Cobalt Complexes Containing Dimethyldihydropyrene-Substituted Cyclobutadiene Ligands

Zhang, Pengrong; Brkić, Zinka; Berg, David J.; Mitchell, Reginald H.; Oliver, Allen G.

doi:10.1021/om200575t

Cited by 9 publications

(8 citation statements)

References 37 publications

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“…All the carbons on the DHP framework are close to the mean plane with an average deviation of 0.028 Å. The average C–C distances in the DHP framework are 1.402 Å (Table ) with the sum of the modulus of bond deviation from average being 0.307 Å, somewhat less than that (0.361 Å) found for the cycloheptatriene 9 , which is consistent with the NMR data suggestion that tropone is less aromatic than cycloheptatriene!…”

Section: “Aromaticity” Data Based Upon 1h Nmr Spectrasupporting

confidence: 82%

Experimental Verification of the Homoaromaticity of 1,3,5-Cycloheptatriene and Evaluation of the Aromaticity of Tropone and the Tropylium Cation by Use of the Dimethyldihydropyrene Probe

et al. 2012

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By use of a dimethyldihydropyrene experimental probe for aromaticity, 1,3,5-cycloheptatriene (16) is demonstrated to be a neutral homoaromatic hydrocarbon! On the basis of (1)H NMR results, 16 is judged to be ~30%, tropone 18 ~20%, and tropylium 22 ~50% as aromatic as benzene. The latter result may be an underestimation because of charge delocalization. The B3LYP/6-31G* calculated geometries and GIAO-HF/6-31G*//B3LYP/6-31G* calculated NMR chemical shifts and nucleus-independent chemical shifts (NICS) support these conclusions. These estimates were obtained by synthesis of the annelated dihydropyrenes 7 (tropone fused), 9 (1,3,5-cycloheptatriene fused), and 10 (tropylium fused). [4 + 3] Cycloaddition of the isofuran 5 with an oxyallyl cation (prepared from 2,4-dibromopentan-3-one) gave the C7 fused dihydropyrene 6 in 77% yield. Elimination of water gave tropone 7 in 61% yield, which, via LiAlH(4) reduction to alcohol 8 (48% yield) and treatment with HBF(4), gave quantitatively tropylium cation 10. When ketone 7 was reduced with AlH(3) (generated from AlCl(3)/LiAlH(4)) in ether/benzene at 25 °C, the isomeric cycloheptatrienes 11 (70% yield) and 9 (15% yield) were obtained.

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Section: “Aromaticity” Data Based Upon 1h Nmr Spectrasupporting

confidence: 82%

Experimental Verification of the Homoaromaticity of 1,3,5-Cycloheptatriene and Evaluation of the Aromaticity of Tropone and the Tropylium Cation by Use of the Dimethyldihydropyrene Probe

et al. 2012

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“…In particular, with phenyl and 2-thienylcarbaldehyde groups at the starting alkyne (entry 3), a 10/1 ratio was observed by 1 H NMR. Only one regioisomer of 32 was isolated when using ferrocenyl-2-thienylcarbaldehyde acetylene as the starting material, albeit in moderate yield (entry 5) . Unfortunately, regioselectivity remained an issue in the other cases.…”

Section: Resultsmentioning

confidence: 92%

An Improved Protocol for the Synthesis of [(η⁴-C₄R₄)Co(η⁵-C₅H₅)] Complexes

et al. 2011

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International audienceThe reaction of bulky alkynes C2R2 with (η5-C5H5)Co(CO)(dimethyl fumarate) under microwave irradiation provides complexes of the type [(η4-C4R4)Co(η5-C5H5)] in good to excellent yields. This protocol represents a significant improvement over those reported previously. In particular, the formation of insertion products such as cyclopentadienones or cyclohexadienes can be avoided. In addition, because of the exceptional stability of (η5-C5H5)Co(CO)(dimethyl fumarate), the reactions can be carried out in crude solvents. The easy access to [(η4-C4R4)Co(η5-C5H5)] complexes stimulated a study of their reactivity, notably under cross-coupling conditions

