Synthesis and spectroscopic characterization of nicotinaldehyde based derivatives: SC-XRD, linear and non-linear optical studies.

• Synthesis of derivatives is done through Suzuki-Miyaura coupling reaction. • Structures were analyzed through different spectroscopic techniques. • The experimental results show good agreement with theoretical results. • NLO and electronic properties were also studied. In this study, new arylated derivatives of pyridine named as 6-(4-tertbutylphenyl)-nicotinaldehyde (TBPNA) and 6-(4-hydroxyphenyl)-nicotinaldehyde (HPNA) were synthesized by Suzuki Miyaura C C coupling approach. The structures of newly synthesized compounds were authenticated by spectroscopic techniques like FT-IR, UV-Vis, and 1H-NMR. Furthermore, the structural features of TBPNA and HPNA were explored by using the single-crystal X-ray diffraction technique (SC-XRD) showing monoclinic crystal structure and P2 1 /c space group for both compounds. For a comprehensive study of the compounds, a computational quantum chemical study is also performed by using the density functional theory (DFT). The said compounds were optimized using the B3LYP method and a 6-311++G(d, p) basis set. The comparison of theoretical (DFT) and experimental (SC-XRD) data on structural parameters displayed good agreement. Frontier molecular orbital (FMO), natural bond orbital (NBO), the molecular electrostatic potential (MEP), and time-dependent density functional theory (TD-DFT) were also performed at the B3LYP/6-311++G(d,p) level of theory to get complete insights into electronic communications, intramolecular charge transfer (ICT) process, electronic transition and oscillation strength. The optoelectronic and non-linear optical (NLO) responses of the synthesized compounds were determined by computing the total dipole moment (μ tot), average polarizability ⟨ α ⟩, and the first hyperpolarizability (β tot) at different functional(s) such as HF, M06, M062X, CAM-B3LYP, LC-BLYP, and B3LYP, paired with the 6-311++G(d,p) basis set. The B3LYP method exhibited the highest values of ⟨ α ⟩ and (β tot) for HPNA and TBPNA , which were found to be many times higher than the value of urea (⟨α⟩ = 34.055 a.u., β tot =90.527 a.u.), used as a standard NLO material. [Display omitted] [ABSTRACT FROM AUTHOR]