Bridged ferrocenes

Barr, T.H.; Watts, William E.

doi:10.1016/s0022-328x(00)86337-8

Cited by 44 publications

(7 citation statements)

References 18 publications

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“…The Cp-ring tilt can also be evaluated by examining the λ max values of the individual monomers; specifically, λ max values typically undergo bathochromic shifts with increasing Cp-ring tilt. , For example, Tilley's highly tilted 2 exhibits a λ max value at 470 nm, while ferrocene and 1,1‘-dimethylferrocene show λ max at 440 and 437 nm, respectively. , Similarly, the slightly ring-tilted monomer 3 exhibits a λ max at 444 nm, which is slightly red-shifted from those of ferrocene and 1,1‘-dimethylferrocene but blue-shifted from that of Tilley's monomer 2 . From these data, one can infer that monomer 3 possesses some degree of ring tilt strain but less than that of 2 , which is consistent with the X-ray data …”

Section: Resultsmentioning

confidence: 99%

Synthesis and Ring-Opening Metathesis Polymerization of Aryl-Substituted 1,1‘-(1,3-Butadienylene)ferrocenes

2005

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The unsaturated aryl-substituted ferrocenophanes 1,1‘-(1-phenylbuta-1,3-diene-1,4-diyl)ferrocene and 1,1‘-(1-mesitylbuta-1,3-diene-1,4-diyl)ferrocene were synthesized and used to prepare high molecular weight conjugated polymers by ring-opening metathesis polymerization. X-ray crystal structures of the phenyl- and mesityl-substituted monomers showed substantial bond angle strain in the butadiene bridge. The monomers were readily polymerized upon exposure to a tungsten-based initiator to give high molecular weight polymers that were soluble in common organic solvents. UV/vis spectral analysis indicated that the aryl moieties gave rise to enhanced conjugation when compared to related alkyl-substituted ferrocene-containing polymers. The enhanced conjugation was further supported by electrochemical analysis. The thermal stability of the new ferrocene-containing polymers was similar to that of oligomeric poly(ferrocenylene), and the conductivities upon doping were on the order of 10-5 S cm-1.

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Section: Resultsmentioning

confidence: 99%

Synthesis and Ring-Opening Metathesis Polymerization of Aryl-Substituted 1,1‘-(1,3-Butadienylene)ferrocenes

2005

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“…In their study it was characterized by two weak bands around 325 nm and 440 found that oxidation processes involving binuclear dialkylnm, which are both attributed to d-d transitions. [31] Any amino-ferrocenes are complicated by amine oxidation as perturbation of the electronic structure of the ferrocenes, well as oxidatively induced protonation and deprotonation i.e. conjugation within a conjugated chain, should lead to processes.…”

Section: Nmr Spectroscopymentioning

confidence: 99%

Synthesis of Soluble 1,3-Bridged Ferrocene-Acetylene Polymers and the Divergent-Convergent Synthesis of Defined Oligomers

Plenio

Hermann

Leukel

1998

Eur. J. Inorg. Chem.

