The Design of Radical Stacks: Nitronyl-Nitroxide-Substituted Heteropentacenes

The Design of Radical Stacks: Nitronyl-Nitroxide-Substituted Heteropentacenes Full article

Journal

ChemistryOpen
ISSN: 2191-1363

Output data

Year: 2017, Volume: 6, Number: 5, Pages: 642-652 Pages count : 11 DOI: 10.1002/open.201700110

Tags

density functional and ab into calculations; EPR spectroscopy; fused thiophene; nitronyl nitroxides; pi-stacking

Authors

Tretyakov Evgeny ^1,2 , Keerthi Ashok ³ , Baumgarten Martin ³ , Veber Sergey ^2,4 , Fedin Matvey ^2,4 , Gorbunov Dmitry ^2,5 , Shundrina Inna ¹ , Gritsan Nina ^2,5

Affiliations

1	(Данные Web of science) NN Vorozhtsov Inst Organ Chem, 9 Ac Lavrentiev Ave, Novosibirsk 630090, Russia
2	(Данные Web of science) Novosibirsk State Univ, 2 Pirogova Str, Novosibirsk 630090, Russia
3	(Данные Web of science) Max Planck Inst Polymer Res, Ackermannweg 10, D-55128 Mainz, Germany
4	(Данные Web of science) Int Tomog Ctr, 3a Inst Skaya Str, Novosibirsk 630090, Russia
5	(Данные Web of science) VV Voevodsky Inst Chem Kinet & Combust, 3 Inst Skaya Str, Novosibirsk 630090, Russia

The first alkyl chain-anchored heteropentacene, dithieno[2,3-d;2',3'-d]benzo-[1,2-b;3,4-b]dithiophene (DTmBDT), mono- or disubstituted with a nitronyl nitroxide group has been prepared through a cross-coupling synthetic procedure of the corresponding dibromo-derivative (Br-2-DTmBDT) with a nitronyl nitroxide-2-ide gold(I) complex. The synthesized nitroxides possess high kinetic stability, which allowed us to investigate their structure and thermal, optical, electrochemical, and magnetic properties. Single-crystal X-ray diffraction of both mono- and diradicals revealed that the nitronyl nitroxide group lies almost in the same plane as the nearest side thiophene ring. Such arrangement favors formation of edge-to-edge dimers, which then form close pi-stacks surrounded by interdigitating alkyl chains. Before melting, these nitranyl nitroxide radical substituted molecules undergo at least two different phase transitions (PTs): for the monoradical, PTs are reversible, accompanied by hysteresis, and occur near 13 and 83 degrees C; the diradical upon heating shows a reversible PT with hysteresis in the temperature range 2-11 degrees C and an irreversible PT near 135 degrees C. PTs of this type are absent in Br-2-DTmBDT. Therefore, the step-by-step substitution of bromine atoms by nitronyl nitroxide groups changes the structural organization of DTmBDT and induces the emergence of PTs. This knowledge may facilitate crystal engineering of pi-stacked paramagnets and related molecular spin devices.

Tretyakov E. , Keerthi A. , Baumgarten M. , Veber S. , Fedin M. , Gorbunov D. , Shundrina I. , Gritsan N.
The Design of Radical Stacks: Nitronyl-Nitroxide-Substituted Heteropentacenes

ChemistryOpen. 2017. V.6. N5. P.642-652. DOI: 10.1002/open.201700110 WOS Scopus РИНЦ

Full text from publisher

Published online:	Aug 30, 2017
Published print:	Oct 1, 2017

Web of science	WOS:000413038400006
Scopus	2-s2.0-85028860292
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