Salavat S. Khasanov

Dimerization of C60˙− in multi-component ionic complexes with bis(ethylenedithio)tetrathiafulvalene: (cation+)2·ET·(C60˙−)2

Two multi-component ionic complexes (cation+)2·ET·(C60˙−)2 comprising C60˙− radical anions, neutral bis(ethylenedithio)tetrathiafulvalene (ET) molecules and N-methyldiazabicyclooctane (1) or N,N-dimethylpyrrolidine (2) cations were obtained. At room temperature 1 involves monomeric nearly freely rotating C60˙− radical anions arranged in zigzag double chains passing along the a axis and separated by ET molecules and cations. Dimerization is observed in 1 at 280–250 K within C60˙− pairs with 9.922 A center-to-center interfullerene distances. It was shown that dimerization temperatures are dependent on the initial distance between the C60˙− anions in the monomeric phase, and the shortest center-to-center interfullerene distance in 1 provides the highest dimerization temperature among ionic C60 complexes studied so far. The crystal structure of the dimeric phase was determined at 100 K. The (C60−)2 dimers are bound by one single bond of 1.589(2) A length with an interfullerene center-to-center distance of 9.288 A. The room temperature unit cell parameters of 2 are similar to those of 1 and dimerization is realized in this complex at 280–250 K. Dimerization is reversible in both complexes and results in the transition of the complexes from a paramagnetic to a diamagnetic state.

Structural aspects of two-stage dimerization in an ionic C60 complex with bis(benzene)chromium: Cr(C6H6)2·C60·C6H4Cl2

Single crystals of the ionic C60 complex with bis(benzene)chromium: {Cr(I)(C6H6)2(.+)}.(C60.-)).C6H4Cl2 (1) were obtained. The crystal structure of 1 shows the presence of monomeric C60.- radical anions at 250 K and the formation of single-bonded (C60-)2 dimers at 90 K. The dimerization is realized in two types of the C60.-) pairs with different interfullerene center-to-center distances of 10.052 and 10.279 A arranged in zigzag chains along the a-direction. As a result, two symmetrically independent (C60-)2 dimers found in 1 at 90 K have different environments, intercage C-C bond lengths and C60- center-to-center distances. Such differences should provide different thermal stability of these dimers and result in the appearance of two stages at the dimerization. Indeed, according to SQUID measurements, the magnetic moment of 1 decreases stepwise at the dimerization in two temperature ranges at 240-200 and 200-160 K.

The formation of single-bonded (C60-)2 and (C70-)2 dimers in ionic complexes of fullerenes

New ionic complexes of fullerenes C 60 and C 70 : Cp* 2 CrC 60 (C 6 H 4 Cl 2 ) 2 (1) and Cs 2 (C 70 ) 2 CTV(DMF) 7 (C 6 H 6 ) 0.75 (2) (Cp* 2 Cr: decamethylchromocene; CTV: cyclotriveratrylene) have been obtained as single crystals. It is shown that paramagnetic fullerene radical anions form diamagnetic single-bonded (C 60 ) 2 and (C 70 -) 2 dimers in both complexes at low temperatures, the molecular structures of which are presented. The dimer-monomer phase transitions at 200-220 K in l (reversible) and at 360-390 K in 2 are discussed.

First ionic multi-component complex of fullerene C60(CN)2 with Co(II)tetraphenylporphyrin and bis(benzene)chromium ☆

First ionic multi-component complex CoTPP.2C 60 (CN) 2 .2Bz 2 , Cr.3C 6 H 4 Cl 2 (CoTPP: cobalt(II)tetraphenylporphyrin Bz 2 Cr: bis(benzene)chromium; C 6 H 4 Cl 2 : o-dichlorobenzene) has been synthesized. CoTPP molecules and fullerides form channels providing the accommodation of Bz 2 Cr .+ and C 6 H 4 Cl 2 . For the first time it is shown that, in contrast to the neutral fullerenes, the cobalt atom of CoTPP coordinates to the fullerene anions with short Co...C(fullerene) distance of 2.28 A. CoTPP-C 60 (CN) 2 -anion is diamagnetic according to the EPR- and SQUID-measurements. The shape of the starting molecule retains at the formation of the C 60 (CN) 2 .-anion-radicals. The length of C≡N bonds are 1.143 and 1.161 A.

CCDC 1465068: Experimental Crystal Structure Determination

Related Article: Dmitri V. Konarev, Alexey V. Kuzmin, Yoshiaki Nakano, Salavat S. Khasanov, Manabu Ishikawa, Akihiro Otsuka, Hideki Yamochi, Gunzi Saito, Rimma N. Lyubovskaya|2016|Dalton Trans.|45|10780|doi:10.1039/C6DT01132B

CCDC 889078: Experimental Crystal Structure Determination

Related Article: Dmitri V. Konarev, Leokadiya V. Zorina, Salavat S. Khasanov and Rimma N. Lyubovskaya|2013|Eur.J.Inorg.Chem.||309|doi:10.1002/ejic.201200822

Ionic Multi-Component Complexes of Fullerenes: Structures and Magnetic Properties

Abstract New ionic multi‐component complexes (TBPDA)2·(C60 •−)·(D+), where TBPDA is N,N,N′,N′‐tetrabenzyl‐p‐phenylenediamine and D is decamethylchromocene (Cp*2Cr, 1), decamethylcobaltocene (Cp*2Co, 2), and tetrakis(dimethylamino)ethylene (TDAE, 3). The presence of D+, C60 •− and neutral TBPDA in 1–3 was proved by the IR and UV‐visible‐NIR spectra. D+ and C60 •− form loose layers in 1 and 3 and are spatially separated by bulky TBPDA molecules. The EPR spectra of the complexes show single Lorentzian line with g=2.2526 and ΔH=215 mT (1), g=1.9999 and ΔH=6.7 mT (2), and g=2.0009 and ΔH of 2.93 mT (3) at RT. The EPR signal of 2 was attributed to C60 •− (Cp*2Co+ is diamagnetic), whereas those in 1 and 3 to resonating signal between C60 •− (g=1.9996–2.0000) and cations Cp*2Cr+ (1) or TDAE•+ (3) due to indirect coupling. The EPR signals from 2 and 3 are split into two components below 50 and 60 K and the magnetic moments of 1–3 decrease below 50–100 K. Both effects are associated with the formation of field‐induced short‐range antiferromagnetically ordered clusters. It was shown that D+ cations do not noticeably affect the antiferromagnetic interaction of spins in 1–3 probably due to their isolation by benzyl groups of TBPDA.