Dimanganese and diiron complexes of a binucleating cyclam ligand: four-electron, reversible oxidation chemistry at high potentials

Dinuclear manganese(iii) complexes with bioinspired coordination and variable linkers showing weak exchange effects: a synthetic, structural, spectroscopic and computation study

High-resolution HFEPR indicates weak exchange interactions between Mn^III ions in agreement with DFT calculations.

Synthesis, characterization and catalytic epoxidation properties of a new tellurotungstate(iv)-supported rhenium carbonyl derivative

We synthesized a new tellurotungstate(iv)-supported rhenium carbonyl derivative, Na₂H₂[(CH₃)₄N]₆[Te₂W₂₀O₇₀{Re(CO)₃}₂]·20H₂O (1). Additionally, compound 1 showed excellent catalytic activity in the selective epoxidation of alkenes under comparatively mild reaction conditions.

Facile Routes to Manganese(II) Triflate Complexes

Manganese(II) chloride reacts with trimethylsilyl triflate (TMS(OTf) where OTf = (-)OSO(2)CF(3)) in a 1:1 mixture of acetonitrile and tetrahydrofuran, and after recrystallization affords the linear coordination polymer [Mn(II)(CH(3)CN)(2)(OTf)(2)](n). Each distorted octahedral manganese(II) center in the polymeric chain has trans-acetonitriles and the remaining equatorial coordination positions are occupied by the bridging triflate anions. Dissolving [Mn(II)(CH(3)CN)(2)(OTf)(2)](n) in equal volumes of acetonitrile and pyridine followed by recrystallization with diethyl ether yields trans-[Mn(II)(C(5)H(5)N)(4)(OTf)(2)]. The distorted octahedral geometry of the manganese center features monodentate trans-triflate anions and four equatorial pyridines. Exposure of either [Mn(II)(CH(3)CN)(2)(OTf)(2)](n) or [Mn(II)(C(5)H(5)N)(4)(OTf)(2)] to water readily gives [Mn(II)(H(2)O)(6)](OTf)(2). XRD reveals hydrogen-bonding interactions between the [Mn(II)(H(2)O)(6)](2+) cation and the triflate anion. All three of these species are easily crystallized and provide convenient sources of manganese(II) for further synthetic elaboration.

catena-Poly[[bis(acetonitrile-kappaN)manganese(II)]-bis(mu-trifluoromethanesulfonato-kappa2O:O')]

The title compound, [Mn(CF(3)SO(3))(2)(CH(3)CN)(2)](n), has an Mn(II) cation on an inversion centre in an octahedral environment. The trifluoromethanesulfonate anions act as bridging ligands and form a one-dimensional coordination polymer in the direction of the a axis. The F atoms of the trifluoromethanesulfonate anions form layers parallel to the ab plane, but despite short intermolecular distances, no stabilizing F...F interactions are detected. The Mn-N and C-C bonds of the acetonitrile ligand are analyzed according to the Hirshfeld rigid-bond test. Renninger effects in the reflection data are considered, explored and discussed.

A diiron(IV) complex that cleaves strong C-H and O-H bonds

The controlled cleavage of strong C-H bonds like those of methane poses a significant challenge for chemists. In nature methane is oxidized to methanol by soluble methane monooxygenase via a diiron(IV) intermediate called Q. To model the chemistry of MMO-Q, an oxo-bridged diiron(IV) complex has been generated by electrochemical oxidation and characterized by several spectroscopic methods. This novel species has an Fe(IV/III) redox potential of +1.50 V vs. ferrocene (>2 V vs. NHE), the highest value thus far determined electrochemically for an iron complex. This species is quite an effective oxidant. It can attack C-H bonds as strong as 100 kcal mol(-1) and reacts with cyclohexane a hundred- to a thousand-fold faster than mononuclear Fe(IV)=O complexes of closely related ligands. Strikingly, this species can also cleave the strong O-H bonds of methanol and tert-butanol instead of their weaker C-H bonds, representing the first example of O-H bond activation for iron complexes.