Photophysical studies of some heterocyclic chromophores as potential NLO materials

Some new heterocyclic chromophores have been synthesized by greenway method. These chromophores have been evaluated by analysing their solvatochromic properties and molecular optical nonlinearities. Their hyperpolarizability (β) has been calculated theoretically. The non-zero tensor components of the imidazole derivatives reveal that they possess potent non-linear optical (NLO) behaviour. Measurements of absorption solvatochromism have been interpreted with Marcus and Reichardt–Dimroth solvent functions to estimate the transition dipoles. Good correlation exists between absorption as well as fluorescence wavenumbers obtained by the multi-component linear regression employing the Taft and Catalan solvent parameters with the experimental values.

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► The non-zero tensor components reveal the non-linear optical (NLO) behaviour.
► Solvatochromism interpreted with Marcus and Reichardt–Dimroth solvent functions.
► Multi-component linear regression employing the Taft and Catalan solvent parameters.
► The observed positive ρ2D values reveal the β-tensor components cannot be zero.
► Push–pull effect and occupation quotients of π* and π orbitals in imidazoles.