Selective polymerization of double bonds in 1,5-bis(trimethylsilyl)-3-methylenepentadiyne and 1,5-bis(trimethylsilyl)-3-(2-propylidene)pentadiyne

Alberts, Albert H.

doi:10.1021/ja00190a069

Cited by 19 publications

(15 citation statements)

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“…Alberts had found that linearly-conjugated trans-l,6-bis(trimethylsilyl)-hex-3-ene-1,5-diyne was more stable than the cross-conjugated isomer, 1,5-bis(trimethylsilyl)-3-methylidenepenta-l,4-diyne [34]. In the case of the studied TEEs, however, a similar trend was not observed.…”

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confidence: 80%

Donor/Acceptor‐Substituted Tetraethynylethenes: Systematic Assembly of Molecules for Use as Advanced Materials

Tykwinski¹,

Schreiber²,

Carlón³

et al. 1996

Helvetica Chimica Acta

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A comprehensive series of tetraethynylethenes ( = 3,4-diethynyIhex-3-ene-l,S-diynes, TEEs) bearing electrondonating (p-methoxyphenyl or p-aminophenyl) and/or electron-accepting (p-nitrophenyl) groups was prepared via [I'd]-catalyzed Sonogashira cross-coupling reactions. The electronic and photonic properties of these molecules were investigated with a special emphasis on the effects caused by degree and pattern of donor/acceptor substitution around the central TEE core. This analysis showed that intramolecular donor-acceptor interactions, as evidenced by a long-wavelength charge-transfer band, are considerably more effective in TEES 44 and 46, with trans and cis, linearly-conjugated electronic pathways between donor and acceptor, than in 11, with a geminal, cross-conjugated electronic pathway. UVjVIS Spectroscopy revealed a steady bathochromic shift of the longestwavelength absorption band (Amax) as the number of donor-acceptor conjugation paths increased upon changing from his-arylated (11, 44, and 46) to tetrakis-arylated (14, 31, and 35) TEEs. The position of the longest-wavelength absorption was also found to be strongly dependent on the nature of the N-substituents in the R,NC,H,-donor groups. Electronic emission spectroscopic investigations demonstrated a considerable solvent dependency of the fluorescence of donor-acceptor-substituted TEES such as 11 or 44, in agreement with the presence of highly polarized excited states in these molecules. Correspondingly, fluorescence spectra of TEES bearing only donor or acceptor substituents showed little solvent dependency. The large majority of the donor/acceptor-substituted TEEs are thermally and environmentally stable molecules. They can be stored for months as solids in the air at room temperature, and many decompose only upon heating to temperatures above 200°. X-Ray analysis showed the conjugated C-atom scaffolds of 44, 46, and 67 to be essentially planar, whereas the aryl substituents in 28 and 30 are rotated out of the plane of the TEE core by varying degrees. 1.Introduction. -Conjugated organic molecules and polymers show great promise as components for advanced electronic and photonic applications [ 1-31. For the rational design of tailor-made organic materials with specific function, it is necessary to develop a profound understanding of how and to what degree changes in molecular electronic structure affect physical properties [4].Tetraethynylethene ( = 3,4-diethynylhex-3-ene-l,5-diyne, TEE 1) provides a unique C-atom framework for the incorporation of functional groups into planar, fully conjugated, two-dimensional n -chromophores [5-81. Essentially every desired substitution pattern on the TEE core can be achieved through the proficient use of various (trialkylsily1)alkyne-protecting groups. Together, these molecules make up a 'molecular construction kit' which has been readily elaborated into acyclic [9] and cyclic [lo] acetylenic molecular scaffolding, formation of oligomers [9] and polymers [l 11 with the conjugated poly(triacety1ene) backbone, a...

