Browsing by Author "Ringenberg, Mark R."

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    Control of molecular packing in crystal and electron communication of two ferrocenyl moieties across chiral isomannide or isosorbide bridge
    (2023) Zullo, Valerio; Guo, Tianao; Iuliano, Anna; Ringenberg, Mark R.
    Intramolecular electronic communication between electrochemically active groups connected by a bridging moiety can be modified through small changes in the spatial disposition of the redox active moieties and/or by the nature of the central core. In this study, chiral bio-based compounds, namely isomannide and isosorbide, were employed as cheap and easy-to-functionalize chiral scaffolds to bridge two ferrocenyl electroactive moieties. The crystal structures of both bis-ferrocenyl diester complexes were studied and they showed that the chirality of the bridge results in an open or tight helical crystal packing. The electron communication between the two electroactive units in the mixed valent monocations was also investigated using electrochemistry (cyclic voltammetry and differential pulsed voltammetry), and spectroelectrochemistry in the UV-Vis NIR. A computational study through time-dependent DFT was also employed to gain greater insight into the results obtained.
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    A ditopic phosphane‐decorated benzenedithiol as scaffold for di‐ and trinuclear complexes of Group‐10 metals and gold
    (2020) Schlindwein, Simon H.; Sibold, Carlo; Schenk, Mareike; Ringenberg, Mark R.; Feil, Christoph M.; Nieger, Martin; Gudat, Dietrich
    The ability of 3‐(diphenylphosphinomethyl)‐benzene‐1,2‐dithiol (pbdtH2) to act as ditopic ligand was probed in reactions with selected group‐10‐metal complexes. Reactions with [(cod)PdCl2] afforded a mixture of products identified as [Pd(pbdtH)2], [Pd2(μ2‐pbdt)2] and [Pd3(μ2‐pbdt)2Cl2]. The polynuclear complexes could be isolated after suitably adjusting the reaction conditions, and heating of a mixture in a microwave reactor effected partial conversion into a further complex [Pd3(μ2‐pbdt)3]. Reaction of pbdtH2 with [Ni(H2O)6Cl2] gave rise to a complex [Ni2(μ2‐pbdt)2], which was shown to undergo two reversible 1e-‐reduction steps. Reaction of [Pd(pbdtH)2] with [Au(PPh3)Cl] afforded heterotrinuclear [PdAu2(μ2‐pbdt)2(PPh3)]. All complexes were characterized by analytical, spectroscopic and single‐crystal X‐ray diffraction studies. Their molecular structures confirm the ability of the pbdt2- unit to support simultaneous P,S‐ and S,S‐chelating coordination to two metal centers.
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    Tetrazine chelate ligands bridging two [Ru(acac)2] fragments : mixed valency and radical complex formation
    (2022) Kaim, Wolfgang; Löw, Isabell; Ringenberg, Mark R.; Schwederski, Brigitte; Filippou, Vasileios; Fiedler, Jan
    Using bis(3‐methyl‐2‐pyridyl)‐1,2,4,5‐tetrazine 1, 3‐(2‐pyrimidyl)‐6‐methyl‐1,2,4,5‐tetrazine 2 and bis(2‐pyrimidyl)‐1,2,4,5‐tetrazine=bmtz as ligands, the complexes 3=[Ru(acac)2(1)], 4={[Ru(acac)2]2(1)], 5={[Ru(acac)2]2(bmtz)], and 6={[Ru(acac)2]2(2)] were prepared and identified by structure analysis of crystallized material. The one‐electron oxidized form 6(PF6) was also studied structurally, suggesting a Class II mixed‐valent situation. The neutral dinuclear systems exhibit two reversible oxidation processes with comproportionation constants 109.2