Polyalkynylanthracenes – syntheses, structures and their behaviour towards UV irradiation

Abstract

A series of bis- and tris[(trimethylsilyl)ethynyl]anthracenes (1,5-, 1,8-, 9,10- and 1,8,10-) has been synthesised by multistep (cross coupling) reactions and the behaviour of the SiMe3-functionalised alkynylanthracene derivatives towards UV irradiation was qualitatively studied by NMR spectroscopy. In the case of 9,10-bis[(trimethylsilyl)ethynyl]anthracene we observed a photodimerisation upon UV irradiation; the third example was reported for a symmetrically 9,10-difunctionalised anthracene derivative, besides those with small fluorine- and methyl-substituents. The anthracene dimerisation is completely thermally reversible and the temperature dependence of the cycloelimination reaction was studied by (1)H VT-NMR experiments. The (deprotected) 1,5- and 1,8-diethynylanthracenes were converted with (dimethylamino)trimethylstannane to obtain the corresponding SnMe3-functionalised alkynes, potentially useful as highly conjugated building blocks in Stille cross coupling reactions. The new anthracene compounds were completely characterised by multinuclear NMR spectroscopy, (high resolution) mass spectrometry and - in most cases - by X-ray diffraction experiments.

1,8-Bis(phenylethynyl)anthracene – gas and solid phase structures

“…The shortest σ⋯π contact is found to be 2.57(1) Å between an anthracene hydrogen [at C(40)] and an alkyne carbon atom, accompanied by a distance to the second alkyne carbon atom at 2.71(1) Å. The variability of structural parameters of independent molecules for the same compound is also observable in the XRD results of 1,8-diethynylanthracene 10 8 In order to shed more light on the reason for the co-directional rotation of the phenylethynyl fragments in 1,8-BPEA, we studied first a simplified case with one substituent only: 1-(phenylethynyl)anthracene (1-PEA). 9).…”

“…In analogy to literature protocols, 8, 24 1,8-BPEA (1) was synthesized by a twofold Kumada cross-coupling reaction, using 1,8-dichloroanthracene and ( phenylethynyl)magnesium bromide, which was freshly prepared by conversion of phenylacetylene with ethylmagnesium bromide (Scheme 1).…”

“…8 Like the parent anthracene, these compounds undergo photodimerisation reactions upon UV irradiation. 8 Like the parent anthracene, these compounds undergo photodimerisation reactions upon UV irradiation.…”

Quantitative Structure–Retention Relationships for Polycyclic Aromatic Hydrocarbons and their Oligoalkynyl‐Substituted Derivatives

“…The unsubstituted PAHs as well as compounds 1b and 3b were purchased from Sigma-Aldrich whereas 4b was purchased from ABCR. Samples of 2b, [47,48] 2e, [49][50][51] 1c, [52] 1d, [52,53] 2c, [54] 2d, [54] 3c, [55,56] 3d, [55,56] and 4c [57] were prepared by following the approach as shown for the alkynyl-substituted anthracenes (Scheme 1, Supporting Information). Thus, the ethynyl-substituted anthracenes 2b and 2e were obtained by aN egishi-type coupling [58][59][60][61] of 9-bromoanthracene or 9,10-dibromoanthracene with ethynyltrimethylsilane (Scheme 1, step a) following ap rocedure by John and To ur.…”

Zweizähnige Bor‐Lewis‐Säuren und ihre Selektivität in der Wirt‐Gast‐Komplexbildung

“…Dazu stannylierten wir 1 quantitativ zum Distannan 2 (Schema 1). [32] Dieses reagierte hochselektiv und unter milden Bedingungen bei 0 8 8Cm it verschiedenen Chlorboranen unter Eliminierung von Chlortrimethylstannan.…”