71391-53-2Relevant articles and documents
Neutral and ionic complexes of C60 with metal dibenzyldithiocarbamates. Reversible dimerization of C60 ?- in ionic multicomponent complex [Crl(C 6H6)2?+]·(C 60?-)·0.5[Pd(dbdtc)2]
Konarev, Dmitri V.,Kovalevsky, Andrey Yu.,Otsuka, Akihiro,Saito, Gunzi,Lyubovskaya, Rimma N.
, p. 9547 - 9553 (2008/10/09)
New molecular complexes of C60 with metal(II) dibenzyldithiocarbamates, M(dbdtc)2·C60·0. 5(C6H5Cl), where M = CuII, NiII, PdII, and PtII (1-4) and an ionic multicomponent complex [Crl(C6H6)2?+] ·(C60?-)·0.5[Pd(dbdtc)2] (5) (Cr-(C6H6)S: bis(benzene)chromium) were obtained. According to IR, UV-visible-NIR, and EPR spectra, 1-4 involve neutral components, whereas 5 comprises neutral Pd(dbdtc)2 and C 60?- and Crl(C6H 6)2?+ radical ions. The crystal structure of 5 at 90 K reveals strongly puckered fullerene layers alternating with those composed of Pd(dbdtc)2. The Crl(C6H 6)2?+ radical cations are arranged between the layers. Fullerene radical anions form pairs within the layer with an interfullerene C...C contact of 3.092(2) A, indicating their monomeric state at 90 K. This contact is essentially shorter than the sum of van der Waals radii of two carbon atoms, and consequently, C60 ?- can dimerize. According to SQUID and EPR, single-bonded diamagnetic (C60-)2 dimers form in 5 below 150-130 K on slow cooling and dissociate above 150-170 K on heating. The hysteresis was estimated to be 20 K. For the (C60-) 2 dimers in 5, the dissociation temperature is the lowest among those for ionic complexes of C60 (160-250 K). Fast cooling of the crystals within 10 min from room temperature down to 100 K shifts dimerization temperatures to lower than 60 K. This shift is responsible for the retention of a monomeric phase of 5 at 90 K in the X-ray diffraction experiment.
