Pyrazole based solid state emissive NLOphores with TICT characteristics: Synthesis, DFT and TDDFT studies

•Novel pyrazole based push–pull dyes were synthesized and characterized.•Dyes exhibited blue to red solid state emission properties.•Dyes are showing twisted intramolecular charge transfer properties.•Nonlinear optical property study based on solvatochromism and DFT.•DFT and TDDFT computation were performed for photophysical property study.

A series of pyrazole based D-π-A derivatives with large stokes shift have been synthesized from 1,3-dipheny-1H-pyrazole-3-carbaldehyde by reacting with a series of active methylenes and characterized by spectroscopic analysis. The synthesized dyes show blue to red solid state emissions in the range of 441–604 nm. All the pyrazole dyes, except dye 2.3.6.4-((1,3-dipheny-1H-pyrazole-4-yl)methylene)-3-methyl-1-phenyl-1H-pyrazol-5(4H)-one, display solid state emission characteristics. Experimental absorption and emission wavelengths measured for all the synthesized dyes are in good agreement with those predicted using the Time-Dependent Density Functional Theory. In this paper, the static first, second hyperpolarizability and its related properties estimated for pyrazole based “push–pull” dyes using B3LYP functional with 6-311G(d) basis sets. We have performed experimental calculation to determine the first hyperpolarizability using solvatochromic shift method. These dyes show high first hyperpolarizability in the range of 39.96–296.35 × 10−30 esu by theoretical method and 35.8–302 × 10−30 esu by solvatochromic shift method.

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