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“…[12][13][14] Reversible photoisomerisation occurs between the closed DHP structure and the open and less p-conjugated cyclophanediene structure with an isomerisation ratio of almost 100%, [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] and this can switch the redox potential of DHP. 25 This reversible photoswitching of the redox potential makes DHP a promising molecular component in photochromic metal complexes [32][33][34][35][36][37][38] and photoswitching molecular devices. [39][40][41][42][43][44] In particular, the redox potential of DHP is very close to that of ferrocene, indicating that incorporating DHP into a p-conjugated molecular system would improve its electron transfer properties.…”

Section: Introductionmentioning

confidence: 99%

π-Conjugation modification of photochromic and redox-active dimethyldihydropyrene by phenyl- and ethynyl-terpyridines and Ru(bis-terpyridine) complexes

Muratsugu

Nishihara

2014

New J. Chem.

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p-Conjugation modification of photochromic and redox-active dimethyldihydropyrene by phenyland ethynyl-terpyridines and Ru(bis-terpyridine) complexes † Satoshi Muratsugu* ab and Hiroshi Nishihara* a Two p-conjugated dimethyldihydropyrene (DHP)-bis-terpyridine ligands (2 and 3) were prepared, in which two terpyridine moieties were connected at the 4 and 9 positions of DHP (1) via phenyl and ethynyl linkers, respectively. The nature of the p-conjugated linkers influenced the valence orbitals of the DHP moiety, which shifted the redox potentials of the DHP moiety and the absorption spectra. In 3 with an ethynyl linker, the redox potentials of the DHP moiety were shifted in the positive direction and the absorption band was largely red-shifted compared with 1. In 2 with a phenyl linker, the shifts in the redox potentials of the DHP moiety and in the absorption band were moderate. These results were supported by valence orbital energies calculated using time-dependent density functional theory, which enabled the assignment of the four main transitions in each spectrum for the first time.The fluorescence intensity of 3 was larger than that of 2, which was photoisomerisable. Two dinuclear Ru(bis-terpyridine) complexes (4 and 5) were prepared from 2 and 3, and their redox and photochemical properties were investigated.

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Cobalt Complexes Containing Dimethyldihydropyrene-Substituted Cyclobutadiene Ligands

Cited by 9 publications

References 37 publications

Experimental Verification of the Homoaromaticity of 1,3,5-Cycloheptatriene and Evaluation of the Aromaticity of Tropone and the Tropylium Cation by Use of the Dimethyldihydropyrene Probe

Experimental Verification of the Homoaromaticity of 1,3,5-Cycloheptatriene and Evaluation of the Aromaticity of Tropone and the Tropylium Cation by Use of the Dimethyldihydropyrene Probe

An Improved Protocol for the Synthesis of [(η⁴-C₄R₄)Co(η⁵-C₅H₅)] Complexes

π-Conjugation modification of photochromic and redox-active dimethyldihydropyrene by phenyl- and ethynyl-terpyridines and Ru(bis-terpyridine) complexes

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Cobalt Complexes Containing Dimethyldihydropyrene-Substituted Cyclobutadiene Ligands

Cited by 9 publications

References 37 publications

Experimental Verification of the Homoaromaticity of 1,3,5-Cycloheptatriene and Evaluation of the Aromaticity of Tropone and the Tropylium Cation by Use of the Dimethyldihydropyrene Probe

Experimental Verification of the Homoaromaticity of 1,3,5-Cycloheptatriene and Evaluation of the Aromaticity of Tropone and the Tropylium Cation by Use of the Dimethyldihydropyrene Probe

An Improved Protocol for the Synthesis of [(η4-C4R4)Co(η5-C5H5)] Complexes

π-Conjugation modification of photochromic and redox-active dimethyldihydropyrene by phenyl- and ethynyl-terpyridines and Ru(bis-terpyridine) complexes

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An Improved Protocol for the Synthesis of [(η⁴-C₄R₄)Co(η⁵-C₅H₅)] Complexes