Bridged hydrocarbyl or hydrocarbon binuclear transition metal complexes: classification, structures, and chemistry

Mixed-Valent Diiron μ-Carbyne, μ-Hydride Complexes: Implications for Nitrogenase

“…Compared to analogous data for the {Fe2(µ-H)}2 state of FeMoco (E4(4H)), the data and analysis presented herein suggest that the hydride ligands in E4(4H) bridge isovalent (most probably Fe III ) metal centers. Although electron transfer involves metal-localized orbitals, investigations of [(P6ArC)Fe2(µ-H)] +1 and [(P6ArC)Fe2(µ-H)] -1 by pulse EPR revealed that redox chemistry induces significant changes in Fe-C covalency (-50% upon 2 ereduction), a conclusion further supported by X-ray absorption spectroscopy, 57 Fe Mössbauer studies, and DFT calculations. Combined, our studies demonstrate that changes in covalency buffer against the accumulation of excess charge density on the metals by partially redistributing it to the bridging carbon, thereby facilitating multi-electron transformations.…”

Activation of propargylic alcohols by dimolybdenum tris(μ-thiolate) complexes: Influence of the substituents R in HCCCR2(OH)-vinylidene/allenylidene transformation. Reactivity of allenylidene complexes

“…Instead of the characteristic 1 H NMR resonance of the C b HR group in 13 at d 7.37, two protons were detected as a doublet (J H-H = 8.0 Hz) between 4 and 5 ppm, confirming that the hydride anion had added to the outer carbon atom (C b ) of the vinylidene group to give a new hydrocarbyl bridging compound. The 13 C NMR spectra of 14 displayed a typical l-alkylidyne signal at extreme low field (445.4 ppm) [29]. The equivalence of the Cp groups suggests that the alkylidyne bridge is symmetrically bonded to the two molybdenum atoms and that the p-Mo-C overlap required by electron-counting rules, is delocalised through the Mo-C-Mo bridge.…”

The co-crystal tetraaquabis(2-oxido-3,5-dinitrobenzoato)bis(2-oxido-3,5-dinitrobenzoic acid)tricopper–diaquabis(2-hydroxy-3,5-dinitrobenzoato)(2-oxido-3,5-dinitrobenzoic acid)copper–water (0.54/0.92/4): a reformulation?

“…The structures and properties of multinuclear complexes have attracted much scientific attention, due to their potentially useful electronic or magnetic properties (Holton et al, 1983). As part of our investigations of multinuclear complexes (Su & Xu, 2005), the title compound, (I) (Figs.…”