthenium sulfurcomplexes, in part because of the high catalytic activity of RuS 2 in various hydrotreating processes (Vit & Zdrazil, 1989). As a part of this development, many examples of ruthenium thiolate complexes have been reported, however, the ruthenium complexes with dithio ligands are relatively rare (Sellmann et al, 1999). On the other hand, ruthenium(II)hydridotripyrazolylborate complexes, Ru(Tp), are of interest for stoichiometricand catalytic transformations of organic molecules (Pavlik et al, 2005).…”

(Dithiobenzoato-κ2S,S′)[hydridotris(pyrazol-1-yl-κN2)borato](triphenylphosphine-κP)ruthenium(II)

“…Thus, many ruthenium thiolate complexes have been reported. However, ruthenium complexes with dithio ligands are relatively rare (Sellmann et al, 1999). In this context the structure of the title compound was determined.…”