Organometallic Chemistry of Polypyridine Ligands I

Sadimenko, Alexander P.

doi:10.1016/s0065-2725(06)93004-9

Cited by 8 publications

(1 citation statement)

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“…32 ''Rollover'' cyclometalation is historically connected with the enormously popular 2,2 0 -bipyridine (bipy) ligand that was described by Blau already in 1888 33,34 and which, over the ensuing decades, has attracted growing interest. [35][36][37][38][39][40][41][42] Actually, a review article was even entitled ''Bipyridine: The Most Widely Used Ligand'' 36 and also chiral derivatives of 2,2 0 -bipyridine were developed. 43,44 The attractiveness of this ligand is certainly a consequence of i) its rich and intriguing coordination chemistry, ii) the easiness of functionalization of the pyridine rings and iii) the high stability of many of its transition-metal complexes against moisture and oxygen.…”

Section: Introductionmentioning

confidence: 99%

“Rollover” cyclometalation – early history, recent developments, mechanistic insights and application aspects

2012

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''Rollover'' cyclometalation constitutes a special case among the well-known class of cyclometalation reactions. An overview is given that covers the very first description of this reaction type, as well as recent developments. In addition, not only condensed-phase experiments are reviewed, but also investigations based on mass spectrometric techniques, together with ''in silico'' studies using DFTbased calculations are considered. While the latter two methods allow for a detailed analysis of the intrinsic factors that affect the reaction mechanisms, consideration of all three regimes permits to develop a coherent mechanistic picture and to address the often noted gap between condensed-and gasphase studies. Moreover, the quite unexpected reactivity of ''rollover'' cyclometalated complexes in gasphase experiments, as well as potential applications, e.g. in synthetic procedures, are discussed in some detail.

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Section: Introductionmentioning

confidence: 99%

“Rollover” cyclometalation – early history, recent developments, mechanistic insights and application aspects

2012

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Reductive Coupling of (Fluoro)pyridines by Linear 3d‐Metal(I) Silylamides of Cr–Co: A Tale of C−C Bond Formation, C−F Bond Cleavage and a Pyridyl Radical Anion

Müller

Werncke

2021

Chemistry A European J

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Herein, we disclose the facile reduction of pyridine (and its derivatives) by linear 3d‐metal(I) silylamides (M=Cr–Co). This reaction resulted in intermolecular C−C coupling to give dinuclear metal(II) complexes bearing a bridging 4,4′‐dihydrobipyridyl ligand. For iron, we demonstrated that the C−C coupling is reversible in solution, either directly or by reaction with substrates, via a presumed monomeric metal(II) complex bearing a pyridyl radical anion. In the course of this investigation, we also observed that the dinuclear metal(II) complex incorporating iron facilitated the isomerisation of 1,4‐cyclohexadiene to 1,3‐cyclohexadiene as well as equimolar amounts of benzene and cyclohexene. Furthermore, we synthesised and structurally characterised a non‐3d‐metal‐bound pyridyl radical anion. The reactions of the silylamides with perfluoropyridine led to C−F bond cleavage with the formation of metal(II) fluoride complexes of manganese, iron and cobalt along with the homocoupling or reductive degradation of the substrate. In the case of cobalt, the use of lesser fluorinated pyridines led to C−F bond cleavage but no homocoupling. Overall, in this paper we provide insights into the multifaceted behaviour of simple (fluoro)pyridines in the presence of moderately to highly reducing metal complexes.

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