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Donor/Acceptor‐Substituted Tetraethynylethenes: Systematic Assembly of Molecules for Use as Advanced Materials

Tykwinski¹,

Schreiber²,

Carlón³

et al. 1996

Helvetica Chimica Acta

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“…Cross-conjugation is defined as the conjugation between two unsaturated π-segments that, although not conjugated to each other, are conjugated to an intervening unsaturated segment . The synthesis of geminal -diethynylethene ( gem -DEE, Chart ) was pioneered by Böhm-Gössl et al, Alberts et al, and Gleiter et al and further refined and elaborated by the laboratories of Diederich and Tykwinski. − Efforts by the latter enable facile preparation of gem -DEE and its use as the building block for intricate carbon-rich scaffoldings, while also providing a rich source of ligands for metal-alkynyl chemistry.…”

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confidence: 99%

A Synthetic Approach to Cross-Conjugated Organometallic Complexes Based on geminal-Diethynylethene and Co^III(cyclam)

et al. 2016

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A series of CoIII(cyclam) complexes ([1a,b]Cl, [2a–c]PF6, [3]Cl2, [4a](OTf)4, [4b](PF6)2, and [5]Cl2) (cyclam = 1,4,8,11-tetraazacycloctetradecane) bearing a geminal-diethynylethene ligand (gem-DEE) is reported. Syntheses of these acyclic cross-conjugated complexes were accomplished in satisfactory yields, and structural characterizations established that the geometrical feature of gem-DEE is largely preserved upon metalation. Combined structural and electrochemical studies suggest that the gem-DEE ligand, as a σ-donor, is weaker than phenylethynyl but stronger than butadiynyl in CoIII(cyclam) complexes. Voltammetric analysis indicated a weak but discernible Co–Co coupling across the gem-DEE bridge in [3]Cl2 and [4a](OTf)4, while the addition of a second acetylide in the trans position diminished such coupling in [4b](PF6)2. DFT analysis revealed significant dπ–π mixing around the cobalt centers with extended π-overlap in the highest occupied orbitals and substantial σ-based mixing in the lowest unoccupied orbitals of [3]Cl2 and [4a](OTf)4, the latter of which likely contributes to the weak Co–Co coupling.

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“…Early synthesis of unsubstituted gem -diethynylethene was pioneered by Böhm-gössl et al in 1963, utilizing a nucleophilic addition of but-3-yn-2-one (or penta-1,4-diyne) with ethynylmagnesium bromide (or methylmagnesium bromide) followed by dehydration . In a similar manner, Alberts later applied the nucleophilic addition of ethyl acetate with lithium acetylide . These reports were restricted to limited and specific substrates, and over-stoichiometric amounts of metal waste were generated (Scheme a).…”

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Nickel-Catalyzed 3,3-Dialkynylation of 2-Aryl Acrylamides: Direct Access to gem-Diethynylethenes via Double Vinylic C–H Bond Activation

Zhao

Han

et al. 2021

Org. Lett.

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Selective polymerization of double bonds in 1,5-bis(trimethylsilyl)-3-methylenepentadiyne and 1,5-bis(trimethylsilyl)-3-(2-propylidene)pentadiyne

Cited by 19 publications

References 0 publications

Donor/Acceptor‐Substituted Tetraethynylethenes: Systematic Assembly of Molecules for Use as Advanced Materials

Donor/Acceptor‐Substituted Tetraethynylethenes: Systematic Assembly of Molecules for Use as Advanced Materials

A Synthetic Approach to Cross-Conjugated Organometallic Complexes Based on geminal-Diethynylethene and Co^III(cyclam)

Nickel-Catalyzed 3,3-Dialkynylation of 2-Aryl Acrylamides: Direct Access to gem-Diethynylethenes via Double Vinylic C–H Bond Activation

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Selective polymerization of double bonds in 1,5-bis(trimethylsilyl)-3-methylenepentadiyne and 1,5-bis(trimethylsilyl)-3-(2-propylidene)pentadiyne

Cited by 19 publications

References 0 publications

Donor/Acceptor‐Substituted Tetraethynylethenes: Systematic Assembly of Molecules for Use as Advanced Materials

Donor/Acceptor‐Substituted Tetraethynylethenes: Systematic Assembly of Molecules for Use as Advanced Materials

A Synthetic Approach to Cross-Conjugated Organometallic Complexes Based on geminal-Diethynylethene and CoIII(cyclam)

Nickel-Catalyzed 3,3-Dialkynylation of 2-Aryl Acrylamides: Direct Access to gem-Diethynylethenes via Double Vinylic C–H Bond Activation

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A Synthetic Approach to Cross-Conjugated Organometallic Complexes Based on geminal-Diethynylethene and Co^III(cyclam)