The smallest oligothiophene diradicals by asymmetric substitution of quinoidal cores

Abstract

The asymmetry of our PTI-n diradical pursuing a soft donor–donor energy difference was the structural design that we characterised by several spectroscopic and magnetic tools complemented with quantum chemical calculations.

Asymmetric and zwitterionic Blatter diradicals

“…While symmetric diradicals have proliferated in the recent literature, achieving conjugated asymmetric diradicals is less common, due to the very delicate balance between the donor–acceptor character, which annihilates the diradical character in favor of closed-shell zwitterions. 24 This adverse situation has been saved here by incorporating an oxygen acceptor and a nitrogen donor with narrow donor–acceptor orbital energy gradient; thus, pBP is a new asymmetric diradical with a combination of zwitterion and diradical features. In the analogous isomer, mBP , the amine N lone-pair electron, instead of acting as an electronic barrier or stopper, turned out to behave as a good conjugation transmitter.…”

Bridging the gap from single molecule properties to organic semiconductor materials

“…The Kondo effect, which is caused by unpaired electrons in radicals [34][35][36][37][38] and metal complexes, can be utilized to determine whether a molecule contains spins in single-molecule devices. 39,40 In addition, the Kondo effect can be finely tuned by the Zeeman effect, which causes the splitting of the energy levels of spin electrons when a magnetic field is applied to the molecule.…”

Sufficient driving force for quinoidal isoindigo-based diradicaloids with tunable diradical characters

“…18,22,23 Besides the symmetric systems, push–pull type asymmetric diradicaloids by end-capping different terminal substituents or other constitutions, also adjust the relative contributions of quinoidal, diradical, and zwitterionic structures to the electronic structures of the ground state. 24–27…”

“…18,22,23 Besides the symmetric systems, push-pull type asymmetric diradicaloids by end-capping different terminal substituents or other constitutions, also adjust the relative contributions of quinoidal, diradical, and zwitterionic structures to the electronic structures of the ground state. [24][25][26][27] Polycyclic aromatic hydrocarbons and organic p-conjugated donor-acceptor systems are important parts of diradicaloid systems. 5,13 Besides the quinoidalized structures and the elongation of the skeleton, the donor-acceptor approach facilitates smaller HLGs.…”