A reinvestigation of tolane

Mavridis, Aristides; Moustakali‐Mavridis, I.

doi:10.1107/s0567740877011674

Cited by 87 publications

(39 citation statements)

References 12 publications

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“…All these values are comparable to those of salampy. The exocyclic C-C bond is short [1.45 (1) A] in agreement with the partial double-bond character of a formal single bond between an aromatic and a double bond (Mavridis & Moustakali-Mavridis, 1977;Ahmed, 1983). The double bond N=C= 1.27 (1) A has the usual value in this type of compound and does not merit special comment.…”

Section: By C Escobar and M T Garlandmentioning

confidence: 53%

Structure of 2-(4,6-dimethyl-2-pyridyliminomethyl)phenol, C14H14N2O

Escobar¹,

Garland²

1984

Acta Crystallogr C

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Section: By C Escobar and M T Garlandmentioning

confidence: 53%

Structure of 2-(4,6-dimethyl-2-pyridyliminomethyl)phenol, C14H14N2O

Escobar¹,

Garland²

1984

Acta Crystallogr C

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“…At ambient conditions, the crystal structure is monoclinic (P2 1 =a, C 5 2h ) with four molecules per unit cell (Z ¼ 4) [34,36,37]. The dimensions of the unit cell are a ¼ 12.778 Å , b ¼ 5.764 Å , c ¼ 15.508 Å and the angle is 113.39 according to [34] ( figure 1). The unit cell is asymmetrically composed two sets of two crystallographically independent molecules.…”

Section: Diphenylacetylene: Properties and Resultsmentioning

confidence: 99%

“…In the isolated molecule of DPA, the rotational barrier of the phenyl groups along the molecular axis is very small and the two phenyl groups are almost free to rotate around the two single bonds connecting them to the acetylenic moiety. The rotational barrier has been calculated to be 0.65 kcal mol À1 and this makes both the twisted and planar conformation energetically accessible [34]. In these conditions, the occurrence of a phase transition of the polyphenyl type would be tuned only by the intermolecular interactions.…”

Section: Diphenylacetylene: Properties and Resultsmentioning

confidence: 99%

“…This absorption is particularly significant because it is a definitive marker of the formation of saturated CH stretching (sp 3 ). According to Mavridis and Moustakali Mavridis [34] the shortest intermolecular distance at ambient pressure is 3.784 Å and involves the meta phenyl carbon of a molecule belonging to the set A and the meta phenyl carbon of a molecule belonging to the set B ( figure 1). Nevertheless, Robertson [29] reported four comparable shortest intermolecular distances ranging between 3.54 and 3.57 Å [36].…”

Section: Discussionmentioning

confidence: 99%

“…A line broadening is also observed with increasing pressure. All the data about the crystal cell are from [34].…”

Section: Ftirmentioning

confidence: 99%

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The high pressure reactivity of substituted acetylenes: a vibrational study on diphenylacetylene

Ceppatelli

Fontana²,

Citroni

2007

Phase Transitions

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This article is part of an extended study concerning the reactivity of acetylenic systems at high pressure and aims to the investigation of the high pressure synthesis and stabilization of polyacetylenic chains. The data for diphenylacetylene (DPA) are interpreted by establishing a comparison with the results obtained for acetylene, phenylacetylene, DPA and benzene. The room temperature high-pressure reaction of DPA was studied by means of Fourier Transform Infrared Spectroscopy (FTIR) and Raman spectroscopy using a membrane diamond anvil cell (MDAC). The appearance of the sp 3 C-H stretching absorption in the Infrared (IR) spectrum at about 9 GPa, indicates the formation of chemical bonds among the aromatic rings belonging to different DPA molecules. For higher pressures, the Raman data indicate the involvement of the internal CC moiety in the chemical transformation. Therefore, due to the steric hindrance of the phenyl rings, the pressure threshold for the reactivity of the two molecular fragments appears in this case to be reversed with respect to other molecular systems. The reaction smoothly occurs until the highest investigated pressure (26.6 GPa), and further proceeds on decompression. The recovered sample, deeply red coloured, was characterized by means of FTIR spectroscopy as an amorphous hydrogenated carbon containing locally ordered polymeric or oligomeric structures, where unreacted DPA molecules may be embedded.

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Structural Characterization of a Cyclohexamericmeta-Phenyleneethynylene Made by Alkyne Metathesis with In Situ Catalysts

Herrmann

et al. 2000

Angewandte Chemie

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Cyclophenyleneethynylenes (CPEs) have recently made a spectacular appearance as a novel class of carbon-rich supramolecular materials. [1, 2] Moore and co-workers have established meta-cyclophenyleneethynylenes (m-CPEs) [1±3] as tubular discotic liquid crystals [3d] and as porous, hydrogenbonded, channel-forming organic solids. [4] Channels in m-CPEs are formed through a combination of hydrogen bonds and the internal cavities of the hexagonally packed m-CPE. However only a low-quality single-crystal X-ray structure of this exciting CPE was obtained [4] and to our surprise, no highquality X-ray structures of m-CPE-derivatives are known. [2b, 5] In the past CPEs have been made by the Pd/Cu-catalyzed coupling of the Heck ± Sonogashira type. Substrates were either a preformed linear oligomer, [3] a half-cycle, [5] or 1-ethynyl-3-halo-substituted benzenes. [6] The latter compounds gave only very low yields of CPEs. Weiss et al., [7] Fürstner et al., [8] and our group [9] have reported that alkyne metathesis either with defined carbyne complexes [7,8] or with in situ catalysts, which are obtained from [Mo(CO) 6 ] and 4-chlorophenol in off-the-shelf 1,2-dichlorobenzene, [10,11] is an excellent method for preparing saturated and unsaturated ring systems. Herein, we report the synthesis of the new hexameric meta-cyclophenyleneethynylenes 2 a, b, d from dipropynylated benzenes 1 by alkyne metathesis as well as the isolation of the corresponding polymers 3 a ± d (Scheme 1). [12] The isolated m-CPE 2 a and its triosmiumdecacarbonyl complex 4 a have been characterized structurally by single-crystal X-ray diffraction analyses.The monomers 1 were prepared from the corresponding diiodides [12] by Pd-catalyzed propynylations. [10] Heating 1 a, [Mo(CO) 6 ], and either 4-chlorophenol or 4-trifluoromethylphenol in off-the-shelf 1,2-dichlorobenzene under a slow stream of nitrogen furnishes a mixture of oligomers and

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A reinvestigation of tolane

Cited by 87 publications

References 12 publications

Structure of 2-(4,6-dimethyl-2-pyridyliminomethyl)phenol, C14H14N2O

Structure of 2-(4,6-dimethyl-2-pyridyliminomethyl)phenol, C14H14N2O

The high pressure reactivity of substituted acetylenes: a vibrational study on diphenylacetylene

Structural Characterization of a Cyclohexamericmeta-Phenyleneethynylene Made by Alkyne Metathesis with In Situ Catalysts

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