C20 Carbon Clusters: Fullerene–Boat–Sheet Generation, Mass Selection, Photoelectron Characterization

摘要: Electron-impact ionization in a time-of-flight mass spectrometer of C20H0–3Br14–12 probes—secured from C20H20 dodecahedrane by “brute-force” bromination protocol—provided bromine-free C20H0–2(3) anions amounts that allowed the clean mass-separation hydrogen-free C20− ions and photoelectron (PE) spectroscopic characterization as C20 fullerene (electron affinity (EA)=2.25±0.03 eV, vibrational progressions 730±70). The extremely strained surfaced kinetically rather stable entities (lifetime at least total flight time 0.4 ms); they only very sluggishly expel C2 unit. HOMO LUMO are suggested to be almost degenerate (ΔE=0.27 eV). assignment was corroborated PE bowl (EA=2.17±0.03 progression 2060±50 cm−1) analogously generated C20H10 corannulene (C20H1–3Br9–8 samples) comparably stable. Highly resolved low-temperature spectra known ring (EA=2.49±0.03 2022±45 455±30 cm−1), obtained graphite, display an admixture of, most probably, bicyclic isomer (EA=3.40±0.03 cm−1). C20+(−) C20H2+(−) cluster polybrominated perylene (C20H0–2Br12–10) have (most probably) retained planar perylene-type skeleton (sheet, EA=2.47±0.03 2089±30 492±30 cm−1 EA=2.18±0.03 2105±30 468±30