Dalton Transactions最新文献

Correction for 'Bimetallic polymerization of lactide with binaphthol-derived bis-heteroscorpionate dizinc and dimagnesium complexes' by Maxym Tansky et al., Dalton Trans., 2023, 52, 8784-8791, https://doi.org/10.1039/D3DT00592E.

In this manuscript, we report on the formation and isolation of the di-nuclear rhenium(VI) µ-oxido bridged complex {[ReOCl₂(L1)]}₂(µ-O) (1), which we nick-named "deep purple" due to its intense purple color both in the solid state as well as in solution, and its surprising catalytic activity in oxyanion reduction. Complex 1 was obtained as the unintended product in an attempt to synthesize oxidorhenium(V) complex [ReOCl(L1)₂], using the O,N-bidentate phenol-dimethyloxazoline ligand HL1, equipped with two electron-donating tert-butyl groups on the phenol ring. Single crystal X-ray diffraction analysis finally revealed the surprising µ-oxido structure of 1, with two paramagnetic Re(VI) centers and a mixed cis/trans-chlorido arrangement on the two Re centers. Via a targeted synthesis in cyclohexane at 60 °C under ambient conditions, high yields of over 90% of 1 were obtained. To explain the source of the highly stereoselective formation of 1, its formation was examined by DFT calculations at the B3LYP-D3BJ/dhf-TZVPP@B3LYP-D3BJ/dhf-SVP level of theory, with solvent effects included via the COSMO model. In contrast to isoelectronic µ-oxido bridged Mo(V) complexes, 1 proved to be highly active in catalytic oxyanion reduction, namely perchlorate and nitrate reduction. With a catalyst loading of 5 mol% of 1, a conversion of 90% was observed for perchlorate. These findings highlight that in rhenium chemistry, µ-oxido bridged complexes like 1 still show promising catalyst activities for oxyanion reduction and potentially also other redox transformations.

Correction for 'An aniline-bridged bis(pyrazolyl)alkane ligand for dizinc-catalysed ring-opening polymerization' by Pratyush K. Naik et al., Dalton Trans., 2024, 53, 17443-17447, https://doi.org/10.1039/D4DT02837F.

This study investigates the structural evolution of graphene oxide (GO), hydrothermally carbonized graphene oxide (HTC), and reduced graphene oxide (rGO), focusing on the effects of hydrothermal treatment durations (48 h and 72 h) on the electrochemical performance. GO samples exhibit crumpled, layered morphologies with wrinkled flakes due to oxygen functionalization, while thermal reduction to rGO results in restacked sheets and a more compact texture, indicating partial restoration of sp² domains. These structural changes enhance surface area, promote ion diffusion, and suggest improved suitability of the materials for supercapacitor electrode applications. Prolonged hydrothermal treatment increased functionalization, and subsequent thermal reduction in rGO samples selectively removed some oxygen groups, preserving redox-active sites and supporting improved electron transport. Cyclic voltammetry and galvanostatic charge-discharge analyses revealed that rGO@48 exhibited the highest specific capacitance (552.48 F g^-1 at 1 A g^-1) and best rate performance, attributed to its partially restored sp² carbon structure and preserved porosity. Electrochemical impedance spectroscopy confirmed low charge transfer resistance and favorable capacitive behavior for rGO@48, while rGO@72 showed the poorest performance due to restacking and limited ion diffusion. These findings indicate that a 48 h hydrothermal carbonisation followed by controlled reduction yields promising electrochemical properties for supercapacitor electrode application.

Synthesis and characterization of iron and nickel metal complexes employing the monodentate N-heterocyclic silylene RSiPh (R = PhC(N^tBu)₂) is reported. The iron complexes were obtained by reacting the 20 valence electron bis(η⁶-toluene)iron sandwich generated in situ by co-condensation of elemental iron and toluene vapor with the silylene ligand. The corresponding nickel complexes are accessible by employing bis(1,5-cyclooctadiene)nickel(0) as a zerovalent nickel source. The N-heterocyclic silylene RSiPh (R = PhC(N^tBu)₂) ligand was tethered in the periphery of bis(benzene)chromium, resulting in the formation of a unique bidentate organometallic pincer ligand with two independent silylene units bridged by a bis-benzene moiety. All complexes were fully characterized by multinuclear NMR spectroscopy, IR spectroscopy, mass spectrometry and a single-crystal X-ray analysis of one of the iron compounds. The results underscore the versatility of silylenes and demonstrate the utility of highly reactive bis(η⁶-toluene)iron as a single-step approach to zerovalent Fe-silylene complexes.