Neutral and ionic complexes of C60 with metal dibenzyldithlocarbamates.: Reversible dimerization of C60•- in ionic multicomponent complex [Cr1(C6H6)2•+]•(C60•-)•0.5[Pd(dbdtc)2]

New molecular complexes Of C-60 with metal(II) dibenzyldithiocarbamates, M(dbdtC)(2)C-.(60)0.5(.)(C6H5Cl), where M = Cu-II, Ni-II, Pd-II, and Pt-II (1-4) and an ionic multicomponent complex [Cr-I(C6H6)2(.+)](.)(C-60(.-))-0.5[Pd(dbdtc)(2)] (5) (Cr(C6H6)(2): 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(C6H6)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(C6H6)2*+ radical cations are arranged between the layers. Fullerene radical anions form pairs within the layer with an interfullerene (CC)-C-... contact of 3.092(2) angstrom, 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, C-60(.-) can dimerize. According to SQUID and EPR, single-bonded diamagnetic (C60(-))(2) climers 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 (C-60(-)) (2) dimers in 5, the dissociation temperature is the lowest among those for ionic complexes Of C-60 (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.