Vibrational spectra of cubane and four of its deuterated derivatives

Abstract

Vibrational spectra are reported for cubane, cubane-t/i, .rym-cubane-ti/2, Ym-cubane-í/6, and cubane-t/g-Infrared spectra are from 400 to 3600 cm-1 for CS2 and CCI4 solutions, and for a solid deposited from the vapor at ~100 K. Raman spectra are for the same solutions and for the polycrystalline solid at room temperature. Vibrational assignments have been made for all the fundamentals of all five compounds, 120 modes in all. The fortuitous crystal structure of cubane and cubane-/g was an important aid. Of the 18 fundamentals of cubane, only one or two are not certain. The spectra show almost no effect of the severe bond angle strain. Also there are no low molecular modes; the lowest for cubane is 617 cm'1.

Pressure‐dependent infrared spectroscopy on the fullerene rotor–stator compound C60–C8H8

“…The infrared spectrum of C 60 -C 8 H 8 consists of seven vibrational modes, three of C 8 H 8 [4] and four of C 60 [5], all of T 1u symmetry, in accordance with the high-symmetry point groups of the two species (O h for cubane and I h for C 60 ). Changes in the infrared spectrum upon symmetry lowering have been studied extensively, for cubane derivatives with several sidegroups [4] and for fullerene solids below the orientational ordering temperature [6] and in various polymers [7].…”

Infrared spectroscopy on the rotor–stator compounds C60–C8H8 and C70–C8H8 under pressure

“…Since only weak van der Waals interaction between the molecules is present, the characteristic vibrational modes of the fullerene molecules can be observed in the infrared spectra of C 60 -C 8 H 8 and C 70 -C 8 H 8 without any frequency shift compared to pure C 60 and C 70 , together with the three characteristic modes of cubane [5][6][7][8]. A few selected vibrational modes in the infrared absorbance spectra of C 60 -C 8 H 8 and C 70 -C 8 H 8 for different pressures are shown in Fig.…”

Vibrational Spectra of C60·C8H8 and C70·C8H8 in the Rotor-stator and Polymer Phases

“…We could observe all of these modes in the spectrum of C 60 ·C 8 H 8 (the H g (1) mode can be seen in Fig. 2 7 shows a more complicated spectrum because of the lower site symmetry. The eight Raman-active modes of cubane are classified as 2 A 1g + 2 E g + 4 T 2g .…”

“…7 If we compare the vibrational frequencies for various environments of the cubane molecule, a clear trend can be observed. The highest vibrational frequencies occur in the gas phase.…”

“…Tables 1 and 2, and those of C 70 ·C 8 H 8 in Tables 3 and 4. We compare these frequencies to experimental data on cubane 7 and C 60 (Ref. 8) and calculated Raman 9 and infrared 10 spectra of C 70 , respectively.…”