The Mono-, Di-, and Tri([5]trovacenyl)boranes: A Study of Intermetallic Communication Across an sp2-Hybridized Boron Atom

Elschenbroich, Christoph; Wolf, Matthias; Burghaus, Olaf; Harms, Klaus; Pebler, J.

doi:10.1002/(sici)1099-0682(199912)1999:12<2173::aid-ejic2173>3.0.co;2-0

Cited by 26 publications

(24 citation statements)

References 47 publications

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“… 23 The 17 valence-electron trovacene can be oxidized and reduced reversibly at E 1/2 = −0.23 V or E 1/2 = −3.04 V to generate a persistent cation and anion, respectively. 24 Further oxidation at ca. + 0.61 V occurs as two overlapping anodic peaks and results in rapid degradation to unknown products.…”

Section: Resultsmentioning

confidence: 99%

Cationic Cycloheptatrienyl Cyclopentadienyl Manganese Sandwich Complexes: Tromancenium Explored with High-Power LED Photosynthesis

et al. 2021

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In this contribution, we revisit the neglected and forgotten cationic, air-stable, 18-valence electron, heteroleptic sandwich complex (cycloheptatrienyl)(cyclopentadienyl)manganese, which was reported independently by Fischer and by Pauson about 50 years ago. Using advanced high-power LED photochemical synthesis, an expedient rapid access to the parent complex and to functionalized derivatives with alkyl, carboxymethyl, bromo, and amino substituents was developed. A thorough study of these “tromancenium” salts by a range of spectroscopic techniques ( 1 H/ 13 C/ 55 Mn-NMR, IR, UV–vis, HRMS, XRD, XPS, EPR), cyclic voltammetry (CV), and quantum chemical calculations (DFT) shows that these manganese sandwich complexes are unique metallocenes with quite different chemical and physical properties in comparison to those of isoelectronic cobaltocenium salts or (cycloheptatrienyl)(cyclopentadienyl) sandwich complexes of the early transition metals. Electrochemically, all tromancenium ions undergo a chemically partially reversible oxidation and a chemically irreversible reduction at half-wave or peak potentials that respond to the substituents at the Cp deck. As exemplarily shown for the parent tromancenium ion, the product generated during the irreversible reduction process reverts at least partially to the starting material upon reoxidation. Quantum-chemical calculations of the parent tromancenium salt indicate that metal–ligand bonding is distinctly weaker for the cycloheptatrienyl ligand in comparison to that of the cyclopentadienyl ligand. Both the HOMO and the LUMO are metal and cycloheptatrienyl-ligand centered, indicating that chemical reactions will occur either metal-based or at the seven-membered ring, but not on the cyclopentadienyl ligand.

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Section: Resultsmentioning

confidence: 99%

Cationic Cycloheptatrienyl Cyclopentadienyl Manganese Sandwich Complexes: Tromancenium Explored with High-Power LED Photosynthesis

et al. 2021

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“…Within this particular class of compounds, boranediyl‐bridged poly(ferrocenylene)s ( II , Scheme ) are of paramount interest because the three‐coordinate boron spacer offers a vacant p orbital for conjugative interaction with the cyclopentadienyl π‐systems. Boranediyl bridges should therefore be capable of mediating electronic interactions between the iron centers very efficiently 6. 7 The degree of electronic communication via the boron atom can be fine‐tuned by modifying the π‐donor ability of its substituent R, thereby offering a way for the rational design of novel materials with potentially useful electronic properties.…”

Section: Methodsmentioning

confidence: 99%

A Synthetic Route to Borylene‐Bridged Poly(ferrocenylene)s

et al. 2006

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Iron chains: The highly soluble, ferrocene‐containing polymer [‐fc‐B(Mes)‐]n (fc=Fe(C5H4)2, Mes=mesityl), with an average chain length of about 16 repeat units (n=16), is readily accessible by a novel polycondensation reaction starting from fc(BBr2)2 and HSiEt3 (see scheme). The polymer contains three‐coordinate boron centers, which are well‐suited for the promotion of electron delocalization along the polymer chain.

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“…Successively, [5]trovacenyl units were connected with different spacers: boron [244], silicon [245] and tin [246], a carbonyl group [247], methylene, ethylene and various groups with double bonds [248], triple bonds and extensively conjugated triple bonds [249] to the most recent, octamethylferrocene-1,1 -diyl [250]. Up to four [5]-trovacenyl groups were assembled into a benzene ring [251].…”

Section: -Coordinated Vanadium Speciesmentioning

confidence: 99%