ISSN 1070-3632, Russian Journal of General Chemistry, 2019, Vol. 89, No. 5, pp. 971–987. © Pleiades Publishing, Ltd., 2019. Russian Text © The Authors(s), 2019, published in Zhurnal Obshchei Khimii, 2019, Vol. 89, No. 5, pp. 786–804. 971 Electroconducting Radical-Cation Salts Based on Tetrathiafulvalene Derivatives and Transition Metals Bis(dicarbollides) V. I. Bregadze a , O. A. Dyachenko b , O. N. Kazheva b , I. D. Kosenko a , A. V. Kravchenko c , I. B. Sivaev a *, and V. A. Starodub d a A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, ul. Vavilova 28, Moscow, 119991 Russia *e-mail: sivaev@ineos.ac.ru b Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka, Russia c V.N. Karazin Kharkiv National University, Kharkov, Ukraine d Jan Kochanowski University, Kielce, Poland Received November 22, 2018; revised November 22, 2018; accepted November 29, 2018 Abstract—The radical-cationic salts based on tetrathiafulvalene derivatives and bis(dicarbollide) transition metal complexes [3,3'-M(1,2-C 2 B 9 H 11 ) 2 ] – (M = Co, Ni, Fe, Cr) are promising for the creation of new molecular conductive materials due to the almost unlimited possibilities of their modification. The relationships between the properties of both components of the cation-radical salts, their crystal structure, and electrical and magnetic properties have been analyzed on the basis of the literature and our own data. The effect of various substituents in metallacarborane anions on the structure and physical properties of their radical cation salts based on tetrathiafulvalene and its derivatives has been revealed. Data on the structure and properties of the radical cation salts with other borate anions are presented for comparison. Keywords: tetrathiafulvalene, bis(dicarbollide) transition metal complexes, radical-cation salts, structure– property relationship Due to wide range of electrical properties varied from dielectric (isolators) to superconductors and the ability to form magnetic-ordered structures, radical cation salts based on tetrathiafulvalene and their derivatives have been widely used in the development of molecular electroconductive and magnetic materials [1–6]. The most characteristic feature of such materials is the presence of two sublattices, one of which is set up by successive π-electron donor layers based on tetrathiafulvalene derivatives responsible for electron conduction, while the other one consists of anion layers, compensating cation radical charge. Introduction of transition metals possessing magnetic moment into these anions, can lead to their exchange interaction with π-electrons of cations radical, which can be used for the creation of magnetic-ordered electroconductive organic materials [7, 8]. Conducting properties of these materials are due to the presence of π-electrons of donors—cation radical derivatives of tetrathiafulvalene packed in compact stacks and layers. Generally, anions are not directly involved in the conductivity mechanism, yet their structure-directing action is of primary importance in the formation of conductive properties of molecular conductors, since complementarity of cation radical and anion sublattices is a decisive factor determining the diversity of the types of conducting layers. X-ray diffraction studies of molecular conductors have demonstrated the set of structural features of cation radical layer package such as conformational and charge ordering in cation radical layers as well as commensurate and incommensurate structure modulations corresponding to the component position ordering of the anion sublattice. Hence, fine tuning of DOI: 10.1134/S1070363219050177