Expanding the Utility of β-Diketiminate Ligands in Heavy Group VI Chemistry of Molybdenum and Tungsten

Abstract

We report the synthesis of 17 molybdenum and tungsten complexes supported by the ubiquitous BDI ligand framework (BDI = β-diketiminate). The focal entry point is the synthesis of four molybdenum and tungsten(V) BDI complexes of the general formula [MO(BDIR)Cl2] [M = Mo, R = Dipp (1); M = W, R = Dipp (2); M = Mo, R = Mes (3); M = W, R = Mes (4)] synthesized by the reaction between MoOCl3(THF)2 or WOCl3(THF)2 and LiBDIR. Reactivity studies show that the BDIDipp complexes are excellent precursors toward adduct formation, reacting smoothly with dimethylaminopyridine (DMAP) and triethylphosphine oxide (OPEt3). No reaction with small phosphines has been observed, strongly contrasting the chemistry of previously reported rhenium(V) complexes. Additionally, the complexes 1 and 2 are good precursors for salt metathesis reactions. While 1 can be chemically reduced to the first stable example of a Mo(IV) BDI complex 15, reduction of 2 resulted in degradation of the BDI ligand via a nitrene transfer reaction, leading to MAD (4-((2,6-diisopropylphenyl)imino)pent-2-enide) supported tungsten(V) and tungsten(VI) complexes 16 and 17. All reported complexes have been thoroughly studied by VT-NMR and (heteronuclear) NMR spectroscopy, as well as UV–vis and EPR spectroscopy, IR spectroscopy, and X-ray diffraction analysis.

A Versatile Comproportionation Route to Construct Mono‐Imido Trichlorido Complexes of Molybdenum(V) and Tungsten(V)

“…However, BDI coordinated W V complexes show substantially shorter WÀ O distances (1.693(4) Å). [37] Notably, a tert-butylamine analogue of 5, namely [W(N t Bu)Cl 3 (NH 2 t Bu)], [38] has been prepared by the reaction between WCl 6 and four equivalents of TMS-NH t Bu however, the product could only be obtained in single crystal quantities contrasting the bulk preparation reported herein. The WÀ N distance in this complex was found to be 1.726 Å and is thus similar to the one reported here.…”

Iron(III)-salophene catalyzes redox cycles that induce phospholipid peroxidation and deplete cancer cells of ferroptosis-protecting cofactors

“…The reaction mixture was transferred to a capillary tube and subjected to EPR measurements. EPR spectra were recorded in Quartz 3 mm OD J-Young style fused silica tubes (ATS Life Sciences Wilmad, Vineland, NJ) at −15 °C using a Magnettech MS-5000 X-band benchtop EPR spectrometer (Bruker, Billericia, MA) equipped with a variable temperature unit [ 65 ]. EPR spectrometer settings (modified according to Ref.…”