Crystal structure and raman spectra of molecular complex [{Cd(Et$_2$dtc)}$_2$ $\cdot$ DABCO] $\cdot$ C$_{60}$ $\cdot$ (DABCO)$_2$ at high pressure

The crystal structure of the molecular donor-acceptor complex [{Cd(Et$_2$dtc)}$_2$ $\cdot$ DABCO] $\cdot$ C$_{60}$ $\cdot$ (DABCO)$_2$ (where dtc is dithiocarbamate, DABCO is diazabicyclooctane) was studied by X-ray diffraction (XRD) at high pressure using the diamond anvil cell (DAC) technique. The pressure dependence of lattice parameters is smooth and monotonous, the bulk modulus and its derivative $B_0$ = 7.94 GPa and $B'$ = 9.65 are close to those of pristine C$_{60}$. Raman spectra of the complex measured at $\lambda_{exc}$ = 532 nm showed a peculiarity in the pressure dependence of A$_g$(1), A$_g$(2), H$_g$(1) and H$_g$(7) modes of the C$_{60}$ molecule near 2 GPa. This peculiarity relates to pressure-assisted photopolymerization in the fullerene layers which is suppressed in Raman measurements at $\lambda_{exc}$ = 785 nm showing smooth pressure behavior of phonon modes.