Functionalized Carbon Nanohoops: Synthesis and Structure of a [9]Cycloparaphenylene Bearing Three 5,8-Dimethoxynaphth-1,4-diyl Units

Abstract

A functionalized [9]cycloparaphenylene ([9]CPP) bearing three evenly spaced 5,8-dimethoxynaphth-1,4-diyl units and two macrocyclic [6]CPP precursors have been synthesized. The Diels-Alder reaction between (E,E)-1,4-bis(4-bromophenyl)-1,3-butadiene and 1,4-benzoquinone followed by methylation produces cis-5,8-bis(4-bromophenyl)-5,8-dihydro-1,4-dimethoxynaphthalene as the key intermediate for the construction of the hooplike structures. The nickel-mediated homocoupling reactions followed by aromatization led to the functionalized [9]CPP.

Design and Synthesis of Carbon Nanotube Segments

“…[57] The cis-configurated L-shaped Homocoupling reaction of 121 afforded macrocycle 122,a nd carbon nanoring 123 was obtained by oxidative aromatization of the cyclohexadiene moiety by using 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ). Thed imethoxynaphthalene-containing carbon nanoring 123 represents a( 9,9)CNT segment.…”

Nano-rings with a handle – Synthesis of substituted cycloparaphenylenes

“…The group of Wang [56] explored a different strategy to integrate a substituted naphthylene unit into CPP (Scheme 8). The square shaped subtituent was synthesized via Diels–Alder reaction of 35 and 31 selectively affording the cis product 36 after methylation.…”

Belt‐Shaped Cyclonaphthylenes

“…Although the belt-shaped structures of u- [8]CaNAP were revealed in the crystalline state,t hey were not persistent in solution because of rapid rotation of the naphthylene units. [15,16] We thus incorporated four -CH 2 CH 2 -(hereafter denoted methylene) bridges into the nanohoop to afford b- [8]CaNAP and successfully rigidify the belt shape in solution. TheU V/Vis absorption maxima of [n]CPPs are known to be insensitive to the number of p electrons in the conjugated system.…”