Efficient uptake of dimethyl sulfoxide by the desoxomolybdenum(iv) dithiolate complex containing bulky hydrophobic groups

Abstract

A desoxomolybdenum(IV) complex containing bulky hydrophobic groups and NH···S hydrogen bonds, (Et4N)[Mo(IV)(OSi(t)BuPh2)(1,2-S2-3,6-{(4-(t)BuC6H4)3CCONH}2C6H2)2], was synthesized. This complex promotes the oxygen-atom-transfer (OAT) reaction of DMSO by efficient uptake of the substrate into the active center. The clean OAT reaction of Me3NO is also achieved.

Unexpected Reaction Promoted by NH+···O=Mo Hydrogen Bonds in Nonpolar Solvents

“…On the other hand, the solution of (LuH) 2 [ 1 ] in [D 8 ]toluene was green and exhibited broad 1 H NMR signals, suggesting the presence of paramagnetic molybdenum(V) species (Figure ). As shown in Figure , the absorption spectrum of this complex in toluene exhibited an absorption maximum at 756 nm, which is characteristic of [Mo V O( L ) 2 ] – . Interestingly, the intensity of the absorption indicated that [Mo IV O( L ) 2 ] 2– was converted quantitatively into [Mo V O( L ) 2 ] – .…”

“…The absorption spectra of the reaction mixture after 6 min are shown in Figure S9. The absorption spectral change for the reaction of (Et 3 NH) 2 [ 1 ] with two equivalents of Me 3 NO showed a rapid increase of both [ 2 ] 2– (at 398 and 560 nm) and [Mo V O( L ) 2 ] – (at 756 nm), followed by the immediate disappearance of [Mo V O( L ) 2 ] – . The resulting spectrum resembles that of the decomposed compound shown in Figure S8b, suggesting the dissociation of the ligand.…”

“…The use of 0.5 equiv. of Me 3 NO resulted in the predominant production of [Mo V O( L ) 2 ] – species (Figure , b) in 73 % yield, estimated from the maximum absorption of (Et 4 N)[Mo V O( L ) 2 ] that was generated by the one‐electron oxidation of (Et 4 N) 2 [ 1 ] using [Fe III (Cp) 2 ]BF 4 . Given that the recrystallisation of (Et 4 N)[Mo V O( L ) 2 ] gave (Et 4 N) 2 [Mo IV O( L ) 2 ] by autoreduction in solution, neither Et 4 N + nor Et 3 NH + salts of the Mo V species could be isolated.…”

Modeling of the hydrophobic microenvironment of water-soluble molybdoenzymes in an aqueous micellar solution

“…A weak and broad absorption band was observed at 770 nm during the catalytic reaction (Fig. 5), which suggests the presence of a monooxomolybdenum(V) species 23,29,30 generated by one-electron reduction as a side reaction.…”

Inspired by Nature—Functional Analogues of Molybdenum and Tungsten-Dependent Oxidoreductases

“…In their experiments, Ueyama et al found an accelerated addition of the oxygen of TMAO to the [Mo IV O(2N-bdt)2] 2− complex in contrast to the non-substituted related benzene-1,2-dithiolate-derived complexes introduced by Garner In the other type of half cycle reaction, a substrate donates its oxo function as an oxygen atom to the metal ion center accompanied by the oxidation of M IV to M VI . Respective OAT donor reagents/substrates are often derived from trimethylamine-N-oxide (TMAO) since this is actually also a natural substrate for TMAO reductase, or dimethylsulfoxide (DMSO), as in the DMSO reductase enzyme [30,33,51,52]. In 2006, Ueyama and others designed a novel aromatic dithiolene ligand 1,2-S 2 -3-R-CONHC 6 H 3 (2N-bdt; R=CH 3 , t Bu, CF 3 , CPh 3 , C(C 6 H 4 -4-t Bu) 3 ) (Figure 6b), bearing two amide moieties adjacent to the dithiolene in order to enable intramolecular hydrogen bonding in their complexes since H bonds play important roles for the enzymes' active sites and reactivities [53].…”