The Synthesis and Properties of Face-to-Face Metallocene Polymers

Rosenblum, M.; Nugent, Helen M.; Jang, Ki-Deog; Labes, M. M.; Cahalane, W.; Klemarczyk, Philip; Reiff, W. M.

doi:10.1021/ma00122a046

Cited by 77 publications

(37 citation statements)

References 6 publications

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“…The twist of the naphthalene bridges, common to 1,8-bismetallocenylsubstituted naphthalenes, is caused by the repulsion of the two naphthalene-bonded Cp ligands. [11,13,14,15,17,19] The magnitude of the twist correlates roughly with the relative electron density on the naphthalene bonded Cp rings, which is demonstrated by the angle between the best planes of the Cp ligands. It is smallest for the dicationic species 1 and 3, 20.3 and 22.18, respectively, and increases for the neutral compounds 2 and 5.…”

Section: Molecular Structuresmentioning

confidence: 84%

“…Contributions to the research field of coupling mechanisms between paramagnetic sandwich compounds have been made for various types of complexes, [7] such as single metallocene and oligometallocene complexes, [8] which are linked directly, [9] through a saturated [10] or unsaturated bridge, [11] or are part of a cyclophane entity. [12] Recently, we reported the properties of a 1,8-bis(nickelocenyl)naphthalene, which showed antiferromagnetic coupling in the undiluted crystalline material.…”

Section: Introductionmentioning

confidence: 99%

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Electronic Coupling through Intramolecular π–π Interactions in Biscobaltocenes: A Structural, Spectroscopic, and Magnetic Study

Pagels¹,

Albrecht²,

Görlitz³

et al. 2011

Chemistry A European J

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The paramagnetic dinuclear complexes 1,8-bis(cobaltocenyl)naphthalene (2) and 1,8-bis[(pentamethyl-η(5)-cyclopentadienyl)(η(5)-cyclopentadiendiyl)cobalt(II)]naphthalene (4) were synthesized. The molecular structures were characterized by X-ray structure analysis and consisted of two cobaltocenes linked through a distorted naphthalene clamp. Electronic interactions between the two cobalt atoms were observed by cyclic voltammetric studies. Superconducting quantum interference device (SQUID) measurements of the pure compounds and diluted in their diamagnetic iron derivatives, as well as variable-temperature NMR spectroscopy experiments in solution are presented. Magnetic measurements revealed an antiferromagnetic coupling of the electrons in complexes 2 and 4. From NMR spectroscopy experiments, Curie behavior in the temperature range from -60 to +60 °C can be deduced. The electronic structure and magnetic behavior is supported by results of broken-symmetry DFT and multireference calculations along with UV/Vis spectroscopic data, which revealed an intramolecular through space π-π interaction between the cobaltocene units.

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Section: Molecular Structuresmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Electronic Coupling through Intramolecular π–π Interactions in Biscobaltocenes: A Structural, Spectroscopic, and Magnetic Study

Pagels¹,

Albrecht²,

Görlitz³

et al. 2011

Chemistry A European J

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“…[1][2][3] Recently, a new type of conjugated polymer that exhibits through-space interactions of pelectron systems has been developed. Poly(dibenzofulvene)s, 4-11 7,7-diarylnorbornane-containing conjugated polymers, 12,13 cyclophanecontaining polymers and face-to-face ferrocene polymers [36][37][38] have been synthesized, and their optical and electrochemical properties have been studied in detail. Polymers with layered aromatic rings and p-electron systems have also been investigated; [39][40][41][42][43][44][45][46][47][48][49][50][51][52][53] for example, Chen et al 53 recently reported the synthesis and formation of a twodimensional assembly of polymeric ladder phanes containing face-toface p-electron systems.…”

Section: Introductionmentioning

confidence: 99%

Naphthalene-based oligothiophene-stacked polymers

Morisaki

Fernandes

Chujo

2010

Polym J

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We report the synthesis and properties of p-stacked polymers consisting of oligothiophene and naphthalene as the stacked p-system and the scaffold, respectively. The titled polymers were obtained by the Suzuki-Miyaura coupling reaction. Oligothiophene units were layered in proximity, B3.0 Å from each other. Contribution of the quinoidal structure of the oligothiophene units involving the naphthalene scaffolds in the excited state resulted in relatively high photoluminescence quantum efficiencies. The polymers have potential application to optoelectronic devices such as hole-transporting materials. Polymer Journal (2010) 42, 928-934; doi:10.1038/pj.2010.101; published online 27 October 2010Keywords: conjugated polymers; p-stacked polymers; oligothiophene; redox polymers; synthesis INTRODUCTIONCommon conjugated polymers generally consist of sp-and/or sp 2 -carbon frameworks, and p-electrons are delocalized throughout the polymer backbone. Such conjugated polymers have attracted considerable attention because of their good processability and their readily tunable electronic and optical properties. [1][2][3] Recently, a new type of conjugated polymer that exhibits through-space interactions of pelectron systems has been developed. Poly(dibenzofulvene)s, 4-11 7,7-diarylnorbornane-containing conjugated polymers, 12,13 cyclophanecontaining polymers and face-to-face ferrocene polymers [36][37][38] have been synthesized, and their optical and electrochemical properties have been studied in detail. Polymers with layered aromatic rings and p-electron systems have also been investigated; 39-53 for example, Chen et al. 53 recently reported the synthesis and formation of a twodimensional assembly of polymeric ladder phanes containing face-toface p-electron systems. These polymers have potential applications in optoelectronic devices and single-molecular devices such as singlemolecular wires.Cofacially aligned p-electron systems have an important role in biochemistry and material chemistry; DNA has face-to-face base pairs stacked in the double-stranded main chains, 54 and the performance of organic optoelectronic devices strongly depends on the arrangement of the p-electron systems. 55 We have recently reported the synthesis of aromatic-ring-layered polymers using xanthene compounds as scaffolds. [40][41][42][43][44][45][46][47] [2.2] Paracyclophane-layered polymers, which mimic multilayered cyclophanes, 56-59 exhibited fluorescence resonance energy transfer from the layered paracyclophanes to the end-capping groups. The use of xanthene as a scaffold enabled us to introduce various aromatic compounds, such as phenylenes, 44 carbazoles, 45 thiophenes 46 and anthracene, 47 into the polymers, with the distance between the layered aromatic units being B4.5 Å . Our next target is to construct layered and p-stacked aromatic systems in proximity, less than the sum of the van der Waals radius (3.40 Å ) of an sp 2 -carbon, in the polymer backbone.

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“…The treatment of 1,8-diiodonaphthalene 39 with 1,1'-ferrocenyldizinc chloride 40 by Negishi coupling afforded polymer P18 with a relatively low M n of 3600 (Arnold et al, 1988). The synthetic procedure was modified as follows: the treatment of bis(2-octyl)ferrocene 43 with NaN(SiMe 3 ) 2 and FeCl 2 provided the ferrocene-stacked polymer P19 with an M n of 18400 (Nugent & Rosenblum, 1993;Rosenblum et al, 1995;Hudson et al, 1999). The addition of CoCl 2 and NiBr 2 instead of FeCl 2 yielded the corresponding ferrocene/cobaltocene-stacked and ferrocene/nickelocene-stacked polymers, respectively.…”

Section: Naphthalene-based Oligomers and Polymersmentioning

confidence: 99%