Mononuclear Organomolybdenum(VI) Dioxo Complexes: Synthesis, Reactivity, and Catalytic Applications

Methyltrioxorhenium and its applications in olefin oxidation, metathesis and aldehyde olefination

A cocrystal is only expected to form if it is thermodynamically more stable than the crystals of its components. To test whether this can be predicted with a current computational methodology, we compare the lattice energies of 12 cocrystals of 4-aminobenzoic acid, 8 of succinic acid and 6 of caffeine, with the sums of the lattice energies of their components. These three molecules were chosen for their potential use in pharmaceutical cocrystals and because they had sufficient determinations of cocrystals and corresponding partner crystal structures in the Cambridge Structural Database. The lattice energies were evaluated using anisotropic intermolecular atom−atom potentials, with the electrostatic model and the intramolecular energy penalty for changes in specified torsion angles derived from ab initio calculations on the isolated molecules. The majority of the cocrystals are calculated to be more stable than their components, but the energy difference is only large in a few of the cases where the partne...

Can the Formation of Pharmaceutical Cocrystals Be Computationally Predicted? I. Comparison of Lattice Energies

A Simple Entry to (η5-C5R5)chlorodioxomolybdenum(VI) Complexes (R = H, CH3, CH2Ph) and Their Use as Olefin Epoxidation Catalysts

The first members of the classes of the organorhenium(VII) oxides and organomolybdenum(VI) oxides were described during the 1960s and 1970s. However, despite the fact that methyltrioxorhenium(VII)
				(MTO) is probably the best examined organometallic oxide known, many of its derivatives as well as the Mo congeners were not tested for any application. Nevertheless, it is known that several organomolybdenum oxides, particularly those of formula η5-(C5R5)MoO2Cl and η5-(C5R5)MoO2R′ are powerful epoxidation catalysts if applied together with tert-butylhydroperoxide (TBHP). MTO catalyzes a broad variety of organic reactions, among them being olefin epoxidation – in this case with the “green” oxidant H2O2
				– the most thoroughly examined. The heterogenization of the molybdenum compounds as well as of MTO both on carrier materials and in ionic liquids has already been achieved and it is to be expected that a suitable modification of the organic ligands will lead to applications in chiral catalysis in the near future.

Organorhenium(VII) and organomolybdenum(VI) oxides: syntheses and application in olefin epoxidation

Complexes of the general formula [MoO 2 X 2 L 2 ] (X=Cl, Br, Me; L 2 =bipy, bpym) have been prepared and fully characterized, including X-ray crystallographic investigations of all six compounds. Additionally, the highly soluble complex [MoO 2 Cl 2 (4,4'-bis(hexyl)-2,2'-bipyridine)] has been synthesized. The reaction of the complexes with tert-butyl hydroperoxide (TBHP) is an equilibrium reaction, and leads to Mo V I η 1 -alkylperoxo complexes that selectively catalyze the epoxidation of olefins. Neither the Mo-X bonds nor the Mo-N bonds are cleaved during this reaction. These experimental results are supported by theoretical calculations, which show that the attack of TBHP at the Mo center through the X-O-N face is energetically favored and the TBHP hydrogen atom is transferred to a terminal oxygen of the Mo=O moiety. After the attack of the olefin on the Mo-bound peroxo oxygen atom, epoxide and tert-butyl alcohol are formed. The latter compound acts as a competitive inhibitor for the TBHP attack, and leads to a significant reduction in the catalytic activity with increasing reaction time.

Octahedral bipyridine and bipyrimidine dioxomolybdenum(VI) complexes: characterization, application in catalytic epoxidation, and density functional mechanistic study.

Michelle Groarke

Papers

Octahedral bipyridine and bipyrimidine dioxomolybdenum(VI) complexes: characterization, application in catalytic epoxidation, and density functional mechanistic study.

New insights into the reaction of t-butylhydroperoxide with dichloro- and dimethyl(dioxo)molybdenum(VI)