title: Nonlinear optical absorption properties of two multisubstituted p-dimethylaminophenylethenyl pyridiniums.
abstract: Two multisubstituted D-pi-A type pyridinium salts, N-methyl-2,6-di[(E)-p-dimethylaminophenylethenyl]pyridinium iodide (1) and N-methyl-2,4,6-tri[(E)-p-dimethylaminophenylethenyl]pyridinium iodide (2), were synthesized with good yields by a modified method, and the structure of 1 was confirmed by X-ray diffraction. The nonlinear optical absorption (NOA) properties of the two compounds in the solution state were investigated by the Z-scan technique. Compounds 1 and 2 both exhibited very strong saturated absorption at picosecond pulse, and 1 displayed reverse saturated absorption, while 2 revealed saturated absorption properties at the nanosecond pulse. The electron-donating ability, number of side chains, and molecular coplanar characteristics of the compounds have a significant impact on their NOA properties.
authors.affiliation: Department of Chemistry, East China Normal University, Shanghai 200062, People's Republic of China.
authors.forename: Xiuling
authors.initials: X
authors.lastname: Xu
authors.forename: Wenwei
authors.initials: W
authors.lastname: Qiu
authors.forename: Qing
authors.initials: Q
authors.lastname: Zhou
authors.forename: Jie
authors.initials: J
authors.lastname: Tang
authors.forename: Fan
authors.initials: F
authors.lastname: Yang
authors.forename: Zhenrong
authors.initials: Z
authors.lastname: Sun
authors.forename: Pierre
authors.initials: P
authors.lastname: Audebert