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Second Harmonic Generation Signatures of Supramolecular Assemblies Based on Amide Moieties
Tárcius N Ramos1, Laura Le Bras2, Yves L Dory3
1Laboratory of Theoretical Chemistry, Namur Institute of Structured Matter (NISM), University of Namur, rue de Bruxelles, 61, 5000, Namur, Belgium.
Summary
Benzene-1,3,5-tricarboxamide assemblies show size-dependent second harmonic generation (SHG) responses. Iodine atoms enhance intrinsic SHG, while side chains influence orientation, impacting bioimaging potential.
Area of Science:
- Nonlinear optics
- Materials science
- Computational chemistry
Background:
- Second harmonic generation (SHG) is a valuable nonlinear optical phenomenon for bioimaging.
- Understanding aggregate formation and its impact on SHG responses is crucial for developing advanced imaging techniques.
- Benzene-1,3,5-tricarboxamide derivatives are promising candidates for supramolecular assemblies with tunable optical properties.
Purpose of the Study:
- To evaluate the SHG first hyperpolarizabilities () of benzene-1,3,5-tricarboxamide assemblies.
- To investigate the influence of aggregate size, iodine substitution, and side chain modifications on SHG responses.
- To explore the potential of these derivatives as functional materials for bioimaging applications.
Main Methods:
- Density functional theory (DFT) calculations were employed to determine SHG properties.
- A sequential molecular dynamics (MD) then quantum mechanics (QM) approach was used to incorporate dynamic structural effects.
- Hyper-Rayleigh Scattering (HRS) and Electric-Field-Induced Second Harmonic Generation (EFISHG) were considered.
Main Results:
- Aggregate size significantly influences total SHG responses, with up to an 18-fold increase observed for a pentamer compared to a monomer.
- Intrinsic SHG responses (HRS) are enhanced by the presence of iodine atoms on the phenyl core.
- Side chains modulate the relative orientation of dipole moment and hyperpolarizability vectors, affecting EFISHG quantities.
- The radial component of is dominant in compounds exhibiting the largest responses.
Conclusions:
- Benzene-1,3,5-tricarboxamide assemblies possess tunable SHG properties dependent on their size and chemical modifications.
- Iodine substitution and side chain engineering are effective strategies to enhance and control SHG responses for bioimaging.
- The computational approach provides valuable insights into structure-property relationships for designing novel nonlinear optical materials.
Keywords:
aggregationfirst hyperpolarizabilitymolecular modelingnonlinear opticssecond harmonic generationMore Related Videos
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