Syntheses, Structures and Reactivity of Electron‐Rich Fe and Ru Complexes with the New Pentadentate Ligand Et₂NpyS₄−H₂ {4‐(Diethylamino)2,6‐bis[(2‐mercaptophenyl)thiomethyl]pyridine}

Abstract

The new pentadentate thioether thiolate ligand Et2NpyS42− {= 4‐(diethylamino)‐2,6‐bis[(2‐mercaptophenyl)thiomethyl]pyridine(2−)} has been synthesised from dimethyl 4‐bromopyridine‐2,6‐dicarboxylate by treatment with Et2NH followed by reduction and tosylation. The tosylated product was subsequently used for the template alkylation of [Ni(S2C6H4)2]2− to give [{Ni(Et2NpyS4)}2] (4). Acidic hydrolysis of 4 resulted in the formation of the ligand Et2NpyS4−H2·HCl (5). The dianion Et2NpyS42− reacted with FeCl2·H2O to afford the dinuclear high‐spin species [{Fe(Et2NpyS4)}2] (6) [μeff (297 K) = 5.15 μB]. Aerial oxidation of dinuclear 6 afforded the sulfinato complex [{Fe(Et2NpyS4−O2)}2] (7). Complex 6 proved to be a good precursor for the syntheses of [Fe(L)(Et2NpyS4)] [L = CO (8), CNCy (9), NO (11) and N2H4 (12)] and [Fe(NO)(Et2NpyS4)]BF4 (10). Protonation or alkylation of the thiolate donor atoms resulted in a series of complexes [Fe(CO)(Et2NpyS4−R)]BF4 [R = H (8a), Et (8b)] and [Fe(CO)(Et2NpyS4−Et2)](BF4)2 (8c) but no labilisation of the Fe−CO bond was observed. Only in complex 8 could the CO coligand be exchanged by NO+ to give [Fe(NO)(Et2NpyS4)]BF4 (10). Reduction of 10 using N2H4, NH3 or N3− afforded the 19 valence electron species [Fe(NO)(Et2NpyS4)] (11). [Ru(NO)(Et2NpyS4)]Br (13) was synthesised by template alkylation of Bu4N[Ru(NO)(S2C6H4)2] using Et2Npy(CH2Br)2 (3). Under reducing conditions, 13 releases the NO coligand to give [{Ru(Et2NpyS4)}2] (14), while in the presence of N2H4, [Ru(N2H4)(Et2NpyS4)] (15) was formed. The complexes were well characterised including the solid‐state structures in most cases. X‐ray structural analyses of 7, 8, 9, 10, 12 and 15 revealed that all complexes exhibit trans‐thiolate donors irrespective of the σ−π‐ or σ‐ligand character of L. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

Oxidation of Ru-bound thiolate thioether and its NS4-ligand containing thiolate and thioether sulfur donors: synthesis, characterization, and X-ray structures

“…Oxidation of sulfur and consequent exchange of the co-ligand N 2 H 4 by H 2 O is an interesting phenomenon in relation to hydrogen bonding. The exchange of N 2 H 4 by H 2 O may happen due to the fact that the N 2 H 4 co-ligand is stable only in the presence of hydrogen bonding as reported earlier [7]. Oxidation of the sulfur donors damages the hydrogen bonding and as a result the N 2 H 4 decoordinates to leave a free coordination site.…”

“…Reactions with O 2 are distinct from reactions with H 2 O 2 in that the former can lead to products incorporating both atoms of O 2 (a four-electron, dioxygenase-like oxidation), whereas peroxide sequentially oxidizes sulfur by two electrons with the transfer of one oxygen. In a previous paper, we found that the iron thiolate can be converted to a S-bound sulfinato complex by the incorporation of dioxygen [7]. In this article we report an oxidation of a Ru(II) alkylthiolate hydrazine complex 3 upon reaction with H 2 O 2 that also leads to ligand oxidation.…”

“…The syntheses of 1 and 3 have been reported previously [7]. Reactions accomplished in this work are depicted in scheme 1.…”

“…Et 2 NpyS 4 -H 2 and [Ru(N 2 H 4 )(Et 2 NpyS 4 )] were synthesized as described [7]. Hydrogen peroxide (30%) was purchased from Fischer Scientific Co. All manipulations were carried out in Schlenk lines and dry solvents were used.…”

Carbon-sulfur bond formation via alkene addition to an oxidized ruthenium-thiolate.

“…21 The Ru-S(1) bond length is 2.3856(9) Å and is close to previously reported Ru-S thiolate bonds. [43][44][45][46] The Ru-S thioether bond lengths in 2a for Ru-S2 and Ru-S3 are …”