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A –CH2NMe2 group attached to ferrocene can be used as an ortho/ortho‐directing group to selectively synthesize 1,2,3‐substituted ferrocenes, which are used as starting materials for novel 1,3‐linked ferrocene polymers and oligomers. The Sonogashira coupling reaction of 1‐(I),2‐(CH2NMe2)‐ferrocene with HC≡CSiEt3 results in 1‐(C≡CSiEt3),2‐(CH2NMe2)‐ferrocene (1b), which – following an ortho‐lithiation/iodination sequence – is converted into 1‐(I),2‐(CH2NMe2),3‐(C≡CSiEt3)‐ferrocene (1d). Removal of the –SiEt3 protective group yields 1‐(I),2‐(CH2NMe2),3‐(C≡CH)‐ferrocene, which can be polymerized under Sonogashira conditions to yield a soluble, bimodal ferrocene‐acetylene polymer of MW = 3700/7100 and Mn = 4272. To understand the properties of the polymer better and to evaluate the effect of 1,3‐substitution on the electronic communication between the metal centers, a divergent‐convergent approach was used to synthesize defined di‐, tri‐ and tetranuclear ferrocenes. Accordingly, 1d was cross‐coupled with 1‐(CH2NMe2),2‐(C≡CH)‐ferrocene to give [2‐(CH2NMe2)‐ferrocene‐1‐yl]‐C≡C‐[2‐(CH2NMe2),3‐(C≡CSiEt3)‐ferrocene‐1‐yl] (2a). Removal of the protective group in 2a led to [2‐(CH2NMe2)‐ferrocene‐1‐yl]‐C≡C‐[2‐(CH2NMe2),3‐(C≡CH)‐ferrocene‐1‐yl] (2b), which was treated with [1‐(I),2‐(CH2NMe2)ferrocene‐3‐yl]‐C≡C‐[2‐(CH2NMe2),3‐(C≡CSiEt3)‐ferrocene‐1‐yl] (2c) to result in the corresponding tetrameric ferrocene (4a).

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“…The spectra for 1 and 4 also revealed broad absorptions near 360 and 470 nm resulting from symmetry-forbidden excitations of electrons from the d orbitals of iron. These absorptions, which are red-shifted relative to those of ferrocene, are characteristic of conjugated ferrocenyl moieties 2 ORTEP drawings (40% probability level) for 1 . …”

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confidence: 98%

Soluble Conjugated Polymers That Contain Ferrocenylene Units in the Backbone

1998

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We report the synthesis of a new ferrocenophane, 1,1′-(1-tertbutyl-1,3-butadienylene)ferrocene (1), and its successful polymerization to yield the first soluble conjugated polymer that contains repeat units of ferrocenylene in the backbone. Conjugated polymers that contain transition metals in the backbone have been targeted since the late 1950s because of their potential use as conducting, semiconducting, and/or optoelectronic materials. [1][2][3][4][5][6][7][8][9] Previous synthetic efforts have led, however, either to oligomeric materials that have poor electrical properties or to polymeric materials that are insoluble and intractable. [10][11][12] Oligomeric materials are less likely to exhibit the mechanical properties displayed by high molecular weight polymers, 13 and insoluble polymers cannot be readily processed because of difficulties in casting the materials into useful shapes and films. The approach reported here provides convenient solutions to both of these problems.Scheme 1 shows the synthesis of ferrocenophane 1 in two steps from 1,1′-(4-oxo-1-butenylene)ferrocene 14 (2). Alkylation of 2 with tert-butyllithium followed by dehydration afforded 1 in 43% overall yield. 14 Purification by column chromatography followed by recrystallization from hexane gave large red needles of 1 that are stable in air and soluble in common organic solvents such as benzene, hexane, CH 2 Cl 2 , and THF.Ring-opening metathesis polymerization (ROMP) 16 of ferrocenophane 1 by the tungsten-based metathesis catalyst W(dNPh)-(dCHPh(2-OMe))(OC(CF 3 ) 2 (CH 3 )) 2 )(THF) 17 readily generated the conjugated polymer 4 (eq 1). 18 During the polymerizations, the initially red solutions became noticeably darker and more viscous. The resultant deep red polymers are soluble in common organic solvents such as benzene, CH 2 Cl 2 , and THF. These

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Bridged ferrocenes

Cited by 44 publications

References 18 publications

Synthesis and Ring-Opening Metathesis Polymerization of Aryl-Substituted 1,1‘-(1,3-Butadienylene)ferrocenes

Synthesis and Ring-Opening Metathesis Polymerization of Aryl-Substituted 1,1‘-(1,3-Butadienylene)ferrocenes

Synthesis of Soluble 1,3-Bridged Ferrocene-Acetylene Polymers and the Divergent-Convergent Synthesis of Defined Oligomers

Soluble Conjugated Polymers That Contain Ferrocenylene Units in the Backbone

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