5,10-Dimesityldiindeno[1,2-a:2′,1′-i]phenanthrene: a stable biradicaloid derived from Chichibabin's hydrocarbon

Abstract

A diindenophenanthrene biradicaloid, formally derived from Chichibabin's hydrocarbon, is obtained in a short, scalable synthesis.

The Low Lying Double-Exciton State of Conjugated Diradicals: Assessment of TDUDFT and Spin-Flip TDDFT Predictions

“…Conjugated diradical systems have attracted considerable interest in recent years owing to their potential electronic applications [1] in organic field effect transistors (OFETs) [2][3][4], organic photodetectors (OPDs) [5], and near-infrared (NIR) dyes [6,7], among others. Significant efforts have been devoted to stabilize the active open-shell molecules, and a large number of stable diradicals with an open-shell singlet ground state have been synthetized with different conjugated cores and varying diradical character [8][9][10][11][12]. There has been a tremendous effort also on the rationalization of the properties from a theoretical point of view, including their linear and non-linear optical properties and their application in singlet fission processes [13], etc.…”

“…Here, we extend the study and consider the four recently synthesized conjugated diradicals displaying a singlet ground state shown in the top part of Figure 1: Nonazethrene (NZ) [9], superoctazethrene (SOZ) [10], diindenophenanthrene derivative (DIPh) [12], and peri-tetracene (PT) [11]. This set is added to the previous set of molecules for the investigation of the double-exciton state.…”

Learning how to fine‐tune diradical properties by structure refinement

“…While we were one of the first research groups to do so, diindeno-fusion on either side of a pro-aromatic core (in our case a naphthalene and anthracene) has become a popular strategy towards producing diradical PCHs that are robust enough to be isolated and further studied (Figure 8). In the last 3 years, there have been reports of diindenopicenes (23), [42] fluoreno[2,3-b]fluorene ("diindenonaphthalene," 24), [18b] diindenophenanthrene (DIPh, 25), [43] diindenocorannulenes (DIC, 26 and 27), [44] and diindenobischrysene (28), [45] all of which possess diradical character once the central π-system has been capped with two indeno units. Interestingly enough, recently reported DIPh 25 is actually a constitutional isomer of DIAn 9, where the fusion pattern of the three F I G U R E 7 Bleaney-Bowers fits of the superconducting quantum interference device (SQUID) data for the series of molecules based on anthracene (9, 18-21) and naphthalene (13,14,22) pro-aromatic cores, illustrating our ability to tune ΔE ST values by discrete structural modification central benzenes is the main structural difference between the two compounds.…”

The Low Lying Double-Exciton State of Conjugated Diradicals: Assessment of TDUDFT and Spin-Flip TDDFT Predictions

“…Conjugated diradical systems have attracted considerable interest in recent years owing to their potential electronic applications [1] in OFETs [2][3][4], OPDs [5] and near-infrared (NIR) dyes [6,7], among others. Significant efforts have been devoted to stabilize the active open-shell molecules, and a large number of stable diradicals with an open-shell singlet ground state have been synthetized with different conjugated cores and varying diradical character [8][9][10][11][12]. There has been a tremendous effort also on the rationalization of the properties from a theoretical point of view, including their linear and non-linear optical properties and their application in singlet fission processes [13] etc.…”

“…Here we extend the study and consider the four recently synthesized conjugated diradicals displaying a singlet ground state shown in the top part of Fig. 1: nonazethrene (NZ) [9], superoctazethrene (SOZ) [10], diindenophenanthrene derivative (DIPh) [12] and peri-tetracene (PT) [11]. This set is added to the previous set of molecules for the investigation of the double-exciton state.…”