Cuboidal Mo₃S₄ and Mo₃NiS₄ Complexes Bearing Dithiophosphates and Chiral Carboxylate Ligands: Synthesis, Crystal Structure and Fluxionality

Abstract

New triangular Mo and W cluster complexes incorporating (S)‐lactic acid (HLac), [Mo3S4(μ‐Lac)(dtp)3(py)] (1) and [W3S4(μ‐Lac)(dtp)3(py)] (2), were prepared [dtp = (EtO)2PS2]. Analogous synthetic procedures were adapted for the synthesis of cuboidal Mo3NiS4 to yield [Mo3(Nipy)S4(py)(μ‐OAc)(dtp)3(py)] (3). The crystal structures of 1 and 3 were determined. A detailed variable‐temperature 31P{1H} and 1H NMR study of compounds 1 and 3 indicated fluxional behaviour in non‐coordinating solvents (CDCl3, CD2Cl2 and CDCl2CDCl2). A number of dynamic processes were identified involving the Mo–py site that include configuration inversion [(P) to (M)], hindered Mo–N rotation and pyridine exchange. Experiments with deuterated pyridine revealed a faster substitutional lability of Mo–py compared with Ni–py.

Isolation of a New Cs‐Symmetrized Mo3(μ3‐S)(μ‐S)(μ‐S2)2 Structural Type Through Complementary Association with a Cubane‐Type Mo3NiS4 Cluster

“…Several protocols, including the judicious choice of counterions such as p ‐toluenesulfonate,18,19 for the derivatization by substitution of water molecules with a variety of ligands such as acetylacetonate,20 cyano,10 thiocyanate,21,22 or alkyl dithiophosphates,22 or for the formation of supramolecular compounds with cucurbit[ n ]urils,23 have allowed the crystallization and further characterization of this class of compounds. During our studies on ligand substitution reactions at the Mo sites in the aqua [Mo 3 S 4 (H 2 O) 9 ] 4+ cation we used a general protocol that comprises the derivatization of the [Mo 3 S 4 (H 2 O) 9 ] 4+ aqua ion by substitution of water molecules by diethyl dithiophosphate/acetate to facilitate the isolation and characterization of the resulting compounds 24. Unexpectedly, the reaction of an excess of potassium diethyl dithiophosphate with [Mo 3 S 4 (H 2 O) 9 ] 4+ in the presence of the cubane‐type [Mo 3 NiS 4 (H 2 O) 10 ] 4+ cation yielded a brown solid that was redissolved in acetonitrile/acetic acid mixtures and from which, after slow evaporation of the solvent at room temperature, a first brown crop of crystals was obtained.…”

“…The products [Mo 3 S 4 (dtp) 3 (μ‐OAc)(CH 3 CN)] and [Mo 3 (NiCH 3 CN)S 4 (dtp) 3 (μ‐OAc)(CH 3 CN)] (see Scheme ) result essentially from the substitution of water by dtp/carboxylate starting from [Mo 3 S 4 (H 2 O) 9 ] 4+ and [Mo 3 (NiCl)S 4 (H 2 O) 9 ] 3+ , respectively. The original synthetic protocol can be found elsewhere 24. [Mo 3 S 7 (dtp) 3 ] + (see Scheme ) was also present in the reaction mixture and its formation can be explained by the ability of the dtp ligand to act as a sulfurizing reagent to promote the transformation of Mo 3 S 4 to Mo 3 S 7 25.…”

Hemilability of phosphine-thioether ligands coordinated to trinuclear Mo3S4 cluster and its effect on hydrogenation catalysis

“…[63][64] Moreover, it has been reported that the dissociation/reassociation of one of the S atom of the S,S'-donor diethyldithiophosphate ligand most likely plays a key role in the dynamic processes in solutions of Mo 3 S 4 complexes of this ligand. [47,65] A similar mechanism involving partial de-coordination of the P,P'-donor diphosphine in [Mo 3 S 4 Cl 3 (dppe) 3 ] + was proposed to explain interconversion between the P-[Mo 3 S 4 Cl 3 (dppe) 3 ] + and M-[Mo 3 S 4 Cl 3 (dppe) 3 ] + enantiomers. Such de-coordination creates a vacant position at the metal, producing a Lewis acidic site that presumably catalyzes the [(tris(tetrachlorobenzenediolato)phosphate-(V)] (TRISPHAT) anion epimerization.…”

μ2-Acetato-κ2O:O′-(4,4′-bipyridyl-κN)tris(diethyl dithiophosphato-κ2S,S′)-μ3-sulfido-tri-μ2-sulfido-trimolybdenum(IV) diethyl ether monosolvate

“…For related compounds and their crystal structures, see: Hernandez-Molina et al (2011); Ogino et al (1998); Tang et al (2001); Yao et al (1995).…”