Synthesis, Electronic Spectra, and Crystal Structural Properties of Fluorinated [3₃](1,3,5)cyclophanes

Abstract

[structure: see text] Trifluoro- and hexafluoro[3(3)](1,3,5)cyclophanes 3 and 4 were synthesized with TosMIC coupling as a key reaction. The pi-pi absorption bands show blue shifts as the number of fluorine atoms is increased. In the crystalline state, characteristic stacking with the fluorinated benzene rings facing each other is observed in both cases.

Synthesis, structure, and photoreactions of fluorinated 2,11‐diaza[32]paracyclophane: Photochemical formation of cage‐diene type benzene dimer

“…Therefore, the fluorine substitution modifies crystal structure of the azacyclophane system. Such effects of fluorine substitution on crystal structures have also been reported for [3 3 ]cyclophane system …”

“…Thus, it would be of interest to reveal the substituent effects on the photochemical behavior. It has been reported that introduction of fluorine atoms into aromatic cores of [3 3 ]cyclophanes significantly affected the electronic features of the carbon‐bridged cyclophane, thus, electronic absorption band of hexafluoro[3 3 ](1,3,5)cyclophane remarkably blue shifted compared to that of nonsubstituted parent cyclophane . Fluorination on the side chains may modify photochemical properties of a cyclophane system.…”

“…It has been reported that introduction of fluorine atoms into aromatic cores of [3 3 ]cyclophanes significantly affected the electronic features of the carbon-bridged cyclophane, thus, electronic absorption band of hexafluoro [3 3 ](1,3,5) cyclophane remarkably blue shifted compared to that of nonsubstituted parent cyclophane. [13] Fluorination on the side chains may modify photochemical properties of a cyclophane system. Upon photolysis, [2 2 ](1,4)anthracenoparacyclophane having fluorinated side chains underwent unusual intermolecular [π2s + π2s] dimerization.…”

Solid‐State Structural Study of the Charge‐Transfer Complexes of 5,7,9‐Trimethyl‐ and 2,11,20‐Trithia[33](1,3,5)cyclophanes

“…[3a] In the crystal packing diagram of the [3 n ]CPs, neighboring cyclophane molecules are arranged in an orthogonal fashion, [3] whereas the 5,7, 9-trifluoro-and 5,7,9,14,16,18-hexafluoro[3 3 ] (1,3,5)CPs are stacked with the fluorinated benzene rings facing each other, with the repeated stacking forming a column in the solid state. [4] We have modified the [3 3 ](1,3,5)CP skeleton in order to study the donor (D)Ϫacceptor (A) interaction in the solid state in more detail. We chose 5,7,9-trimethyl[3 3 ](1,3,5)CP 1 as a donor with two binding sites of different donating ability, as well as 2,11,20-trithia[3 3 ](1,3,5)CP 4 [5] and 1,3,10,12,19,21-hexathia[3 3 ](1,3,5)CP 5 [6] as donors with enhanced intermolecular interactions in the crystal packing.…”

UV/Vis Spectra of Cyclophanes

“…Koga et al[66] have investigated the electronic spectra of a series of fluoro[3 3 ] (1,3,5)cyclophanes(63)(64)(65) along with the parent 66 as a reference in chloroform.The p-p* absorption bands show blue shifts as the number of fluorine atoms is increased. Although in 63 the longest-wavelength band (k max = 313 nm, lg e = 2.53) suffers a slight red shift compared with that of 66 (k max = 308 nm, lg e = 1.94), the band shows a gradual blue shift as the number of fluorine atoms increases: 64 (k max = 296 nm, lg e = 1.93), 65 (k max = 291 nm, lg e = 2.27).…”