[1.1]Diborataferrocenophane: A Highly Efficient Li⁺ Scavenger

Abstract

Ein nacktes Lithiumkation wird durch das [1.1]Diborataferrocenophan‐Dianion [1]2− effizient komplexiert und durch elektrochemische Oxidation der Ferrocen‐Einheit wieder freigesetzt. Mit der Synthese und Charakterisierung des Komplexes [1‐Li]Li([12]Krone‐4)2 gelang der erste experimentelle Nachweis eines theoretisch vorhergesagten Ferrocen⋅⋅⋅Li+‐Komplexes, in dem das Li+‐Ion lateral an das Eisenatom gebunden ist.

Selective Metal‐Cation Recognition by [2.2]Ferrocenophanes: The Cases of Zinc‐ and Lithium‐Sensing

“…However, after the addition of the Li + cation (1 equiv), a well-defined spectrum is obtained that exhibits four multiplets in a 4:4:4:4 ratio that correspond to the ferrocene protons. Similarly, the 13 C NMR spectrum shows important changes upon complexation: The four doublets corresponding to the methine carbon atoms of the ferrocene moiety connected to the phosphorus atoms [d = 74.4 (d, 7 Li NMR spectrum upon addition of receptor 4 to a solution of Li + salt, with a shift of Dd = 0.15 ppm (from d = 3.13 to 3.28 ppm; Figure 8b). The 31 P NMR spectrum of receptor 4 at 25 8C displays one signal at d = 27.1 ppm, which is shifted downfield to d = 30.2 ppm (Dd = 3.1 ppm) after complex forma- P NMR spectrum of the preformed complex 4·Li was recorded at À62 8C, two peaks at d = 22.9 and 31.7 ppm were observed.…”

“…The optical spectrum of the resulting solution was the same as that obtained by the dielectronic oxidation of the free receptor 4 to 4 2 + , which suggests that decomplexation of the Li + ion occurs during the electrochemical oxidation (see the Supporting Information). The complexation process of receptor 4 with Li + cations was also assessed by using 1 H, 13 C, 31 P, and 7 Li NMR spectroscopy, both in solution and in the solid state. Important changes were found upon complexation by all techniques, which is clear experimental proof for the existence of a planetary system for ferrocene-Li + complexes without negative charges on the bridge.…”

“…In all cases important differences were found between the lithium salt (C 6 H 5 ) 4 B À Li + in the presence and absence of the receptor 4. Thus, the 7 Li NMR spectrum of the (C 6 H 5 ) 4 B À Li + salt exhibits a signal composed of three partially superimposed peaks at d = À1.24, À1.67, and À2.54 ppm that changes to a single broad peak centered at d = 0.59 ppm upon complexation (Figure 9b). The solid-state 31 P NMR spectrum of the complex also shows two peaks at d = 36.2 and 17.7 ppm (Figure 9a).…”

Photoinduced FeCp Bond Cleavage and Insertion Reactions of Strained Silicon‐ and Sulphur‐Bridged [1]Ferrocenophanes in the Presence of Transition‐Metal Carbonyls

“…[20] Since the X-ray crystal structure of the first [1.1]ferrocenophane was reported by Watts et al in 1967, [52] such species have attracted significant attention, owing to their unusual structural and redox properties. [53] Analogous [1.1]ferrocenophanes bearing ER x bridging groups, in which E ranges from Group 13 (B, [54] Al, Ga, In [55] ), Group 14 (C [56] Si, [53,57] Sn [19] ) to Group 15 (P [58,59] ), have also been published and their properties extensively studied. Nonetheless, to the best of our knowledge, compound 10 is the first example of a Group- 16- [54,59] It has been previously noted that, in general, the greater the ring-strain in [1]ferrocenophanes, the more upfield shifted the ipso-Cp-C 13 C resonance.…”

Synthesis and structures of some di- and triferrocenylmethane derivatives

“…Some derivatives were reported between 1962 and 1973; however, the analytical data published are restricted to elemental analyses and in some cases to 1 H NMR spectra [6][7][8]. Interesting derivatives are ferrocenylboranes published by Wrackmeyer and coworkers [9] and Wagner and coworkers [10][11][12]. In the context of multiply bridged ferrocenes with the ultimate goal of a synthesis of 3 and derivatives thereof we are particularly interested in derivatives, which are functionalized at the opposite cyclopentadienyl ligands.…”