Efficient synthesis and characterization of dibenzo[a,m]rubicenes and tetrabenzo[a,f,r,m]rubicenes.

We report an efficient synthesis of dibenzo[a,m]rubicenes and tetrabenzo[a,f,r,m]rubicenes involving ICl-mediated benzannulation of 1,4-diphenyl-2,5-dialkynylbenzene 5 as the key step. Preliminary data on the photophysical properties of these new indeno-PAHs are reported.

Functionalized dibenzo[g,p]chrysenes: variable photophysical and electronic properties and liquid-crystal chemistry.

The photophysical and electronic properties of dibenzo[ g, p]chrysenes bearing electron-rich and -deficient substituents vary markedly with these substituents. The chemistry of the first liquid-crystalline dibenzo[ g, p]chrysene is also described.

Enhancement of high-harmonic generation by laser-induced cluster vibration.

Sharp periodic enhancement of high-harmonic generation synchronized to prepulse-induced cluster vibration is observed. Tenfold enhancement of high-harmonic-generation efficiency is achieved by optimal selection of the prepulse-pump delay. This strong correlation between high-harmonic generation and cluster vibration also provides a new tool for studying the vibrational dynamics of nanometer atomic clusters.