Influence of π-Stacking on the Resonant Enhancement of the Second-Order Nonlinear Optical Response of Dipolar Chromophores

Abstract

The wavelength-dependent second-harmonic generation (SHG) efficiency of two simple dipolar chromophores, 4-NO2C6H4N(H)Bun (1) and 4-NO2C6H4SN(H)But (2), was compared in solution and in the solid state. Hyper-Rayleigh scattering measurements at 532 nm provided comparable molecular first hyperpolarizabilities. Both compounds crystallize in non-centrosymmetric space groups, but a more efficient arrangement of dipole moments results in a significantly larger deff value for 2. Kurtz-Perry experiments from 450 to 700 nm revealed an important difference in the resonant component of the nonlinear optical responses of these compounds; the SHG efficiency of crystalline 1 depends more strongly on the incident wavelength than that of 2. This would be in contradiction with the TD-DFT excitation energies calculated for these molecules, but the observation can be explained by the resonant contribution from low-energy interchromophore excitations enabled by pi-stacking in the crystal of 1.

A Prototype for Graphene Material Simulation: Structures and Interaction Potentials of Coronene Dimers

“…Aromatic−aromatic interactions play key roles in molecular recognition, − protein folding, ,− stacked nucleobases, − drug − and pesticide intercalation, nonlinear optical materials, − crystal packing, − self-assembly, − soot, − solvation, − partitioning of organic pollutants in the environment, − supramolecular chemistry, − catalysis, and soft materials.…”

“…Aromatic-aromatic interactions play key roles in molecular recognition, [1][2][3][4] protein folding, 2,5-9 stacked nucleobases, [10][11][12] drug [13][14][15][16] and pesticide 17 intercalation, nonlinear optical materials, [18][19][20] crystal packing, [21][22][23] self-assembly, [24][25][26][27][28] soot, [29][30][31][32][33] solvation, [34][35][36] partitioningoforganicpollutantsintheenvironment, [37][38][39][40][41][42][43] supramolecular chemistry, [44][45][46][47][48] catalysis, 49 and soft materials.…”

Isoxazolone-based single crystals with large second harmonic generation effect

“…As is well known, π-π interactions result in mutual polarizations of molecules, so the hyperpolarizability of the DLS and MLS molecules in the crystal phase can be strongly enhanced. 35,36 Taking the dispersion in the crystal phase into consideration, 34 DLS and MLS have quite lower first excited energies (2.91 eV and 1.93 eV, respectively) compared with OH1 (3.14 eV), which show that the dispersion in DLS and MLS crystals is more serious than in OH1 crystal. Consequently, with increasing wavelength, the increasing magnitude of the SHG coefficients is larger for DLS and MLS.…”

Diisopropylammonium 2-[(2,4-dinitrophenyl)sulfanylaminocarbonyl]benzoate

“…The benzene rings are slightly distorted and the nitro groups are slightly twisted with respect to the ring to which they are bonded ( Table 1). The CÐS and NÐS bond distances [1.760 (2) and 1.6885 (18) A Ê , respectively] are normal for this type of compound [literature values are in the ranges CÐS = 1.763±1.791 A Ê and SÐN = 1.679±1.695 A Ê (Mahmoudkhani & Vargas-Baca, 2003;Glidewell et al, 2003;Lee et al, 1995;Zhang et al, 2005;Bao et al, 2003)]. The SÐN distance is shorter than the normal SÐN single-bond length (1.74 A Ê ; Pauling, 1960), but is normal for this type of structure as a result of the % character of the SÐN bond.…”