Impact of the dicyanomethylene substitution position on the cyclophane macrocycle formation in carbazole-based biradicals

Badía-Domínguez, María Irene; Sakamaki, Daisuke; Seki, Shu; Hartl, Frantisek; López-Navarrete, Juan Teodomiro; Hernández-Jolín, Víctor; Ruiz-Delgado, María del Carmen; Hongxiang, Li

Abstract

π-Conjugated biradical compounds, featuring unique unsaturated valences and radical centers in the ground state, are fundamentally important for understanding the nature of chemical bonds and have potential applications in material science. [1] Recently, it has been demonstrated that several -conjugated mono- and biradicals systems form long strain -bonds between two unpaired electrons resulting in macrocyclic or staircase oligomers or polymers by self-assembly processes. [2] Therefore, these materials are potential building blocks for dynamic covalent chemistry (DCC) since the aggregates can be formed or broken upon soft external stimuli. For instance, 2,7-dicyanomethylene-9-(2-ethylhexyl)carbazole biradical (p-Cz-alkyl in Figure 1) reversibly converts upon soft stimuli (temperature, pressure, light) to a cyclophane tetramer as a result from the formation (or bond cleavage) of long C-C single bonds.[3] Here, we present an experimental and theoretical study in order to investigate how the N-substitution and the change from para- to meta-dicyanomethylene substitution on carbazole-based biradicals affects their biradical character and thus, their tendency to act as useful motifs for DCC (see Figure 1).

Impact of the dicyanomethylene substitution position on the cyclophane macrocycle formation in carbazole-based biradicals

Author: Badía-Domínguez, María Irene,Sakamaki, Daisuke,Seki, Shu,Hartl, Frantisek,López-Navarrete, Juan Teodomiro,Hernández-Jolín, Víctor,Ruiz-Delgado, María del Carmen,Hongxiang, Li

Year: 2019

Source: https://riuma.uma.es/xmlui/bitstream/10630/17143/1/Abstrac_Irene.pdf

Symposium on Compu ing
π
-Conjuga ed Compounds (C
π
C-10), Valencia, 1-2. 02.19
Impac o he Dicyanome hylene Subs i u ion Posi ion on he
Cyclophane Mac ocycle Fo ma ion in Ca bazole-based Bi adicals
I. Badía-Domínguez1, Juan T. López Na a e e1, V. He nández Jolín1, D. Sakamaki2, S. Seki2, F. Ha l3, H.
Li4, M. Ca men Ruiz Delgado1
1 Depa men o Physical Chemis y, Uni e si y o Malaga, Campus de Tea inos s/n, 229071, Malaga,
Spain.
2 Depa men o Molecula Enginee ing G adua e School o Enginee ing, Kyo o Uni e si y, Nishikyo-ku,
Kyo o 615-8510, Japan.
3 Depa men o Chemis y, Uni e si y o Reading, Whi eknigh s, Reading RG6 6AD,
Uni ed Kingdom.
4 Shanghai Ins i u e o O ganic Chemis y, Chinese Academy o Sciences, No.345 Lingling Rd., Shanghai,
200032, China.
E-mail : [email p o ec ed]
π-Conjuga ed bi adical compounds, ea u ing unique unsa u a ed alences and adical cen e s
in he g ound s a e, a e undamen ally impo an o unde s anding he na u e o chemical
bonds and ha e po en ial applica ions in ma e ial science. [1] Recen ly, i has been
demons a ed ha se e al π-conjuga ed mono- and bi adicals sys ems o m long s ain σ-
bonds be ween wo unpai ed elec ons esul ing in mac ocyclic o s ai case oligome s o
polyme s by sel -assembly p ocesses. [2] The e o e, hese ma e ials a e po en ial building
blocks o dynamic co alen chemis y (DCC) since he agg ega es can be o med o b oken
upon so ex e nal s imuli. Fo ins ance, 2,7-dicyanome hylene-9-(2-e hylhexyl)ca bazole
bi adical (p-Cz-alkyl in Figu e 1) e e sibly con e s upon so s imuli ( empe a u e, p essu e,
ligh ) o a cyclophane e ame as a esul om he o ma ion (o bond clea age) o long C-C
single bonds.[3] He e, we p esen an expe imen al and heo e ical s udy in o de o in es iga e
how he N-subs i u ion and he change om pa a- o me a-dicyanome hylene subs i u ion on
ca bazole-based bi adicals a ec s hei bi adical cha ac e and hus, hei endency o ac as
use ul mo i s o DCC (see Figu e 1).
Figu e 1. Ca bazole-based bi adical sys ems unde s udy.
Re e ences
[1] M. Abe, Chem. Re . 2013, 113, 7011 – 7088.
[2] O. Kohei, H. Sho a, I. Yuki, S. Daisuke, S. Shu, Ang. Chem. In . Ed. 2017, 56, 16597-16601.
[3] D. Wang, C. C. Fe ón, J. Li, S. G. Valenzuela, R. P. O iz, J. T. L. Na a e e, V. H. Jolin, X.
Yang, M. P. Ál a ez, V. G. Baonza, F. Ha l, M. C. R. Delgado, H. Li, Chem. Eu . J. 2017, 23, 13776
– 13783.