Syntheses, structures and redox properties of {Os(PPh3)2Cp}2{μ-(CC)x} (x=2, 3, 4): Comparisons with the Ru analogues

The discovery of new classes of antibacterial agents, particularly those with unique biological targets, is essential to keep pace with emerging drug resistance in pathogenic bacteria. We identified the minimal structural component of the cyclic acyldepsipeptide (ADEP) antibiotics that exhibits antibacterial activity. We found that N-acyldifluorophenylalanine fragments function via the same mechanism of action as ADEPs, as evidenced by the requirement of ClpP for the fragments’ antibacterial activity, the ability of fragments to activate B. subtilis ClpP in vitro, and the capacity of an N-acyldifluorophenylalanine affinity matrix to capture ClpP from B. subtilis cell lysates. N-acyldifluorophenylalanine fragments are much simpler in structure than the full ADEPs and are also highly amenable to structural diversification. Thus, the stage has been set for the development of non-peptide activators of ClpP that can be used as antibacterial agents.

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“…The syntheses of complexes 2 ,8b 3 ,10b and 5 13 have been reported previously; those of the other two complexes follow.…”

Section: Resultsmentioning

confidence: 66%

A Simple Fragment of Cyclic Acyldepsipeptides Is Necessary and Sufficient for ClpP Activation and Antibacterial Activity

et al. 2014

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“…The syntheses, redox properties, molecular and electronic structures of metal complexes bearing linear, “all-carbon” ligands, [{L m M}(μ-C 4 ){ML m }] n + have been widely investigated since the first examples were synthesized in the mid 1970s . Among these investigations, the elucidation of the structure of the carbon-ligand and nature of the “mixed-valence” derivatives ( n = 1) as a function of the metal, M, and supporting ligands, L m , have been topics of considerable interest. − Four of the early examples of [{L m M}(μ-CCCC){ML m }] + complexes, specifically [{Cp*(dppe)Fe}(μ-CCCC){Fe(dppe)Cp*}] + ([ 1a ] + ) (Chart ), , [{Cp*(dppe)Ru}(μ-CCCC){Ru(dppe)Cp*}] + ([ 2a ] + ) (Chart ), [{Cp(PPh 3 ) 2 Ru}(μ-CCCC){Ru(PPh 3 ) 2 Cp}] + , and [{Cp*(NO)(PPh 3 )Re}(μ-CCCC){Re(PPh 3 )(NO)Cp*}] + , have become established as benchmark examples of highly delocalized or Class III mixed-valence complexes. Each complex is comprised of a buta-1,3-diyn-1,4-diyl fragment terminated by half-sandwich, d 6 metal fragments and exhibits characteristic ν(CC) and NIR spectra.…”

Section: Introductionmentioning

confidence: 99%

Iron versus Ruthenium: Clarifying the Electronic Differences between Prototypical Mixed-Valence Organometallic Butadiyndiyl Bridged Molecular Wires

et al. 2018

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The electronic structures of the prototypical bimetallic buta-1,3-diyn-1,4-diylbridged radical cation complexes [{M(dppe)Cp´} 2 (µ-C≡CC≡C)] + (M= Fe, Cp´ = Cp* (1a), Cp (1b); M = Ru, Cp´ = Cp* (2a), Cp (2b)) have been (re-)investigated using a combination of UV-vis-NIR and IR spectroelectrochemistry, and quantum chemical calculations based on both dispersion-corrected global (BLYP35-D3) and local (Lh-SsirPW92-D3) hybrid functionals. Following analysis of new and existing data, including the IR-active ν(C≡C) bands, the iron compounds [1] + are reclassified as valence-trapped (Robin and Day Class II) mixed-valence complexes, in contrast to the ruthenium complexes [2] + , which are delocalized (Robin and Day Class III) systems. All members of the series exist as a thermally populated distribution of conformers in solution, and the overlapping spectroscopic profiles make the accurate extraction of the parameters necessary for the analysis of [1] + and [2] + within the framework of the Marcus-Hush model extremely challenging. Analysis of the spin-density distributions from a range of conformational minima provides an alternative representation of

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“…[119,120] In contrast, trialkylsilyl (the most often TMS) protected derivatives are easy in preparation and handling and are broadly used for that pur-pose. Thus, iron(II), [124] ruthenium(II), [98,125] osmium(II), [126] and platinum(II) [127] end-capped polyynes were obtained with an addition of fluoride ions source. [121,122] Preparation and full characterization of these species includes X-ray single diffraction structures of polyyndiylides Ag 2 C 6 and Ag 2 C 8 described by Mak.…”

Section: Transition Metal End-capped Polyynesmentioning

confidence: 99%

Reactivity of Polyynes: Complex Molecules from Simple Carbon Rods

2019

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Polyynes are linear carbon rods that may be regarded as models of carbyne – still elusive linear allotropic form of carbon. This microreview addresses the use of polyynes as synthetic precursors of complex organic and organometallic compounds. Application of such unusual molecules as starting materials for various chemical transformations leads to products which often are not easily accessible using “traditional“ approaches. Polyynes may for instance be used in the synthesis of molecular wires, materials possessing high nonlinear optical response, complex donor–acceptor systems, solvatochromic fluorescent dyes or natural products. The most significant challenge here is to control the regioselectivity of a transformation of such linear sp‐hybridized carbon chains. The impact of steric and electronic properties of reagents on the reaction pattern is hence highly important and will be discussed. Moreover, the transformations of end‐groups will also be addressed since their reactivity might very often be different than that of acetylenes.

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Syntheses, structures and redox properties of {Os(PPh3)2Cp}2{μ-(CC)x} (x=2, 3, 4): Comparisons with the Ru analogues

Cited by 25 publications

References 44 publications

A Simple Fragment of Cyclic Acyldepsipeptides Is Necessary and Sufficient for ClpP Activation and Antibacterial Activity

A Simple Fragment of Cyclic Acyldepsipeptides Is Necessary and Sufficient for ClpP Activation and Antibacterial Activity

Iron versus Ruthenium: Clarifying the Electronic Differences between Prototypical Mixed-Valence Organometallic Butadiyndiyl Bridged Molecular Wires

Reactivity of Polyynes: Complex Molecules from Simple Carbon Rods

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